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View Full Version : Final Gather understanding!

Dyonisos123
08-16-2005, 05:16 PM
hi,

i just thought to ask you some questions about the basic handling with final gather maps
of mental ray when it comes to rendering.

i always wanted to know, when i have to recalculate the fg map in the testrendering state of my scene.

so i have wrote down some questions:


do i have to recalculate the fg map in mental ray, when:

a) i did some changes in the sss fast skin material
b) i did some changes in one of the other kind of materials ( maybe tranclucency )
c) i add one more light to the previews rendered scene
d) i render now from a different view or camera angle
e) i take away one light from the previews rendered scene
f) i add one more object to the scene
g) i take away one object from the scene
h) i change the position of one light
i) i change the position of one object in the scene
k) i want to increase the rendersize
l) i want to decrease the rendersize

i know these are a lot of detailed questions, but they can save a lot of time if you know them ...

any suggestions?

thx

Michael
playmesumch00ns
08-17-2005, 08:55 AM
All yes except

k and l
bt3d
08-17-2005, 09:40 AM
If you use 'view depended' sampling K and I might be also effected, or am I wrong?
playmesumch00ns
08-17-2005, 04:09 PM
No I think you're probably right.
tweeeker
08-20-2005, 10:04 AM
regarding d) I don't know what sw your using, but with Maya 6.5 it's easy to 'append' the final gather data from a new view into an existing finalgather file. Once you think you have all the data you need for the various views, set 'Rebuild Final Gather' to 'Freeze' to prevent mr from adding any more data to the file.

regarding a) & b) personally, I often dont rebuild the fg file after minor shader tweaks as the change in irradiance would be minute. Don't have the time or patience.

But strictly speaking the previous answers are correct i.e it *always* needs recalculating - which is why for me occlusion is so much more useful.

T
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