Radiosity - light leaks

vru · October 25th, 2004

Hi
I have been trying to get good results with radiosity for a long time now. I am getting huge light leaks. I have all the edges of wall and ceiling meeting. I have used closed spline, extruded it and converted into mesh for my walls, ceiling and floor. I thought regathering will take care of the leaks but that is not happening.
There are other problems, like dark ceiling and noise. The cloth texture has artifacts even with tighter mesh and regathering. Anti-aliasing is not right at ventilator frame and some wall-ceiling edges.
I have also noticed that the bump mapping looks different in different views. So I cannot use the same radiosity solution. I have to reset the bump and calculate the solution again.
Attached are some views, wireframe view and radiosity settings. I am using IES Sun and IES skylight.
Please advice.
Thanks
Vrushali

doujay888 · October 26th, 2004

Quote:

Originally Posted by vru

Hi
I have been trying to get good results with radiosity for a long time now. I am getting huge light leaks. I have all the edges of wall and ceiling meeting. I have used closed spline, extruded it and converted into mesh for my walls, ceiling and floor. I thought regathering will take care of the leaks but that is not happening.
There are other problems, like dark ceiling and noise. The cloth texture has artifacts even with tighter mesh and regathering. Anti-aliasing is not right at ventilator frame and some wall-ceiling edges.
I have also noticed that the bump mapping looks different in different views. So I cannot use the same radiosity solution. I have to reset the bump and calculate the solution again.
Attached are some views, wireframe view and radiosity settings. I am using IES Sun and IES skylight.
Please advice.
Thanks
Vrushali

Well, Im having this same problem with radiosity each time i use daylighting
which causes light leaks. Im joining you for this ordeal, hope someone with a good heart can help us.

Asking for help,
Dennis

tcorbett · October 26th, 2004

Radiosity in MAX/VIZ takes the value of light at each vertex and blends it across the face. In these examples, you probably have your wall extending to the edge or beyond the other wall, causing the light leak.

3 ways to control this:

1. Crank up the subdivision count in Radiosity. Instead of 3 feet, use 1 foot. This will also increase your calculation and render time, but you will get a better spread. You can also apply the "subdivide" modifier only on specific objects to acheive the same effect.

2. Use the "slice" modifier to "refine mesh", and place the slices within that wall intersection. Of course, now no light will be hitting that vertex, and you will see an opposite effect - kind of a "dark leak".

3. Build your walls & ceiling more precisely. Also consider putting large box overtop of your model, to act as kind of a sunshade for everything that is not a window.

vru · October 26th, 2004

Thanks for the suggestions.

I do think there is a problem with the modelling of walls and ceiling and how they meet. I have gone through some other posts here talking about it. But I did not understand what is the right way to model.

Could you please see the attached wireframe image of my model and comment on the modelling issue?

Thanks a lot.

Vrushali

vru · October 28th, 2004

Hey Dennis

Let me know if you have any suggestions.

Vrushali

Saturn · October 29th, 2004

My only thought would be to set the filtering up to like 3 instead of 1. Oh, by the way, you don't have to run your solution up so high. You can get good results if it is set to 90 or so.

October 26th, 2004	#3 (permalink)
tcorbett Senior Member Join Date: Aug 2003 Location: Pittsburgh, PA Age: 31 Posts: 142 Name: Tom Corbett	Re: Radiosity - light leaks Radiosity in MAX/VIZ takes the value of light at each vertex and blends it across the face. In these examples, you probably have your wall extending to the edge or beyond the other wall, causing the light leak. 3 ways to control this: 1. Crank up the subdivision count in Radiosity. Instead of 3 feet, use 1 foot. This will also increase your calculation and render time, but you will get a better spread. You can also apply the "subdivide" modifier only on specific objects to acheive the same effect. 2. Use the "slice" modifier to "refine mesh", and place the slices within that wall intersection. Of course, now no light will be hitting that vertex, and you will see an opposite effect - kind of a "dark leak". 3. Build your walls & ceiling more precisely. Also consider putting large box overtop of your model, to act as kind of a sunshade for everything that is not a window.

October 26th, 2004	#4 (permalink)
vru Member Join Date: May 2003 Location: Starkville, Mississippi Posts: 56 Name: Vrushali Palamwar	Re: Radiosity - light leaks Thanks for the suggestions. I do think there is a problem with the modelling of walls and ceiling and how they meet. I have gone through some other posts here talking about it. But I did not understand what is the right way to model. Could you please see the attached wireframe image of my model and comment on the modelling issue? Thanks a lot. Vrushali

October 28th, 2004	#5 (permalink)
vru Member Join Date: May 2003 Location: Starkville, Mississippi Posts: 56 Name: Vrushali Palamwar	Re: Radiosity - light leaks Hey Dennis Let me know if you have any suggestions. Vrushali

October 29th, 2004	#6 (permalink)
Saturn Senior Member Join Date: Dec 2003 Location: Jacksonville Age: 29 Posts: 472 Name: Jason Matthews	Re: Radiosity - light leaks My only thought would be to set the filtering up to like 3 instead of 1. Oh, by the way, you don't have to run your solution up so high. You can get good results if it is set to 90 or so. __________________ Jason Matthews

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