light leak

[mynmonic]

I made a sofa model with a built-in light box that the light shoots up through the glass.

 

But for unknown reason in the render as you can see in the image, the light goes everywhere through the sofa foam, to the sofa bottom, under the seat cushion etc.. as if it's a sphere light source without casting shadow.

 

I'm sure the plane vray light in the light box is placed inside the sofa while the transparent above is the only exit for light, and it's set to cast shadow.

 

Before I'm able to upload the max model for further investigation. Any chance that there's a well known mistake to cause this problem and I don't know of?

 

Please advise, thanks.

[Cad64]

Make sure you check the "2-Sided" option in the material you use for the sofa cushions.

[mynmonic]

thanks cad64.

 

I'm using the vray material for the sofa cushion, if you are saying the "double sided" in vraymtl option, yes it's checked on default.

 

And I've tried to on/off everything in that option like, trace reflection/refraction, reflect on back side. the problem doesn't go away.

 

probably i send you the max file.

[Cad64]

I will take a look if you send me the file, but I don't use Vray. I've created light boxes before using Mental Ray and I always check the "2-sided" option in the material editor.

[Cad64]

I received your file, but as I said, I don't use Vray so I can't really help you with your problem. But I did render your scene with Mental Ray using the "2-Sided" material and the result is below. I'm sure Vray materials have something similar.

 

Take a look at this tutorial: http://www.vrayelite.com/lightbox.htm

[mynmonic]

thanks cad64. the link you posted is really good, it consolidate some of my concepts. for the light leaking problem i'm still working on it, and i've found an interesting thing. under the same setting, when i zoom to very close and render. it looks better, at least the unwanted light on the floor disappear (although the light under the sofa cushion persists).

 

I'm guessing if there's a relatively object distance (compare to the view size) causing the problem. I will go on and find the clue, and let you know when I work it out.

[minks]

what kind of color mapping are you using? try reinhard with 0,5 burn value. also you could dial down a G.I amount in the vray properties for the sofa.