Photometric Lights are bleeding through my scene

[caz2005]

Hello, this is my first post. I joined a while ago but have just been too mesmorised by other peoples work here and reading lots of solutions to problems I haven't had yet it's taken me ages to get around to this.

 

I've made a model of a house (3D Max) and all is going well until I started putting photometric lights around. The problem is the light is more or less passing through solid walls and creating light where there should be shadow.

 

You can see in the image that the light from the hall is coming through the wall and illuminating the cupboards and the space where there will be a washing machine later.

 

Obviously I have Force 2 sided checked.

 

Many thanks in advance for any advice

 

http://yfrog.com/09lightproblemj

Edited October 27, 2009 by caz2005

[tayrona]

Just max? or are you using any rendering engine?

[caz2005]

Hi there,

 

I´m rendering with MentalRay in Max

 

Cheers

[kippu]

do the photometric lights have shadow enabled?

[caz2005]

Yup,

 

I've tried with ShadowMap, Area, MentalRay, Raytraced.

 

The house is all one object too so there's no unwelded points or broken gaps.

 

Puzzling huh?

[Matt McDonald]

It could be related to the size of your GI photons. If they are too big, they can pass through objects. Mental Ray manages the size by default as a fraction of your total scene size (I want to say that by default they are 1/10th, maybe 1/100th of your scene size).

 

You can set manually set the size of your photons. Try setting them small, up the GI photon count and see if your problem goes away. But be careful, a ton of tiny photons can take forever to render so you'll need to come up with a size and a count that eliminates your problem, renders acceptably speedy and allows GI to enter some of the smaller spaces in your scene.

 

Generally speaking the GI (with final gather turned off) should look "smokey". You'll know it when you see it.

[SandmanNinja]

+1 with Matt. I call them "Flower Blooms" or "LSD Time".

I turn FG off and then set my photon size manually to 10cm, then 100cm, then 250cm and observe the results. When the "Flower Blooms" overlap enough to almost be a nice lighting solution but still have that smokey quality to them, that's when I turn on FG.

 

It's more art than science.

[caz2005]

Thanks guys, I'll give this a go.