It would be useful if VRayDecal supported the standard 3ds Max Material modifier without losing its decal functionality.
I need to render a logo in different colors in different frames. Usually I would use a multi-sub material for that and then animate the Material ID to achieve that result. This works for everything else except for V-Ray decals so it would be nice to make that work.
Starting at the 10:20 mark in this video, you can see a workflow that roughly fulfills your requirements.Use UV mapping to simulate decal features https://www.bilibili.com/video/BV1eyR5YrErJ/?spm_id_from=333.1387.upload.video_card.click&vd_source=70803050ec08b5933f6fe4fc9b69623a
You can easily do this with a VRaySwitchMtl instead. Attaching gif plus the sample scene:
logo_switch_mtl_sample.7z (78.5 KB)
Thanks @hermit.crab . You just blew my mind a little bit. Completely forgot about VRaySwitchMtl.
Here’s one issue though. Is there a way to add more than 9 material switches? For this particular use case I would need 30 
Sadly, no. But you can “chain” as many VRaySwitchMtls as you want.
A better way may be to use VRayMultiSubTex and its ID Generator slot. In the following gif, I use a Frame Number OSL, convert it to a float value, and plug it into the ID Gen slot (any float will do):
VRayMultiSubTex can hold up to 99 texture slots, which should be plenty.
logo_color_switch.7z (73.8 KB)