Light passes through object with Menatl Ray

[Teratron]

Hi everyone,

 

I’m having a problem with my lights. The hot spot is shining through to the wall behind them even though they are encased in a fixture. Since the have shadows enabled they shouldn’t put a bright spot on the wall right behind them but its there. I am using Mental Ray GI and FG, I don’t seem to have this problem with Final Render or Scan line but I would like to use Mental Ray and figure this out. I have tried quite a few different things including.

 

- Upping the density on my fixture mesh

- Moving the Fixture away from the wall since its actually going through it.

- Tons of different lights and shadow settings

- Tons of GI and FG settings

 

Right now I’m using photometric linear lights but I get the same thing with Omnis and all the others.

 

Here are some Images.

[DennisHolland]

Hi,

 

First you must turn on 'shadowmap' instead of any other setting. Delete all pre-calculated regatherings or (advanced) lighting solutions and just try again. It should work fine....

 

Dennis

[Teratron]

Hello

 

Thanks, but I have shadow map enabled (I assume your talking about Render Scene/Shadows & Displacement/Shadow Maps - then the check box that says Enable.)

 

Also every thing is set to rebuild and the lights have shadows enabled

 

Or were you talking about something else?

 

Thanks again

[pixelperfectg]

can you post a partial scene? Or at least a screen grab of the light settings.

 

Jeff

[pixelperfectg]

Actually before doing that light setting post, you might want to enable the GI radius option and try a render or two with that (keep reducing until the photons do not leak from the light fixture)

 

Since that's disabled maybe MR is just guessing the wrong size for the photons.

[William Alexander]

First before going down the twisitng MR settings path, please post a close up wire frame, 640x480, of the light box/light/wall geometry.

 

Shadows turned on for the light?

Have you tried a 2 sided material for the light box? (sometimes helps)

Is the light box a "shelled" object or just a polygonal box?

Does the box intersect the wall? I can duplicate your exact results when it does

Jeff's suggestion about decreasing the photon diameter will resolve the problem is the above is correct, imho

 

WDA

[Teratron]

Hmmm, thanks guys but

 

The GI radius thing helps but the point i have to decrease it to seriously diminishes the amount or quality of the photons in the scene, I guess I could possibly counter this with upping the amount and multiplyer but I'm not sure how well that would work.

 

The fixture does intersect the wall and moving it away helps but it dosent completly fix the problem unless I move it way far away, so even when its not intersecting it still hapens, though drasticly reduced. I think this may be the real problem though.

 

The 2 sided material is a good idea but dosent semm to change anything

 

the lights have shadows enabled

 

Its just a poly box with a few bevels to hollow out a side for the light to fit in. I have tried a shelled vertion but dosent semm to help. Will try again though. The normals should all be facing the correct direction to block the light.

 

Like I said I think the real problem is that the box intersects the wall, though I would like to think that MR photons would not be so prissy as to freak out about it, bc I dont seem to have the problen in FR or LT only with MR GI.

 

 

thanks again