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View Full Version : Looking for Gi and GF explanation for dummies


sixtees
03-26-2010, 02:07 PM
Hi everyone, sorry for my english i hope you understand my question. ;)

I'm looking for someone who can explain the global illumination and final gathering to a newbie.

From the mental ray tutorial of digitaltutors.com i learned so far, that the global illumination is changing the way how lights in 3dsm works.
So, GI lets the photons coming from a lightsource reflect on all materials and objects on it's way, so that they take some color informations of the objects and paints the point where the photon dies.

-But what does final gathering?
-When should GI and FG be used? Always?
-When i use only one of this two tools. i don't really see a big difference.
And what is the benefit when combining both?

Thank you

Fingus
03-27-2010, 07:43 AM
Global Illumination and Final Gather are two different ways of calculating the results of light bouncing. GI will simulate the way light actually bounces by emitting photons from the light source and have them bounce off surfaces. As far as I understand FG on the other hand uses the geometry in the scene as light sources and samples per pixel to simulate the effects of global illumination. GI is more accurate, FG is more efficient, and you can combine both for the best of both worlds.

I googled Final Gather and found this explanation in Autodesk's documentation. It seems to explain it much clearer than I can.

http://download.autodesk.com/us/maya/2010help/index.html?url=mrfm_Lighting_Final_gather.htm,topicNumber=d0e562454

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