HDRI Vray Rendering 3d Max Tutorial

30 Aug, 2012 renderstuff (Staff Author)

Hello everyone!

In this tutorial we explain what is the HDR rendering and how you can control the brightness of the final render using it, easily getting rich and outstanding pictures.

This tutorial answers the following questions:

- What is HDR?

- What does LDRI mean?

- How to post-process HDRIs using Photoshop?

- How to render HDRIs from V-Ray?

- Which image format is the best to save HDR renders?

- How to deal with ovebrights in the window and near it?

- How to lighten the dark rendering?

Introduction

This tutorial tells how and why we need to render images with high dynamic range. Before we start, it is important to note that current tutorial doesn't limit you in using the 3d software. It is equally useful for 3ds Max & V-Ray users as well as for anyone, who wants to meet the practical side of using HDRI techniques for rendering photorealistic images, but uses any other soft.

For justice' sake, we'd like to mention our tutorial series about the V-Ray renderer settings. There we have repeatedly referred to HDRI rendering. Now it is the time to explore the HDRI rendering in detail.

What is HDR

For some time past, the term HDR in computer graphics became quite popular. So, there is a little confusion about meaning of this abbreviation and its spelling. Actually, it is very simple to understand the principle. In all such terms, only the first three letters HDR are important. They mean High Dynamic Range. The all other letters that come after, do not really matter. For example, HDR may stand as an independent term that means the high dynamic range in all senses. But it can be supplemented with word 'images' what looks like 'HDR Images' or HDRIs. This phrase means the images with high dynamic range. Also, you may see a lot of publications, including this one, the word HDRI, the last letter of which means 'imaging'. All these terms are synonyms and are used depending on context.

So, the High Dynamic Range Image is the image with the high dynamic range of colors, where the brightness of one pixel may differ from other a lot. In other words, the brightness level of the most lit area of the image may very significantly differ from the darkest area of the same image.

As you can see, the explanation itself doesn't cover the literal sense, and the purpose of the HDR technology is hardly imaginable yet. But it is so just until you come across the problems of the images with low dynamic range called LDRIs. Let's look on the typical example of the LDR image problem from photography. Part of our readers has already met with such problems and the next chapter will seem very familiar to them. For all the other readers, next and further chapters will help to realize the importance of using the HDR for creating the attractive images.

LDRIs Problem in Photography

Often, photographing outdoors, the shooting of the evenly lit composition just impossible, as we are unable to force the natural illumination to work in the suitable for us direction. In the result, we get the photo very bright in one place or too dark in other.

Take a look at the following photo.

This photograph shows the pirate's skull on a light-blue background of sky above the bay.

“Which bay?” you may ask. Well, the one on the shore of which the skull lays; the one which is overbrighted, or as the photographers say, overexposed by the bright sun.

The fact is that the photo camera, as well as any other light perceiving device, works in a limited brightness range. This means that the light information, the brightness of which is lower that this range is stored as black color; and the information with the higher brightness is recorded as white color.

This is exactly what has happened to our photo. The working range of the camera was shifted to the dark perception to make the main object, the skull, bright. But because of this shift the background turned out overexposed, as the camera with the current range has perceived and stored the well-lit areas far away as white color.

Now we have an overexposed photograph. What can we do to see the desired background instead of white overbrighted spot?

It would seem there is nothing easier than that: just correct the photo by darkening the background area.

Let's try this. We open the photo in Photoshop and lower the brightness to see what's behind the skull, by using the Exposure function, for example.

Unfortunately, instead of promised bay and sky, all we see is a dull gray color on the place of former white. Even the partially seen leaves at the sides haven't become clear. But why don't we see all the details in the bright area, even after making it darker?

This happens because the photo has not those details. There is a literally white color, the white pixels that were stored in the overbrighted areas, which was beyond the camera's range of perception. No manipulation or processing over this picture can reveal any of the details, hidden by the excess light.

LDR Images Compensation

However, as provident photographers, we have made one more shot from the same angle, but this time the perceiving range of camera was adjusted to record the bright colors.

Take a look at it.

Finally, we can see the bay, the sky; even the contours of the vegetation on the sides become evident. But the pirate's skull is too dark, or as it called in photography, underexposed. The photo camera with current brightness range stored the dark color values of the foreground objects as a black color.

If we try to alter the problematic area of the photo, same as we did in the previous case, but this time by a lightening, this wouldn't give us a good result all the same.

At the best, we discover the rough lines of the main object and, as a rule, the noise and artifacts always hiding in the dark zones. We must admit that here is nothing similar to what we expect from the good photograph.

Some of you already know how we can get the desired image, having both photos. Apparently, we can now combine these photos together: the first one would give is the well-lit skull, and the second one can provide us with a detailed background.

Made that, we get a satisfactory image that contains well seen dark and light areas, despite the initial technical limits of the photo camera.

HDR Benefits

Let's analyze what has happened when we've combined the two photos with low dynamic range to see all details in the single image.

For convenience, but without any specifics in numbers or real analogy, we can imagine the brightness range of the base composition, to which the camera can be adjusted, as a gradient scale. The showed photos are situated on this scale roughly; one in the dark area and the second in the light. The curly brackets coming out from the each photo show the limited range, covered by the camera at one moment.

By combining these two limited ranges of available brightness levels, we get one wide range. Now we can take the details of a relatively dark foreground and the details of relatively bright background from the mutual high dynamic range to get the single uniformly lit image.

So this is the essence and usefulness of the HDR. Having the info from the initially different brightness ranges, we can use it for getting single image with all details we want.

