Vray Material - Render geometry as solid color

[michaelwbell]

Hi All,

This is likely a very basic question, but I would really appreciate some advice!!

I'm Trying to create an effect where geometry in an animated scene is rendered as a flat colour - no shading, etc. But it must cast shadows.

Similar to the silhouette's in this animation, except they are 3d characters (not 2d cutouts).

So in a nutshell. If I apply a material to certain geometry, in the render it will appear as a solid flat color.
The Geometry will cast shadows. But will not receive any lighting, shading, shadows, etc.


So far, I am doing this using the VrayLightMtl - It is rendering a perfectly flat color of the 3D objects. All good.

Second approach will be to render out Vray Mattes for the Silhouettes and just making them a flat color in the compositing stage.
Would love to have the result in the Beauty pass though.

But i'm just wondering if there's a better way to do this (that will also render really quickly)?

[Mokiki]

You can use the override material. Use the light material in the base material slot and use another vray material in the shadow slot. So you get shadows but no shading on the object itself.

[michaelwbell]

Hey Oliver,

This was great, thanks for the screengrab as well. Fantastic.
I have used this method for the current project.

So, there is no other way to get a perfectly flat color for diffuse channel?
Apart from using VrayLightMtl or doing the effect in the compositing stage with mattes?

[Svetlozar Draganov]

Another approach would be to use Ink'n Paint Material with - it will not generate a perfectly flat color but the difference between shaded and unshaded area be unnoticeable.


or, using Self-Illumination property in VrayMtl with black diffuse color.

[Mokiki]

[...]

or, using Self-Illumination property in VrayMtl with black diffuse color.
[ATTACH=CONFIG]20098[/ATTACH]

Wait that works? XD That should have been the first thing I tried :/
All in all good to know!

[Svetlozar Draganov]

Yeap it works(it was the last thing I tried actually), but again the color will not be 100% flat, there will be a very slight unnoticeable shading.

[michaelwbell]

Guys, thanks again for the replies. Really handy stuff.

Svetlozar, the Self-illumination trick on a black material is extra nice. Very quick to setup.

Yeap it works(it was the last thing I tried actually), but again the color will not be 100% flat, there will be a very slight unnoticeable shading.

Definitely acceptable. The unnoticeable shading is actually kinda cool too. The shading might be a problem with certain types of geometry - I found with my original approach of using just the VrayLight MTL that certain occluded areas of the human mesh (inside of the man's mouth, nostrils, etc) were shading slightly darker. But I had flat MaterialID mattes that fixed this up very easily and quickly.


Again, big thanks guys. Great to see 3 different approaches, and so quickly too. Another reason why I love Chaos Group and the community in the forums. This thread is going into my favourites list.

[YoyoBoy]

I would just assign Object IDs to the figures, save out an Object ID channel, and deal with it in post.

[michaelwbell]

Thanks Geoff,

Yes in the end I used MaterialID - so that the character's hair had correct opacity map in the matte - and used the MaterialID mattes in post.
Original question was more focused on "how do you get the same result in the beauty pass while rendering quickly?"
The 3 methods here (self-illumination, ink&paint or override material) were all quite good.