Is this a ray shadow bug?

Tell me please, is this is a ray shadow bug?

I render this scene: (33kb)

and give that strange result for all types of ligh (e.g. sun, lamp, etc) when ray shadow used, and give right result for buffered shadow or shadow turned off.

Depends of camera position this artefact can different kind:

Or with no artefacts at all:

Any advice?

By the way, I tried to remove dobles and recalculate normals. Nothing chanhges.

Also I test it for the next builds:
2.36 offical
2.40 offical
2.40 bf-blender SSE2 (another kind of artefacts but it take place)

I’ve had this problem before. The faces on your mesh are so close together at such a fine resolution that the camera is having trouble distinguishing between them. Move the camera even a little and the abberation is fixed. To solve the problem you’ll likely have to either add more distance between the faces or remove one or the other. You might try scaling up too, but I believe that’s the problem. The matter was reported to the bug tracker and was determined to be a non issue so you’ll have to work around (if, in fact, I’m right about what’s going on).

Ok, thank you. When I make pretty much thick of this model it become looks
fine. But it is bug I think too.

It interinst too, that this model with RayMirrow and no shadows (turned off shadows in render options) have the next artefacts too:

And without flipping normals it looks so:

And so, there is an another way to fix it: Just a make camera Clip start and clip end distance less. And its work too, but unfortuntly not so helpful.

Biasing problem still chase me. When meshes are near each other somethimes its rendered wrong. Some meshes could placed in wrong z-order. I dont know why.

Is there any way to make much or less precision for the rendering? it would be great.

Yes, didn’t think of that. Most settings of that nature in blender allow you to go beyond the optimal to a point that will cause artifacts. Set the bias up from 0, good idea. Have to remember for the next time.

Where to set bias to zero? And is it help me to render mirrors correct?

Sorry, bias is for shadow mapped lamps. In lamp properties. Camera is clipping. Set clipping up to .1 or something is what you were saying right? In the camera properties F9. My error. Apologies.

Noone can comment it more?