HDR Images in Computer Graphics

Returning to our photo example, you could suppose that LDR images can be combined by trite cutting and pasting the some details over the other. Well, we can do it this way, but such technique of the lighting ranges merging is irrational thus can be hardly called professional. Another thing is to merge few LDR images to a single HDR image. This is the method used in computer graphics nowadays.

To record and store the light data of a high dynamic range the usual picture formats aren't suitable. The problem here is that the regular LDR image formats can store only the limited range of brightness levels due to their technical peculiarity. For example, the well-known JPEG stores the brightness data in 8 bits so its dynamic range is just 1 to 256 (28=256). That means that usual 8-bit format can store only 256 levels of brightness. There also are 16-bit formats, which can store much more levels of brightness, but they are limited too and cannot provide the enough brightness reserve for further recovering of the needed details.

Quite another situation is with another type of formats, the 32-bit images. They can store the unlimited dynamic range of the brightness levels. 32 bits allow storing colors as a so-called floating point numbers; that means the infinite dynamic range. That is the reason to store the HDR images in a 32-bit graphic file formats.

Now we can continue to follow out photo example, since we know what HDRI is literally.

To take as much as possible light data from the shot scene, we have made a number of LDR photos with different exposure setting.

Having few LDR shots, made with camera that was adjusted to different exposures, only thing left to do is to merge their brightness data to a single HDR image. This is very simple task, as there is lot of software capable to marge to HDR automatically or semi-automatically. We have used Adobe Photoshop's included functionality Merge to HDR in 32 bit mode that can be found in File > Automate > Merge to HDR. Thereby, we got a HDR version of our photograph.

Now that we have the HDR image, we got to do an afterwork on it. Namely, we need to select the excessively dark areas and light them, and vice versa, select the overbrights to recover the hidden details. Such method of LDR images merging is preferential, as it allows doing accurate soft selections of problematic areas without any muddle with layers, files, and their mutual arranging. The HDR workflow makes a post-processing of images a very simple and clear task that can be perfectly done by almost anyone.

HDRI in 3D Rendering

At a first glance, the technique of obtaining the HDRIs from renderer may seem similar to those used in photography. So, it would seem that we need to render few regular visuals from the same camera with different exposure and then merge them to a single HDR image. Again, we can do it this way, but the advantage of working with modern rendering engine is that it isn't burdened by photo technology drawbacks. The renderer does its calculations in high dynamic range, i.e. it is HDR initially. And the main feature coming from this fact is that the render engine allows saving the results directly to HRDI format.

What does it give to us? This feature leaves us from the exhausting quest of collecting the number of images with different exposures, as it is with photos. Moreover, the dynamic range of stored brightness values by two, three, or ten LDR images is still limited. In the same time, the HDR render is limited only by factual brightness levels present in actual scene. It contains all the brightness levels, just like it is in a real world.

As you may guess, the HDR methods used to recover the hidden details of the photograph in 2d editor, described in previous chapters, are suitable for renders as well. Which 3d artist, who had to render an interior scene, haven't faced the problem when the light source in a window creates large overbrights on a ceiling, window opening and curtains? Such problem cannot be solved without altering the lighting of the entire scene and making the illumination of other areas worse as this often done by “dull” settings of color mapping. Who hasn't met the situation when one area of the final rendering comes out too dark and its lightening is impossible without re-rendering the whole image after changing the scene lights power?

HDR rendering leaves these problems behind.

Yes, the rendering seen in frame buffer still has all the drawbacks as before. But all of them can be easily eliminated in a few minutes by editing the saved HDR render in Photoshop. The post-processed render would no longer have overexposed spots and excessively dark zones.

Photorealism and HDRI

We can often see the delusion claiming that a rendering is completely not like the real life situation. For example, some say that described above overbright and excessive dark problems are solely the renderer's fault. They say a renderer that creates such images is simply not physically correct and we should do a better work under the scene lighting. But, in fact, those who say so are wrong. Moreover, the limited dynamic range effect is present not only in computer imaging.

Even when we ourselves look with a naked eye on a very bright object in a dark surrounding, our eyes have to adapt to a brightness of this object to see it normally. But as we begin to look on a darker part of our surroundings, the eyes again adapt to a new level of illumination.

You can perform an experiment: go outdoors and look at the clear sky for a moment, then back to room and look around. You may seem that there is very dark indoors, despite the room was well lit a moment ago. This happens because the eye, adapted to a very bright sky, cannot normally perceive the illumination of a relatively dark room. In other words, the dynamic range of human eye perception is also limited. Later, the eye, of course, will adapt to a room illumination but this process will take some time.

Try and remember how the typical pirate from the tales and fantasy films looks like. This is one-legged man with a hook instead of a hand, who wears the most typical attribute of a seacock, the black eyepatch. Many think this patch covers the injury, in which the pirate lost his eye during the battle for boarding another vessel.

There is no doubt that there were one-eyed pirates but there is also an explainable assumption about pirate's eyepatch. It could be an instrument equally important as a spyglass or compass for two-eyed sailors as well.

The eyepatch is useful when one needs to see well in a dark hold after lowering from the bright ship's deck. Coming down, the sailor moves the black patch away to open the covered eye that is immediately ready for perceiving details in a dark environment.

This fact once again shows that not only the usual photography or regular rendering show the limited brightness range. The human eye, at the same time, perceives the world in LDR. By covering the one eye from the high brightness levels, we can use it for seeing dark things without a need to wait the adaptation. Using this trick, the sailor compounds different dynamic ranges of brightness for seeing details better. The same we are doing using HDR techniques in imaging.

