Max 5 radiosity help

[Brian Cassil]

My company finally upgraded me to Max 5 which I was very excited about and of course the first thing I wanted to dive into was the radiosity stuff. I have been using FR stage-0 which I actually like but I want to have a firm grounding on other rendering engines so I can use each to its own advantage.

 

I have gone through the tutorials which I did not find that usefull but everything seemed to work fine so I set up my own scene to start testing the capabilities of radiosity.

 

Here is a screen capture of the radiosity solution:

 

 

The box is about 12 ft. squared, I kept the reflectance of the materials within reasonable range, and used a single photometric area light to illuminate the scene. At this point I did think it was strange that I had to set the intensity of the area light to 10,000 cd. to get the light level where I wanted it.

 

So now it's time to render and to my horror, this is what I get

 

 

And yes, I did have "use advanced lighting" checked in the render dialogue, but just to see if there would be any difference I unchecked it and rendered this

 

 

As you may see the only difference seems to be a little bit of light on the under side of the spheres in the use advanced version.

 

So what am I missing? I'm guessing it has something to do with the rendering options as the radiosity solution in the viewport looks ok. However, I also considered that it could be a problem with my units scale but I've played with that and it seems to be set up fine, I have system units set to inches and when I change that I can see the changes immediately reflected in my viewport.

 

Any help we be greatly appreciated.

[abicalho]

Your materials probably have a black ambient color and a colored diffuse color.

 

Make sure diffuse and ambient are the same.

 

Radiosity works by adding the indirect illumination back on the ambient color slot of a material, and if that is black, indirect illumination will not be rendered.

 

There's also a sample script available in the 2nd CD that automatically copies Diffuse into Ambient for you.

 

Hope it helps,

 

Alexander | discreet Quality Engineer

[Brian Cassil]

You are absolutely right! I had actually read in one of the tutorials I did that the ambient color should be set to black. However, that tutorial was intended for viz and it is over a year old so maybe things are little different for max in that regard.

 

Thank you so much for the quick reply. Now I am still a little perplexed by what seems to be the extremely high settings for my area light or does that seem about right to you. It would really be nice if there was some kind of guide for what the luminance settings for standard light types should be.

[nuno]

hi brian,

for a comparsion between your light values and common lamp values go to the help | search | and type "common lamp values"... there... found it?

 

now...to adjust the brightness for your image, i think this can solve your problem.....

go to "environment" dialog box ... choose "logarithmic exposure control" check the "active" field, then on "physical scale" type the same value you have in your light (in your case, 10000).

 

i am not sure if this can solve your problem, but i think i understood it well....so...tell me the results when its done.

 

best to you,

nuno

[Brian Cassil]

Thanks for pointing me to that table on the help menu. It will come in quite handy I'm sure.

 

About the brightness, I wasn't as concerned about it being too bright as I was about that number 10,000 seeming kinda high. But after looking at that list it falls within some of those ranges.

 

Muito obrigado amigao!

[Ricardo Eloy]

Hey, Brian!

Sometimes, only adjusting the brightness of the image you can solve this kind of problem. In the same place you set the Physical Scale (in case you`re asking where). If I'm not mistaken, it's set to 65 as default, which is very low. So you can make it as high as 80, I don't know. It may sound dummy, but it's a quick way of getting things done, sometimes.

BTW, in case you didn`t notice, not only you and Nuno speak portuguese in this thread. ABicalho is also brazilian! So, this is quite a portuguese speaking thread!

[]

Rick

 

[ April 04, 2003, 12:47 PM: Message edited by: Rick Eloy ]