VRay Light behaviour with motion blur

[loganai]

Hi All,

I'm have been running into a problem recently with my lights (vray rect) when turning on
motion blur.

The lights are constrained to a moving object and render fine, until I turn on motion blur,
at which point they seem to "disappear", i.e. no longer seem to cast light or be visible in
spec and reflection.

I have tried baking keys, parenting and multiple types of constrains in different hierarchy
setups (grouping), but all have the same result and the lights go from "on" to "off".

Has this happened to anyone else?

Any help would be greatly appreciated!

[pechart]

I think i noticed a pretty similar behavior in one of my scenes a few days ago. A rectLight constrained to an object which seems not to render from a random frame. It renders fine on my Mac but not so fine on our win7x64 workstations and renderclients. I'll try to provide the scene as fast as possible, but i'm stuck in a heavy project yet.

[loganai]

Thanks for the reply.

I have a bunch of them constrained to a moving object, however even when not constrained (baked) it still won't render correctly.

I should probably mention I'm running this on linux.

[vlado]

Can you get us a scene for this to vraymaya@chaosgroup.com so that we can check what's wrong?

Best regards,
Vlado

[loganai]

Hi Vlado,

I think I found the problem. I probably would have never found it hadn't I kept the lights
visible.

The lights were scaled in XYZ and not UV. As a result when you turned on MB it would
revert them to their UV size, i.e. 1/1. When they are scaled in UV everything works as expected.

Here's the example:

1. Lights scaled in XYZ / no MB



2. Lights scaled in XYZ / with MB



3. Lights turned up to show effect (notice small black rectangles)



4. Lights scaled in UV / with MB




Thanks again for the help!

[vlado]

Hm, odd. Can you tell me which build of V-Ray is this?

Best regards,
Vlado

[loganai]

Linux / 1.50.00.12190

I must say that I did try it on a newer build and still had that problem.