warning: Scene bounding box is too large, ....

[CCS]

I get this in my VRay message box at render time:
"warning: Scene bounding box is too large, possible raycast errors"

Current scene is large, but it's a fairly typical size for me. Is there something I should do to avoid this error? Or is it something I need to even be concerned with?

Some details, FWIW:
Scene is in inches. Project site is about 200'x800', and contains 4 large buildings. I also have a cylinder (about 5000' across, I think) with a background mapped to it. I have excluded the cylinder from generating GI and from generating or receiving caustics. Terrain and buildings are linked in from AutoCAD.

Any thoughts?

[ezrhythm]

I have the same message showing on every render... so far i didnt have any problems.

[CCS]

I don't think I'm having problems either - that I know of.

I'm just wondering if render times are being affected by rays flying off and bouncing 3 miles away and getting lost. Or something like that. (Hope I didn't get too technical.)

[vlado]

VRay puts this warning because when you start working with large numbers, there can be severe loss of precision.

For example, when working with single-precision floating point numbers, 100000.1-100000.0 will produce 0.101563 as a result. If your generic units are centimeters, for example, VRay will not be able to distinguish between an object that is a kilometer away from the origin, and a kilometer and one milimeter from it, so you may get some problems if you have small details in this place. The effect is very much like using a low-precision z-buffer when rendering with OpenGL.

Of course, things are relative, and if your scene is large, but the details are also large, then there is no problem.

Best regards,
Vlado

[CCS]

So, if I understand correctly, fine detail (to 1/8", let's say) near the origin would still be interpreted correctly, while similar detail a mile from the origin would not be?

[vlado]

So, if I understand correctly, fine detail (to 1/8", let's say) near the origin would still be interpreted correctly, while similar detail a mile from the origin would not be?

Yep, exactly.

Best regards,
Vlado

[meanadam]

I just started to get this warning - added about 22,500 polys to the scene (1 object). Now my light map crashes with motion blur on.

The new object is in motion....
??

a

[vlado]

I just started to get this warning - added about 22,500 polys to the scene (1 object). Now my light map crashes with motion blur on.

The new object is in motion....
??

a

That's probably a different thing; it would be useful if you can send me your scene to vlado@chaosgroup.com so that I can take a look.

Best regards,
Vlado