VRayShadows (or other element) - include backfaces?

[duke2]

I'm trying to get a straight matte of shadows, including backfaces. Is there a way to do this or do I need to render the scene twice (with and without shadows) so that I can combine it with RawLighting?

Notice how in the example below, The backside of the large sphere isn't included in the Matte Shadow element. How do I include it?

[Svetlozar Draganov]

The shadow information on the backside of the large sphere is missing because nothings casts shadows on that area.
It is just non illuminated area and rendering it with and without shadows will generate the same result.

I don't think it is possible to extract such mask directly from V-Ray, but it might be possible to get it combining different render elements.
Would it be possible to send us that scene and an image which outlines the mask you are looking for and I'll try to figure something out?

[vlado]

Actually I have a texture plugin that does that; you can use it with the VRayExtraTex render element to get that effect. I can upload the texture here... which 3ds Max version are you using?



Best regards,
Vlado

[duke2]

That would be great! I'm using 2014 64bit with VRay 2.4 (apparently 3.0 soon but who knows).

[duke2]

As of yesterday, 2015 with VRay 3.1 (whatever the latest is)!

[vlado]

Ok, try dropping this into the vrayplugins folder; you should get a texture called VRayMatteShadowTex that you can use in a VRayExtraTex render element.

Best regards,
Vlado

[Raven]

This looks very helpful, any chance of getting the 2014 version Vlado?
Thanks

[Dave_Wortley]

This looks very helpful, any chance of getting the 2014 version Vlado?
Thanks

++1....................

[vlado]

Out of curiosity, what do you use it for? Would it be better, for example, to make the regular matte/shadow render element to behave in this way? Or should this be an option?

Best regards,
Vlado

[Dave_Wortley]

Out of curiosity, what do you use it for? Would it be better, for example, to make the regular matte/shadow render element to behave in this way? Or should this be an option?

Best regards,
Vlado

Won't know till I play with it We always like to have extra masks to play with.

[Dave_Wortley]

I seem to recall something once upon a time try to use Falloff with light/Shadow mode, and not being able to do what I wanted, but this mask would.... no idea what is was now though...

[duke2]

Out of curiosity, what do you use it for? Would it be better, for example, to make the regular matte/shadow render element to behave in this way? Or should this be an option?

Best regards,
Vlado

We use it for a view shed analysis, so the shadow/hidden faces are what you don't see. We do this with a spotlight as the viewer, and the element to overlay a colour or graphic to indicate what you don't see in plan view.

[duke2]

Vlado, would you be able to do a build for Max2016/64, VRay 3.2? Thanks in advance!

[vlado]

Yes, will see what can be done about it.

Best regards,
Vlado

[vlado]

Here you go. Sorry for the delay.

Best regards,
Vlado