Stencils break with environment fog

[danklife]

So I got my render nodes working and fired off a render which looks amazing after going for one hour. Took three with Modo's default renderer with extra nodes and did not look nearly as good. BUT I think I found a bug where stencils leave a “ghost” of the polygons when V-Ray Environment Fog is added. Check out the screen shots. The AO file is clean as clean can be but the main render has a ghost of the polygons. Thoughts?

[boyan]

Hey danklife,

Thank's for your post. I've been testing but could not reproduce the issue with vray fog and stencil map. Hope my workflow might be suitable for you.

BR Boyan

[vladimir.nedev]

So I got my render nodes working and fired off a render which looks amazing after going for one hour. Took three with Modo's default renderer with extra nodes and did not look nearly as good. BUT I think I found a bug where stencils leave a “ghost” of the polygons when V-Ray Environment Fog is added. Check out the screen shots. The AO file is clean as clean can be but the main render has a ghost of the polygons. Thoughts?

Can you post the scene or send it to me ?

Greetings,
Vladimir Nedev

[danklife]

Happy to send it to you Vlad. WeTransfer is inbound. I am testing it some more today and I think the difference is I used Emission Color to get my fog where Boyan used Fog Color. I am testing with just using fog color but it's blowing out my scene so I have to learn what I am messing up.

[vladimir.nedev]

Boyan has his color swatches in a different mode, where 255 is the maximum.
So, his 217 translates to something like 0.85 in your case.

Edit : we probably need to internally clamp the fog color to 1.0, I am not sure whether values above 1 make sense.

Greetings,
Vladimir Nedev

[danklife]

I just tweaked the fog settings to not use Emission Color and it appears the stencil ghosting is worse? Camera right near the center area.

That said, holy smokes did this render fast.

[EDELVIZ_ARCH]

I think there is a big problem that Stencil is evaluated as transparency (so being evaluated as transparent but as refraction steps, for reflection- basically for the non diffuse components) and not as stencil (which really removes the elements from rendering and does not evaluate them for any components).
Since you have a lot of leaves with transparency stacked one in front of the other, the maximum refraction depth will be exhausted after 5 steps (unless you have changed it manually in the V-Ray material) - so I think you need to increase the refraction steps - for this to go away. But that will drive up the render times.

Vladimir, is there a way to replicate the stencil effect in V-Ray?

[danklife]

That is interesting Edelviz, thanks for that theory. I'm jumping onto a paying gig, but I will test that out later in the week.

Thanks again.