CGTalk - Masking geometry without transparency?

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victor

04-01-2004, 12:41 PM

Is there a way to cut holes with a texture that doesn't involve using the transparency channel of a material?

I have some trees which are a bunch of large polygons with a leafy transparency added to them (like how game model trees are made), but they take forever to render with ray traced shadows with both Maya Software and mental ray, becuase there are basically several layers of transparency for each tree (and it obviously gets worse when I have multiple trees overlapping).

Is there another way to get this effect without such a performance penalty?

alexx

04-01-2004, 01:02 PM

not that i would know of..

cheers

alexx

augustus

04-02-2004, 08:06 AM

Just an idea:

Select your light, then choose panels->look through selected. This creates a camera. Adjust view angle of this camera to fit light's cone angle. Give a transparency mapped black surface shader to leafs, a black surface shader to trunks, a white surface shader to all other objects. Render using new camera. Make leafs and trunks non-shadow-casting, in your original screne. Attach rendered image to color channel of your light and render.

This should work.

-Sorry for my terrible English. I hope you can understand what I mean.

Edit: You should use another light for trees.

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