I must be doing something wrong, because I cant imagine this is how it works…So, I have a road, with a car, and a decal doing a white line on the road. So far so good. I need the road and the car rendered seperttely. I create render layers for the car, and road. Shadow of the car is there, the decal white line is there, car is hidden, the road render is fine.
I render the car layer, which should have the road and decal turned off to primary visibility, but still render into the car as reflections. Also, the alpha channel should only be the car…however it isnt…I cant seem to get the decal out of the car render. I have tried every tix box, vray object properties, everything. Nothing seems to let me hide the road and decal, and get a clean car render.
Ive attached two images, one of the render, one of the viewport.
Add the road to a new collection (in your render layer) then add a material override to the roadlayer with a default shader. or turn off the decal with an absolute override in its settings, for that render layer.
I need both the road and the decal to have their shaders on them as they need to reflect into the car. It all works fine with the car and road visible. I seem to have found part of the culprit…the road is in a vray obj prop, and set to “matte object” and -1 alpha. If this is turned off, and I set the road to primary vis “off”, then the decal behaves.
So, do decals not work on objects that are set to “matte object”?
My fix to just get this shot rendering, is the make a select set group for the whole car, set the render mask mode to “set” and load the car select set in. This clips off the glitching decal, and keeps my road and road markings reflecting into the car correctly.
My fix isnt ideal for this, as the anti-aliasing on my car when using “object set” mode mask in render settings is awful…Im not sure why, but its so jagged. Ive gotte by so far by eroding the mask a pixel in photoshop, but I really wasnt expecting another issue with this decal setup.
Itd be nice to hear if decals do work on matte objects…I would expect a decal to either just be turned off to primary vis in this situation, or just be hidden from view by the matte surface its applied to.
In 3ds Max (there was even a thread about this), decals were decided not to be visible on matte objects (the behaviour you expect). However, indeed, in Maya the behaviour is the opposite. I’ll write an improvement request on your behalf.
Really appreciate that. Pretty essential in an automotive workflow with road markings etc. Really love full control over the placement, and motion blur of the markings, but need them gone when they need to be gone for primary vis, but still reflect into the sides of the car.
