Shadow catcher, object intersection.

[xevious2501]

Ok, so im comping a snake into a shot. Using a simple ground plane as a Matte shadow catcher.
The snake will penetrate the ground plane. But instead of the shadow just being black, its creating a clear edge along the perimeter of where the geometry intersects. Also renders as a hole within the alpha.

Any ideas? fix or remedy?

[juanjgon]

Hi,

Sorry, but I'm not sure how to reproduce this problem here. Can you please send me an scene, as simple as possible, to try to reproduce it? I wonder if the problem could be related to the kernel node ray epsilon parameter ...

Thanks,
-Juanjo

[xevious2501]

Yup.. it is Ray Epsilon. Changing its value changes the size of the hole (line) BUT.. the inner hole remains with partial shadow when it should be 100% shadow.
And im not certain if the changes to alleviate the line will create problems with the rest of the render.

so its definitely a glitch , unless another function value will remedy the hole.

Now.. i understand that this shouldn't be much of an issue considering it a shadow being covered up by the object. But when compositing if your to manipulate the shadow its possible that the object will
be in a position that the presence of the hole will create issues.

[mikefrisk]

Could also be caused from the octane displacement. I think i've ran into this before and had to render each pass separately.