so...

[theginjaninja]

this comment from Strat:

 

"this helps beautifully with radiosity and gi (as we all know kids, 2 separate things)"

 

call me stupid.. but could someone please explain the differences?

[jackb602]

this comment from Strat:

 

"this helps beautifully with radiosity and gi (as we all know kids, 2 separate things)"

 

call me stupid.. but could someone please explain the differences?

 

As I understand it, global illumination is any rendering method that calculates diffuse reflections in a scene. An example of this is light bouncing off a white wall. Radiosity is one method of calculating global illumination, which creates a view-independent mesh of light values. FormZ and Lightscape are two implementations of radiosity. Photon mapping is another approach, which is what Cinema uses. Cinema finally changed the Radiosity tab under render settings to Global Illumination. Radiosity was actually the wrong term for Cinema's method.

 

Jack

[AJLynn]

That's pretty bizarre - all this time I thought I was doing radiosity renders and wondering why people kept calling it "global illumination"

 

Is this like the scheme mental ray uses, and does anybody know details of what they've changed to get the speed improvements in 9.5?

 

I've grown fond of the VRay approach, letting you choose what GI algorithms you're using, if only it worked with C4D it would be the perfect platform. I did a pretty complicated project recently using a bunch of interacting splines that C4D dealt with very elegantly and to get fast renders ended up having to export an FBX, bring it into Max and use VRay on it. Maybe FinalRender 2 will solve my problems.

[STRAT]

yup, stricktly speaking, radiosity is the diffusion and reflection of a material's surface properties. ie, each visible colour we see has a heat value assigned to it. and radiosity is the effect we see when another material reflects or absorbs this propertiy. usually shown up in colour bleeding in an image.

 

whereas gi is the effect of bounced and ambient environmental lighting, whether it be natural or direct. it's what gives renders the realistic depth of shadow.

 

radiosity and gi obviously go hand in hand, and are usually a consiquence of each other, but the line between them can sometimes be faded. you can render an image with one and not the other if your 3d app allows it. c4d does.

 

and sometimes a radiosity image over a gi image (or viccy verca) might be desirable.

 

infact, last time i look CGA had a load of papers about gi and radiosity on-line for your viewing.