So, when on your image the main scene looks greatly lit, for example the room interior, and the window is burned by sunlight, do not blame yourself for incorrect lighting setup. In most of cases this is normal situation and it is physically correct.

However, despite the theoretical correctness, this is not always look aptly or artistically how it is expected from the professional photograph or 3d rendering. Then the skills in HDR images handling become useful.

HDRI Rendering in V-Ray

V-Ray has the only function responsible for dynamic range of the render, it is Clamp output. This function can be found in a V-Ray:: Color mapping rollout on V-Ray tab of a Render Setup window. Clamp output cuts off the high brightness values that come beyond the RGB space and thus makes the calculation of some render effects better. But it is true only if we render in a usual dynamic range, the regular LDR image. In the case of HDR, the enabled clamping will do a disservice for us by cutting off the real full brightness values. That is why we need turn off the Clamp output checkbox for rendering HDRI with full 32 bit colors.

This is the all V-Ray setup for performing HDR rendering. But, before rendering HDRIs we need to make clear one important thing.

The feature of all HDR formats is that the data they store is scene-based. Thus, the brightness values of each pixel in HDR format is saved linearly, just as it was originally. If we draw an analogy with the photography, then as the sensor of digital camera has perceived some brightness level, so it will be stored to a 32-bit file. You may seem it is an obvious thing without the extra explanation. But the problem is hidden in the fact that when we organize the correct and comfort workflow in 3ds Max and V-Ray, we always apply the gamma-correction to our images on a rendering stage. More on this subject please read in an article why we need Gamma 2.2 in 3ds Max. Despite that we save to a 32-bit format the gamma-corrected image, Photoshop for example, considers it linear. Consequently, our image will be a subject to a gamma-correction once more. In a result, instead of expected normal image as it was in V-Ray frame buffer, we will see very bright picture.

Those who have thoroughly read our previous tutorials, namely the tutorial about antialiasing and color mapping settings in vray, may notice that Vray has Don't affect colors (adaptation only) function, which is designed for simple switching to a linear (gamma 1.0) workflow. Well why wouldn't we use it in such appropriate moment? Unfortunately, this function is too straightforward. It turns off the influence of the Gamma parameter as well as the Color mapping type on our rendering. This fact entirely eliminates the possibility of trouble-free switching to theoretically correct 1.0 gamma setting in HDR rendering. In an overwhelming number of cases, the obtaining of satisfactory photorealistic images using the standard Linear multiply color mapping method is unreasonably hard.

On practice, the obviousness of working with the usual color mapping settings is determinant. That is why, after we open the gamma-corrected render saved to a 32-bit format we need to perform the reverse gamma-correction in Photoshop. How it is done is explained in following chapters.

But first off let's look into the settings of the 32-bit file format available in 3ds Max for saving renders.

Saving HDR Render in 3ds Max

After the rendering is complete, we need to save it to HDRI file format. For example, HDR render can be saved in a modern developing format called OpenEXR. When saving to this format, 3ds max shows the window with a lot of options, the number and exact name of which vary in different 3ds Max versions. Despite the differences, the main options are available in all versions and they must be set as follows.

Format is an option that sets how precisely the color data is stored. Choose Float or Full Float 32 bit per channel to save the highest accuracy of HDR colors. Other values may reduce the size of the saved file at the cost of slight color errors.

Compression defines the type of file compression. The compression reduces the file size by standard compression methods. In this option we got to select method ZIP of any type. The part of other compression methods doesn't compress the file too much, and the other part (lossy) compresses the file with significant quality loss. Neither the one nor the other fits our needs.

Type (or just the channels list) is a list of color channels that will be stored in a file. We need to choose R, G, B, and Alpha or RGBA as a single option. Turning off the any of the mentioned channels or selection the Mono option will limit the color information of our file, so their choosing is not reasonable in a majority of imaginable situations.

All other options should stay as they are originally; their default values are correct and need altering only in a special cases, describing of which is not a subject of current publication.

Now, since the click on the OK button, we have the HDR render in a true 32-bit format.

Using the HDR Rendering

Let's back to the purpose, for which we made the HDR file. We have made it for the following editing and recovering needed details that couldn't be rendered in a limited dynamic range of the LDR image. For obvious demonstration of such situation in 3d, we have created a simple scene and rendered it. The scene itself is an attic with a bed in front of the window.

As you can see, as a result of the geometrical features of this room and small size of the window, that is the only light source in this composition, the whole interior is badly lit and, at the same time, there is a great white spot on all adjoining window surfaces. It is especially noticeable on the window frame and recess in the left wall. This is a typical problem of LDR renderings. To solve it, the HDR image must be edited as was described above. This time we'll look into this in detail. You can follow all the described actions using the original files, attached among the main steps further.

To start postwork with our render, we must save the render to an EXR format and open it in Photoshop.

Please notice that if your rendering was made with gamma 2.2, the reverse gamma-correction must be done before doing any processing. This can be easily done by applying the adjustment layer  Layer ▹ New Adjustment Layer ▹ Exposure ▹ OK and moving the slider called Gamma Correction to the right until it reaches value 0.45.

This action restores the look of our HDR image to the one we saw at the renderer's output. This will be our starting point for post-processing. If you have used the linear workflow with gamma 1.0 and your rendering looks ok right after opening, you don't need to perform the described reverse correction, just skip this paragraph.

