Radiosity needs lights?


(DAK) #1

I used to think I understood radiosity. But playing with blender, as I am reading these tutorials you have to add a light to see your own radiosity?
If radiosity is light, what is the point of not seeing it unless you add another light, disruping the lighting in the first place?

I am very confused here.


(VelikM) #2

Radiosity is self illuminating, you still need lamps/spotlights for shadows and objects that don’t have radoisity. The pic is a sphere with radiosity, with a reflection map, rendered without any lights.
http://www.michaelv.f2s.com/misc/radiosity.jpg


(DAK) #3

Ok thanks, I will try and experiment some more. I am also puzzled by what those multiple boxes represent when the calculation is about to start. There are like 4 squares.


(RipSting) #4

The boxes represent the distance light will travel and that sort of stuff. You need to have at least one “Patch” for the object to be lit. That is, at least one face with a material with Emit set higher than 0.0 The larger the face, the brighter the light will be also.


(DAK) #5

Great. I have never seen this explained in any tutorial (can someone make one?), but I will keep an eye on it and maybe figure it out over time.
I noticed that light tends to bounce only 2x in my tests. I placed a half spere in a box and had it emit light. The llight hit the ground, then bounced up, but stoped halfway up the sides of the box. I used to think the light would bounce around as many times as you wanted.
Maybe I need to change some more settings, too many buttons, not enough documentation.