how to generate mattes from objects which use multisubtex

[super gnu]

ive been asked to provide mattes of every material in my scene. however a lot of the materials (being various coloured plastics) i have done with a single material and a multisubtex to generate different colours, sometimes in Node ID mode foor nice random variation and other times in "face id " mode for specific assignments.


obviously if i use mutimatte set to material ID, i get a single matte for all the plastics, which is useless. any work-arounds which dont require reassigning all my materials?

[Morbid Angel]

have you tried cryptomatte? its pretty great if they use a comp software which can utilize this plugin. Otherwise you would have to plugin multisubtex into vray extra tex element with selection exclude list (painful process)

[jonahhawk]

Multimatte will work with MAP IDs as well as Material IDs. This works in any mode of the VRayMultiSubMap.
If you have fewer than 16 colors, you can set each color using a map, such as VRayColor and then set its ID to 1 through 16.

[super gnu]

ahh!.. so, you are using a vraycolor as a map in the multisubtex.. and assigning an id to that vraycolor? i never thought of that, ive just been using colours straight in the multisubtex. in fact it never occured to me (in 20+years of using max) that you could assign material ID's at the map level. ive only even used them for materials.

thank you for that little gem! i love the fact that even after all this time i still learn new things about max.

[super gnu]

hmm, doesnt seem to work for me. ive replaced all colours with vraycolormaps, and set the ID's from 1 -16 on the maps. i created the multimattes, and ticked "is matid".

my render gives black multimattes.

[super gnu]

ok, it was user error. i had previously run an auto multimatte script, and it assigned an id override to those materials. i took that off and it works as advertised.