Here is the sample of initial image, containing the HDR rendering and a reverse gamma-correction layer (as our render was made with gamma 2.2). Feel free to download and study it.



hdr-raw-gamma-compensated-render.tif

One thing to mention about files is that *.exr format cannot save the data about adjustment layers and masks. But this is not a problem, because the edited EXR can be saved to native Photoshop formats *.tif or *.psd, which fully support the work with layers and the 32-bit color depth as well since Adobe Photoshop CS2 version . That is why the above and following files are saved in TIFF 32 bit format.

The description of the all possible options in post-processing of photographs comes beyond the subject of this tutorial and is more 2d than 3d. However, to make you easily follow directions, we have explained the one most usable and obvious way of altering the problematic zones of the 3d rendering in Photoshop.

First thing we need to do is to examine the bad areas of our HDR image. Let's start with excessively bright areas. On presented here example the most significant overbright is at the actual window opening, so we need to dim that area. At the very bottom of the  Layers panel find the black/white circle icon called Create new fill or adjustment layer, click it and choose Exposure item in the appeared list. The adjustment layer is created. Right after we do this, the parameters such as Exposure, Offset, and Gamma Correction become available in the  ADJUSTMENTS tab of the appeared panel. By moving the slider Exposure to the left, we darken the entire image and also recover the missed details in bright spots. Adjust the Exposure until all desired details show up in the brightest area of the rendering. Once have done that, we need to limit the effect of this layer and remove the darkening from the other normally lit (or dark) render areas. Having the last Exposure layer selected, fill its mask with a black color using  Edit ▹ Fill ▹ Use: Black function. The darken effect completely disappears. Now, having fully black mask, we can begin to literally paint the darkening, restoring the effect in a problematic zones. Take a soft brush of a white color, set its Opacity at the panel above to nearly 5%, and paint over the bright places, periodically releasing the mouse button. The more times you draw over the white spots by a brush, the more they darken. Probably, during this process you may seem that overall darkening effect is need to be more or less significant. Feel free to alter the Exposure value on the ADJUSTMENTS tab, as it is available at any moment. After finishing the painting darkening, we have our rendering free from too bright areas.

You can look at the adjustment layer made for obtaining the above result by opening the following source file.



hdr-render-darkened.tif

Like this, in just a few minutes we have completely removed the ugly overbright on the rendering without any manipulations with initial scene lighting setup or renderer's color mapping settings.

Take a look at the picture again; there are quite dark areas behind the wooden ceiling beam and under the bed. They just beg us to light them up. Let's continue the work under the HDR 3d rendering.

This is done similarly. Add one more Exposure adjustment layer and alter the brightness of dark areas. To light the dark places on HDR rendering, the most convenient parameter is Gamma Correction. Fill the layer mask with black color, softly develop problematic areas.

The file below contains source adjustment layers, including the last one that lights the unpresentable dark zones.



hdr-render-complete.tif

That's all. Only thing left to do is to convert our 32-bit image to a usual LDR format. This is made by command  Image ▹ Mode ▹ 8 Bits/Channel. In an appeared warning about color depth change, use the button Merge. Then, in the HDR Toning panel choose Method: Exposure and Gamma and click OK.

Conclusion

You can see how we can simply deal with any overbright and the shadow density in a needed area of the image without re-rendering. In most cases, even the accurate tuning of the exposure on the 3d step is not needed. This frees us from messing with the Multiplier in Color mapping or film speed of VRayPhysicalCamera. All this can be done after rendering, in 2d editor. Moreover, often, the dynamic range of HDRIs is enough to slightly alter the brightness of the light sources and the objects they light.

HDR rendering is the full control over the brightness of your 3d generated images.

We hope that after reading this tutorial you are able to use HDRI for enhancement the visual quality of your photorealistic 3d renderings with ease.



1 Sep, 2012 Valera
1 Sep, 2012 # Re: HDRI Vray Rendering 3d Max Tutorial
Thanks bratish 👌


1 Sep, 2012 Naugal
1 Sep, 2012 # Re: HDRI Vray Rendering 3d Max Tutorial
Tell me please, what is the reason: when you open your file, and any 32-bit image, neaktivenny some teams to work with layers, in particular Tott also "Create new fill or adjustment layer"? I use Photoshop CS 6. Do all the instructions 1. Render scene 2. Saving OpenEXR ImageFile (taking into account all that you specify when saving settings). 3. To open the file in Photoshop and ... all!) Then I activity "Create new fill or adjustment layer" and, respectively, the lesson can not move on! This option becomes available only if I translate the image in 16-bit. I open the file you downloaded. Adzhasment layers are visible, but are not active and do not work. Just Extended and not work ... it seems these features now try to establish some or other version ... Accomplish your goal)


2 Sep, 2012 Anton (Staff Author)
2 Sep, 2012 # Re: HDRI Vray Rendering 3d Max Tutorial
You open the downloaded have fever? They all have tifah adzhastment handholds. They have you seen? They do you work? If yes, then you something is not understood in Photoshop. If not, you probably have bugs version of Photoshop. With CS3 Extended and further, adjustment layer works in all assemblies with fully 32 bit formats 👌


2 Sep, 2012 Killot
2 Sep, 2012 # Re: HDRI Vray Rendering 3d Max Tutorial
Tell me why when you open your file on my computer mask adjustment layer is not black and gray?


2 Sep, 2012 Maks (Staff Author)
2 Sep, 2012 # Re: HDRI Vray Rendering 3d Max Tutorial
Killot, please specify which file and how it is not black? In fact, none of the files should be absolutely black mask. If you mean overall greyness shading mask layer, which means that the shading is applied not only to any specific location (white), but also the whole image in some degree (gray). This is the flexibility of this approach - gradation mask in any areas of the image indicate the degree of application of adjustment layer.


