Radiosity

[manta]

I don't know if this has been done to death, but I think I need a lesson in GI techniques, most importantly Radiosity, stop me when I've said something wrong...

 

Radiosity is a process by which light is baked into your mesh, that is why it is view independent, lightscape was such an engine that did this, once the calculations are done, thats it, you can then do an animation with no further light calculations, it just renders...

 

Now, what about softwares such as C4d's AR and lightwave's Fprime, do these work the same way, cause supposedly they use radiosity, but I've never heard anyone say how great it was that they could render out animations easily and quickly...I assume Max's radiosty works the same way that lightscapes did, because it was based on it...

[Mario Pende]

Manta you said it all:)

Non of these new engines bakes light into mesh, wich for making animations is - a very F... long time!

Besides Lightscape in wich light is baked into mesh, I think theres also InSight for Max.

[STRAT]

no. radiosity isn't light baking. you can light bake, but thats not the general term for radiosity.

 

radiosity is the effect you get when a material's colour properties leak or bounce on to it's neighbouring object due to it's heat emmitance. this is different to GI, and nothing to do with baking. baking is just a general render technique that can be used for a host of effects, not just gi or radiosity.

 

i pressume ur looking for a nice fast way of rendering out radiosity/gi for animations?

[William Alexander]

Radiosity is generally a mesh based application of lighting. The subdivisions of the mesh determine the level of quality for the lighting solution. As opposed to 'GI" which is independant of the subdivions of the mesh for quality of lighting. More often than not view based solutions.

 

Radiosity in Max, the solution stays with the mesh. It's not baked...baking is taking the illuminance of an object, for lighting, and converting that data into a raster image which is 'mapped' as part of a material-imgae mapping...as a general rule. You change materials or lights the solution becomes invalid. Good for animation. GI using Mental Ray the lighting solution is based on that view, anything changes the solution becomes invalid. This is where true baking of the lighting to a 2D image mapping becomes mandatory for animations if the frame render times are toooo long.

[Mario Pende]

Yes, baked isnt the real word, stored is.

[manta]

Oooops, sorry I meant the light is stored in the mesh,

so was this an ineffifcient way of working, and was lightscape the only one of its kind ??

 

What are the drawbacks to working with this kind of radiosity ?

[John Dollus]

There are important limitations regarding radiosity. Radiosity in Lightscape and Max is based on an ideal diffuse environment. Translation: specular components of the materials are not considered in the raw calculations. The lighting solution is the same as creating simple gradients in each of the subdivisions in a program like Illustrator (oversimplification). The higher the density of the mesh, the smoother the appearance. In Max, these gradients are mapped onto the mesh based on the weighting of the vertices.

 

Baking usually refers to rendering out a direct view of a surface and reapplying that image as a texture map to the surface, giving it 100% self illumination and excluding it from further scene calculations. This can be accomplished with several rendering engines though the results can be rather unpredictable when it comes to complex geometry (think Bilbao museum)

[joseph alexander]

Are there software programs that are still investing in radiocity as a lighting technique?

[John Dollus]

Other than Autodesk...?

[manta]

Insight was mentioned, might want to check that out...

[Devin Johnston]

I just purchased Vue 5 Infinite, its rendering engine will use both GI and Radiosity and it also supports baking. I've only had it for about a week but from the tests I've done I'd say that its engine is probably better than the Max radiosity engine in that you don't have to process the radiosity solution before you render, and Vue gives you an interactive preview of your scene which I find very addictive. The down side is that you have to purchase additional render node licenses, it only comes with 5 but I'm pretty impressed with what I've been able to do with just 5 licenses.

[Mario Pende]

Is baking painfull? Once baked, can it be used for entire animation?

[STRAT]

Is baking painfull? Once baked, can it be used for entire animation?

 

yeah, but the baking process can be a major pain in the butt, and, if you then change any materials or objects you need to re-bake.

 

like Ernest, i've started hy-brid baking. that is, only bake some of the larger beefy elements of a scene that are fairly the major contributors to slowing down the gi process.

[Mario Pende]

Lightscape still in the lead!

[Digital_Assassin]

You can bake lighting with 3dsmax, in the menu at the top go to Rendering->Render to Texture, theres a lighting map option in there along with various others.