Strange Plant Shadow

[Marc Chaumier]

Hi roy, I rendered an aerial picture with nXt plant, and I have noticed a strange behaviour of the shadows of one sort: the cypress. Do you have an idea of what is happening? I send you the nXt tree, if you got the time...

[Roy Hirshkowitz]

Is it a perspective or orthographic projection?

[Marc Chaumier]

perspective, with point of view very high (~6km) and a lens of 1000 (!) to simolate an orthoview, but I've seen that in the tree editor, the shadow of the cypress is strange to. Perhaps does it comes from my leaf file (png)...

[Roy Hirshkowitz]

No-- this is very likely a precision problem. Your camera is too far away to reliably resolve all of the objects. This is a case where you could try an ortho projection. Otherwise you're running into a limitation of the software.

[Marc Chaumier]

Thanks, Roy. I will try ortho.

[Marc Chaumier]

Sorry, Roy, the problem remain that I can't explain... Very strange shadows, in ortho or perspective, far or near, it doesn't matter. Here is the same picture, lite and higher resolution. Just take a look, I've never seen that.

[Roy Hirshkowitz]

You can send it to me-- or you can try a couple of things first.

Increase the refractive bounces-- it's a very thick tree and the shadow ray may not be making it all the way through. Thinning out the tree may also help-- it's probably thicker than it needs to be.

As far as precision goes-- check your camera (eye) location and your drawing points. Make sure you're not introducing any large coordinates here. I don't think it's precision anymore based on this thumbnail-- we'd be seeing more generalized artifacts.