2 Sep, 2012 Killot
2 Sep, 2012 # Re: HDRI Vray Rendering 3d Max Tutorial
Thank you! I then thought of myself =) And you might not have to share the stage? I would like to conduct an experiment, based on the model of your lighting.


2 Sep, 2012 Anton (Staff Author)
2 Sep, 2012 # Re: HDRI Vray Rendering 3d Max Tutorial
Hello! The described technique HDR rendering is absolute and is applicable in any similar situation, not only for 3ds Max and V-Ray, and even more so, it is not tied to a particular lighting scheme. There is no need at all to you in this scene. As regards, wash away the scene, it's just a 3d model of the room with a hole for the window and VrayLight it. All settings are described in our lessons. Nothing else. So do take-Box, Cut a hole in it, put it VrayLight and experiment😉


2 Sep, 2012 Killot
2 Sep, 2012 # Re: HDRI Vray Rendering 3d Max Tutorial
So do =) Correct me if I'm wrong. It seems to me the use of HDR saves a great amount of time. It eliminates the long light settings, in low light conditions. I often put additional vray lajty the room because light entering the room from vraysky through portals in the windows is not enough, and the increase in brightness vraysky results in time for the nuclear glow. In addition, from the large of number of light sources, shadows disappear, right?


2 Sep, 2012 Anton (Staff Author)
2 Sep, 2012 # Re: HDRI Vray Rendering 3d Max Tutorial

If you use a workspace Gamma 2.2 , then in principle such a crown should not be, of course, if the room is designed right, and not as monsardnaya kennel, both in this example. If the same situation as in the lesson, then yes, of course, is that the gamma does not help.

But basically I'm doing, in most situations. Nominally tune scene, most right to require a minimum of post-correction, and more with her not mess around. Render, and then customize in the shop as I need. Of course, I already have some experience in this, and immediately see that you can leave on a post-correction, as well as light and tweak everything as necessary. But just do not mess around with adjustment of brightness / exposure scene in 3d😁



2 Sep, 2012 Sasha
2 Sep, 2012 # Re: HDRI Vray Rendering 3d Max Tutorial
I have the same problem that Naugal. I can not unlock the layer and all. Is this a bug Photoshop? I cs5


2 Sep, 2012 Maks (Staff Author)
2 Sep, 2012 # Re: HDRI Vray Rendering 3d Max Tutorial
Sasha, most likely so. Regulatory layers with 32-bit color at Adobe claims, should work since version CS2. In practice, they only work with the version CS3 Extended. Yet, whatever it was, CS5 is a newer version 🙄


1 Sep, 2012 Naugal
4 Sep, 2012 # Re: HDRI Vray Rendering 3d Max Tutorial
Hello) Indeed it was the version of the program, set himself Photoshop CS6 (version 13 x 64) Extended - all earned). The trick is that those that the installer can be found online under the guise Extended those are essentially no (or just cut the external plug-ins - I do not know). To open these files in a lesson with the active layers need plugin OpenEXR (check its availability in your Photoshop can be achieved by: Help -> About Plug-In - it should be displayed in the drop-down list). If not, then either look for another assembly, or to buy it separately (available for a trial 15 - day trial version)


5 Sep, 2012 SERDGIUS
5 Sep, 2012 # Re: HDRI Vray Rendering 3d Max Tutorial
Thank you guys, once again, tried and lo and behold I was something will turn up this post with a treatment like a blind man on a whim to do something without any understanding at all of the depth, etc. A brief but very informative article, standing a dozen of those that I had previously read and tried, we look forward to the next article.


6 Sep, 2012 Yellesar
6 Sep, 2012 # Re: HDRI Vray Rendering 3d Max Tutorial
Thank you for the lesson 👍 And what are the alternative formats except exr? For reluctant to reinstall Photoshop, there are all sorts of plug-ins etc. 🙄


2 Sep, 2012 Anton (Staff Author)
7 Sep, 2012 # Re: HDRI Vray Rendering 3d Max Tutorial

Ellesar, hello!

I myself had used the format * .hdr - Radiance Image File (HDRI) (* .hdr, * pic). It is, in fact, nothing is different from the OpenEXR Image File (* .exr), with the only exception that preserves transparency .exr * and * .hdr - no.
Although * .hdr have a nice bonus in the other. It can be viewed imeydzh viewer, for example, using the free XnView .

As for the rest, there is no difference.

As for the OpenEXR plug-in to Photoshop, it nominally should be built into any full-fledged version of the shop goes online. Of Photoshop, as well as 3ds Max is a package of plugins package. Almost all of their functions, it is some kind of plug-in, plug-in from the outside or built. So that alone, there is something to do with the OpenEXR is not necessary: ​​D



6 Sep, 2012 Yellesar
7 Sep, 2012 # Re: HDRI Vray Rendering 3d Max Tutorial
uh) is the same situation with .hdr format: | campaign is necessary to put a newer version to have two) there are pleasant things 🙂


2 Sep, 2012 Anton (Staff Author)
7 Sep, 2012 # Re: HDRI Vray Rendering 3d Max Tutorial
In that case the POI that formats plugins nothing to do with. Case 32 bits. Well I to it and am😁 Create a new file / document 32 bit in Photoshop adjustment layer and all Ranvier will not work. It does not work is not in a format in 32 bit space. This is a bug. We need to put another shop and that's it😉


6 Sep, 2012 Yellesar
7 Sep, 2012 # Re: HDRI Vray Rendering 3d Max Tutorial
pancake) clear) I'm not the sin means 🙂 thanks 👌


9 Sep, 2012 kuk
9 Sep, 2012 # Re: HDRI Vray Rendering 3d Max Tutorial
Took your proposed Tiff, Photoshop corrected hue and saturation, and then transferred to the 16-bit image, I corrected shadow and light. Action less distance is shorter.


