Hello!When geometry is attacked with different materials, 3ds Max displays a window with a literal question about what to do with the materials of these objects.Note that the assignments of new material IDs and geometry IDs are the results of Boolean operations and the main thing is the geometry and material of the current (that to which you are attacking) the object.Attach Options:- Match Material IDs to Material3ds Max creates and applies a new Multi / Sub-Object material to the geometry, with the number of material IDs equal to the total number of materials of both objects before the attack. In doing so, it also modifies the ID of the obtained geometry, so that visually the geometry of the merged objects has the same materials on the same polygons, only the ID of these polygons is matched to the ID of the generated mtiltsab.Condense Materials and IDsAffects the result of the Match Material IDs to Material operation, namely, it cuts duplicate materials, as well as the materials of which are in the multimaterials of the attacked objects, but they are not used directly in the invasive geometry. For example, if you attach an object with ID2 but have multi-material with ID2 and, say, ID6 to the current object with ID1 geometry and the only material, then the resulting Multi / Sub-Object material after joining will have only 2a ID. If Condense Materials and IDs is turned off, the resulting mate will have all 3 and IDs.- Match Material to Material IDs3ds Max creates and applies a new Multi / Sub-Object material to the geometry, with the number of material IDs equal to the total number of geometry IDs of both objects before the attack. Even if we attack two objects, each of which has one material (not a multisab), and the object polygons themselves have several IDs, the newly created Multi / Sub-Object material will have as many IDs as the polygon IDs in the current and attached object. Visually, both objects will look the same as before joining.But this is in theory, in practice, for example, for me, Match Material to Material Ids persistently does multisab with ID1 and ID4, even if such IDs are not in the current not in the attacked object. He adds them stupidly. In the end, if I attack one geometry with ID, say 2 and 3, and the second one, for example, with ID 8 and 10, then 3ds Max will create a multisab with ID 1,2,3,4,11 and 13, that is, with In order to make a mate with the 4th ID 2,3,11 and 13, he does the mate with the 6th ID 🙄- Do Not Modify Mat IDs or Material3ds Max creates and applies a new Multi / Sub-Object material to the geometry, with the number of material IDs equal to the total number of materials of both objects before the attack. In this case, it does not modify the ID of the obtained geometry at all, leaving them as is in the original objects. Of course, in this case, the new (received after the attack) object can visually look different, since a new material with a different numbering of the materials ID will be applied to the old IDs of its polygons.