Brazil & transparent planes

[Ian Jones]

Tell us more about what your trying to do... what render settinsg do you have? what else is in the scene? whats sort of materials / textures? have you tried a process of elimination and actually found that the transparent planes are causing the problem?

[Woodys3d]

Yes, are the planes for sure, I always have the same problem when I put some planes with some transparency. What I'm rendering is just a background of a scene, and there are just a few modeled branches and rocks, and then lots of scattered planes with texture to simulate the grass. Anything else has textures or strange materials, just standard materials, and the lighting is an skylight with hdri and 2 area lights.

What I'm looking for is some kind of parameter I can desactivate or tweak to make the transparent planes render faster and not to lose quality, cause the rendering time is really too large.

[Daniell]

Brazil is not very efficient with opacity map. Should be better to do a group of grass-shaped surfaces and then scatter that group. Or play with renderpass and scanline for grass only.
If you are using global Ill. try excluding grass from it.

Daniel.

[soulburn3d]

Well, to be more precise, raytracers are generally not as good at doing opacity maps as scanline renderers are. But also raytracers can do all these nice effects like GI / skylight / area shadows, all of which don't tend to work well with opacity mapped objects (wheras scanline can't do these effects), so first I'd remove any special lighting features you may have affecting the grass, using exclusion lists, the Brazil Utility material, or render your grass as a seperate pass with those features turned off to be reintroduced in the comp, or try doing grass with a fur system.

- Neil

[Woodys3d]

Thanks for your replies. I will try excluding the grass, cause the time is really too much and it's a background, and will be dark, so I will be able to solve it with traditional lighting with no much problems.

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