2 Sep, 2012 Maks (Staff Author)
9 Sep, 2012 # Re: HDRI Vray Rendering 3d Max Tutorial
Cook, hello! Not all readers understand the way you proposed tone mapping. If you have knowledge about convenient methods, please describe them in more detail. Despite the fact that the lesson only formally captures the specific method to bring an HDR image in Photoshop, it will be useful to all alternatives 👍


9 Sep, 2012 kuk
9 Sep, 2012 # Re: HDRI Vray Rendering 3d Max Tutorial
Max, hello! I'll try for action: remove the layer mask - a mask used in Photoshop used only when it is without them, "by no means", or information peresvetlenyh and shaded areas simply do not have. In addition, the view from the window is no longer climbs its contrast to the fore. Correction - hue / saturation. regulates only the saturation and brightness, hue, not bothering. Brightness omit to display the details "in Peresvet" on the wall and the frame. Then saturated. Further, it seemed to me that the continued use of 32 bit - is unwarranted use of resources in this problem, and in addition, 32-bit is not allowed to use the correction of shadows and light. correction - the shadow / light. I put a tick more options. choose the shade values: the effect - at which the lighting and the depth is lost, then the width of tonal range and radius - it depends on the nature of the image; then the world - if you want, because in this case of a flare on the floor is easy to arrange a smudge; and the last correction - saturates tsvetokorretsiya reflex floor walls, and contrast - midtones, gets rid of the "haze" in the image. If you are satisfied with the quality can still edit anything ...


14 Sep, 2012 Aleksandr
14 Sep, 2012 # Re: HDRI Vray Rendering 3d Max Tutorial
Guys, welcome! Well, what did you do this lesson. You I once greatly helped with my renderer in HDRi, he even have an illustration of the opening is in the "photorealistic rendering processing" (which I am very proud of). --------------- I've been to this lesson to disassemble rendering in linear adjusted to 2.2 range, and use the checkboxes Don`t affect colors. Wherever I have not read the information (mainly foreign resources) about this option stating that using amendments to 2.2, it allows hands to remove the noise in dark areas, since the engine considers the stage of 2.2, but the colors leaves linear. ----------------- I remember that in your lessons, you do not recommend enabling this setting, and use Reinhard. But Reinhard still kills the information in pixels, as an adaptive type, and Linear only leave all the information necessary for HDRi. Maybe I read a bad lesson, but I did not understand whether you are recommend to use a ruler + 2,2 + Don`t affect colors or not? ---------------- If you are interested - here are my experiments with different types. I have checked whether the noise is so well cleaned in the shadows This is a source code This increase in scale


2 Sep, 2012 Anton (Staff Author)
14 Sep, 2012 # Re: HDRI Vray Rendering 3d Max Tutorial

Hello!

Yes, I remember the theme of post-process render 😁

I'll tell you so. In this lesson, and in others, too, described no theoretically correct approach, which, incidentally, we mention it, and describes only the most comfortable in the method. We are against sport rendering work needs to be comfortable, first of all, and not routinely correct and, of course, the work must be the result. Speaking about the results, I mean that in the V-Ray has an excellent way of direct influence on rendering quality and, in particular, on the amount of noise. Of course, we are talking about the DMC a Sampler .

In this connection, I recommend you use it in a splint method described as the most comfortable, and the noise, adjust the sampler settings, for example, lowering the Noise threshold, etc. 😉



14 Sep, 2012 Aleksandr
14 Sep, 2012 # Re: HDRI Vray Rendering 3d Max Tutorial
Noise Threshold I certainly use. But it is not the overall level of noise, and the noise in dark areas, where due to its adaptability Vray considers worse. And since we render in 32-bit mode, the shadow information is also important to us. I did not insist much on this process, rendering, and the way he takes on average longer than rendering with Reinhard and exhibitors. I just do not really understand why choosing 32x cue for post-processing, you use adaptive, not linear type. Yes, there are vigorous linear glare, but they are also cleaned post-processing without much straining. --------------------- As soon explain, I do not come in a hard dispute, 70% of their basic knowledge on the behavior of the engine, I exactly podcherpnul you. A bit confused, that I want to understand.


2 Sep, 2012 Maks (Staff Author)
14 Sep, 2012 # Re: HDRI Vray Rendering 3d Max Tutorial
Alexander, please carefully read the chapter on rendering in the vray . It is a question of preference for a comfortable and intuitive workflow and, except for the first obrazatsa She just dedicated to the question you asked. As for adaptability, there is no need to control the quality of the renderer through perversion with a value range; shadow quality is very simple governed by the general settings DMC sampler, as well as Anton said. Moreover, as you yourself noted, are calculated linear color longer, which is the last argument against the theoretically correct rendering in Linear.


14 Sep, 2012 Aleksandr
15 Sep, 2012 # Re: HDRI Vray Rendering 3d Max Tutorial
Max, I was confused😁😁😁 I quote your lesson on setting Color Mapping -------------------- Just for this purpose is the function Do not affect colors (adaptation only). Its essence is that it allows you to get the colors in a linear gamma 1.0, but the quality of the renderer is adapted as if it were a gamma value as exposed in the parameter of Gamma, such 2.2.//Eto very useful feature for HDRI rendering but in the universal V-Ray settings function Do not affect colors (adaptation only) should be disconnected, as for ordinary LDR render it not necessary .// ---------------- ---- that is, the lesson is about LDR - it is not necessary there. But at the same time in HDR, it is very useful. -------------------- Is it possible to use a bunch of HDR Reinhard + Don`t affect colors + Gamma 2,2. Perhaps I have just for this bunch of dissonance, as once taught me LDR Reinhard + Gamma 1,6 for more juicy pictures -------------------- Do not get mad at me, I have now formed a mess😁


2 Sep, 2012 Maks (Staff Author)
15 Sep, 2012 # Re: HDRI Vray Rendering 3d Max Tutorial
Alexander, yet do not pay attention to an earlier lesson on the Color mapping, the information about the said function a little bit wrong, it needs to be edited. So far, the hands did not reach. Thank you for your attention😉


14 Sep, 2012 Aleksandr
15 Sep, 2012 # Re: HDRI Vray Rendering 3d Max Tutorial
Okay, so I have a roof yet finally did not go =🙂🙂 Well, to secure - Do I understand correctly that the rendering in HDRi Gamma value in the SM should be 2.2? Unlike LDR, where it can be varied (in the older your comments on the forum, I do not just read about it). And then inflated scale lead to linear in the post?


2 Sep, 2012 Anton (Staff Author)
15 Sep, 2012 # Re: HDRI Vray Rendering 3d Max Tutorial
No, not right. More precisely correct, but if you just want to render the image with a gamma of 2.2 in the CM. For example, I was in the range of color mepenge, given initial (before post-processing), the density of shadows. If you want the picture was more contrast with the dense shadows, I can easily lower the gamma to 2.0 or even 1.6. In our proposed method, there is nothing to nowhere should not reconfigure. The process of rendering, smooth, like all renderer settings, nothing is different from the LDR render. For the only difference is that the tick is removed Clamp output. Herein lies the main advantage of this practical method, in contrast, from the theoretical. All you do, as before, just at the exit, technically, you get the pixels not 8u bit and 32-bit brightness. That's all. You better not drive themselves into the jungle. Just do it for the lesson. We have broken a head, for you, you just use the remaining operating time finished😉


14 Sep, 2012 Aleksandr
15 Sep, 2012 # Re: HDRI Vray Rendering 3d Max Tutorial
Well, thank you 👌


17 Oct, 2012 Aleksandr
17 Oct, 2012 # Re: HDRI Vray Rendering 3d Max Tutorial
Something I did not get. 1 attempt to save the file in the format of HDR open it in Photoshop, but I can not remove the lock from the layer and hence edit 2 attempt to save the file in a format EXR image on the screen, just one white spot gamma correction, to do can not edit layer also on the layer lock which again the same can not be removed. Tell me what could be the problem: |


3 Nov, 2012 Julia
3 Nov, 2012 # Re: HDRI Vray Rendering 3d Max Tutorial
It is a good lesson, RenderStuff! But my question is: under discussion vray I often read your answers like that, "the first mistake visualizers - too dark background behind the window, and that this does not happen in life, that the background is visible through the window in the room is well lit". And further more you say that the background should be almost overexposed. So, it turns out if you save and edit HDRi this lesson, which will be visible and the background behind the window and the interior - we have not photo realistic picture? Something I'm confused, then what to do: Light Damaged still do background behind the window or not? I did like the render interior for all your listed algorithms. At first there was a small glare of the window, but when I put the background, everything was beautiful, no glow. But it is not that realistic? Please help me please 🙂


2 Sep, 2012 Anton (Staff Author)
4 Nov, 2012 # Re: HDRI Vray Rendering 3d Max Tutorial

Hello!

The problem is not what we say, but that you try to do our advice thoughtlessly, like postulates, instead of understanding exactly the essence of what was said. This is not the right approach. For example, in the current lesson, our position on your question is clearly stated unequivocally. If to you, for some reason, the essence is not obvious, then let me try to explain it in other words.

There is a photorealistic rendering, that is, a similarity with a photograph, but there is artistry, that is, how beautiful it is perceived by the viewer. If we talk about photorealism, then, for example, the "nuclear explosion" outside the window, looks photorealistic, just as it would look in the photo. Nevertheless, such a picture does not look artistic, because instead of translucent tulle, for example, in the photo there will be simply a white spot. Total, photorealistic, not synonymous with artistry. Far from all that is realistic, is beautiful and acceptable to perception. Many girls, making themselves a photo on avtarku "vkontakak", carefully retouching wrinkles and pimples on the face, although they are quite realistic, because that's what a girl looks like. Nevertheless, the viewer does not perceive these very pimples as beautiful, this leads to a deviation from realism towards artisticity. The same goes for the rendering, which, in fact, is a selling illustration.

If we talk about the situation when the interior is lit by a bright scorching sun, and the cloudy blue outside the window, then in this case, this rendering does not look not photorealistic, not artistic.

It is necessary to search for a balance between artistry and photorealism, one that will not cause doubts about the realism of the picture, and will not cause "confusion" in the viewer because of the apparent inconsistency of illumination inside the room and in the window, which are actually a source of light in the daytime interior.

This is the approach proposed in this lesson. Having the ability to gently control the illumination of individual zones of the scene, smoothly choosing the balance of light and shadow, you can achieve the most acceptable result.

As for the question, "But how to find this balance?", Then the answer to it is banal: subjectively, "by eye". 3d visualizer is an artist who "draws" the right images with the help of modern software tools😉



5 Nov, 2012 Julia
5 Nov, 2012 # Re: HDRI Vray Rendering 3d Max Tutorial
Thank you, Anton, now I understand everything! 👍 I have to re-read your response this lesson and realized that HDRi come to the aid is under such catastrophic lit up when all else fails, just when you need to configure the correct luminance balance. And when there is no lit and are satisfied, you can save and LDR? You are here for example, are not always in HDRi save renderings? And just when you need it? Or all the same HDRi has some other advantages in the post-processing to the LDR image?


2 Sep, 2012 Anton (Staff Author)
11 Nov, 2012 # Re: HDRI Vray Rendering 3d Max Tutorial
When there is not lit and are satisfied, when you do not plan to post-processing, of course, in such cases the HDR rendering is not appropriate. We do not always keep to the HDRI renderings. For example, when rendering the animation, I always keep it in the sequent LDR format. The same applies to the subject of visualization. However, when it comes to interior visualization, in which the bright light from the window always illuminates the dark box of the room, especially when rendering a very complex and takes considerable time, then lose the information stored (and rnederya) in LDR, so that later, if image exposure requires adjustment, re-calculate all - silly. It is much easier, nominally, all interior visas do in HDRI 🙄


5 Nov, 2012 Julia
15 Nov, 2012 # Re: HDRI Vray Rendering 3d Max Tutorial
I see. Thanks! 👍


16 Dec, 2012 Sergey
16 Dec, 2012 # Re: HDRI Vray Rendering 3d Max Tutorial
About pasibo! what I was looking for!


14 Jan, 2013 iDesigner
14 Jan, 2013 # Re: HDRI Vray Rendering 3d Max Tutorial
Hello! svasibo much for the lesson! and voosche for all your lessons! 👍 are all very detailed and clear, even for girls), but one question I have is still there. I work in the Cinema + Vray with gamma 2.2, as it should be! When you save in .exr or .hdr or any 32 bit format, the colors really are razbelennymi, as it should be, but when I open them in PhotoShop CS5 they become as bright as when rendering without reverse gamma correction is 0.4545 a new feature or CS5? If it's important, I'm working in Mac OS and the monitor was calibrated at 2.2 gamma but even with a calibrated monitor, there should be no difference in previews and PhotoShop


2 Sep, 2012 Anton (Staff Author)
21 Jan, 2013 # Re: HDRI Vray Rendering 3d Max Tutorial
Hello! PC systems work mainly with Adobe Gamma, at most of Windows, iOS systems, another principle. Apple uses different color profiles system. We often render the movies, playing the main unit which is the iPad, and constantly confronted with the disparity range. So do not pay attention, above all, in the case of post-processing, to achieve the desired result at the output of Photoshop😉


14 Jan, 2013 iDesigner
22 Jan, 2013 # Re: HDRI Vray Rendering 3d Max Tutorial
Thank you so much🙂


6 Feb, 2013 dmitriy
6 Feb, 2013 # Re: HDRI Vray Rendering 3d Max Tutorial
Kind people!! Why do I have all white in exr? But about maksovskom viewed in Explorer, the picture is normal. hdr maintains normal. The problem has been, it did not respond


4 Mar, 2013 bryan
4 Mar, 2013 # Re: HDRI Vray Rendering 3d Max Tutorial
just to share.. had a bit of a problem with this workflow as photoshop wont let me add adjustment layers.. but i later found out that i wasnt using ps cs6 extended 😁 when i used in the extended version, it even lets you adjust the exr directly.

anyways thanks guys! great job on the tutorial.

2 Sep, 2012 Maks (Staff Author)
4 Mar, 2013 # Re: HDRI Vray Rendering 3d Max Tutorial
Hi bryan,

You're right, not all Photoshops lets us to use these advanced functions, even the same version may work here but don't work there. The Adobe has very smooth description on this. So, as you have already seen, the most reliable way to ensure everything works great in terms of HDRIs is to use the latest and the most complete version of Adobe Photoshop.

1 Feb, 2014 Neeraj
1 Feb, 2014 # Re: HDRI Vray Rendering 3d Max Tutorial
These tutorials are very simple and beautifully explained I refer to these tutorials always and I find this place a great and handy whenever I need.Thank u very much.

8 May, 2014 A.Battikhi
8 May, 2014 # Re: HDRI Vray Rendering 3d Max Tutorial
what a really ! as it such a complicated technique , as u guys make it simple , useful and logical to understand ... this site is amazing 👍 👍 thank you for your effort

28 Jul, 2014 Colin
28 Jul, 2014 # Re: HDRI Vray Rendering 3d Max Tutorial
Hi Anton and Max

I would just like to thank you so much for your wonderful insight and sharing it for free. It's not often you come across a site about VRay that has tutorials for free and so easy to share! I have no doubt in my mind that karma is going to repay you in kind!

Regards
Colin Langley

21 Aug, 2014 Letchik
21 Aug, 2014 # Re: HDRI Vray Rendering 3d Max Tutorial
Great tutorials! Thanks 😉

1 Dec, 2014 Roy
1 Dec, 2014 # Re: HDRI Vray Rendering 3d Max Tutorial
what source of light did you use for this scene? is it VraySun or HDRI outside of scene? because i'm a bit confuse.

thank you i hope someone will response to this admin thanks. 🙄

2 Sep, 2012 Anton (Staff Author)
1 Dec, 2014 # Re: HDRI Vray Rendering 3d Max Tutorial
Hi Roy,

We use VRaySun as a direct light source and VRaySky HDRI as an environment map.

It's pretty standard method for interior and exterior lighting setup 😉

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