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deltaindigo
12-19-2006, 12:09 PM
Hi ,
I'am totally new in compositing and I've seen a lot of people that use a bent normals pass for compositing ( in Photoshop for example) in addition with other passes ( AO, Beauty,Shadow..e.t.c). I was wandering if someone could explain what is the main pourpose
of this pass and how to use it.Thank you !

Ash-Man
12-19-2006, 02:43 PM
here is a tutorial I found

hope it helps
http://www.andrew-whitehurst.net/amb_occlude.html

deltaindigo
12-19-2006, 11:04 PM
tanks for reply Ash-man,
I saw the tutorial but it does't cover this part(compositing the bent normal pass in photoshop or any other aplication)
Until now (although I don't know if is right what I'am doing) I broke the bent normals pass in 3 seprate layers (one for each channel - R G B, I presume that is an easy way to do that:) ) and put those gray layers on top of the base image trying to figure out what is the best solutions for blending mode of the layers.I 'am kind of begin to understend what those layers do (r g b) but again ,I am not sure if is corect.
So, if anybody knows this procedure please post few words,I ll appreciate any reply
Thank you :)

Digidim
12-20-2006, 09:43 AM
...found a video tutorial covering the use of a bent normal pass for "2D Lighting" using shake:

http://www.maxlith.f2s.com/andreas/2DLighting.mov

hih

Ash-Man
12-20-2006, 05:25 PM
thanks for the link Digidim
I think that ashwer the Q
I'm also sure that I saw it here in a thread...it was an architrectrue model

but I cant find it ...:D

techmage
12-20-2006, 08:54 PM
Fusion 5 has a node built into it designed to deal with normals and bent normals. Photoshop has nothing in it to deal with bent normal passes or even normal passes and I don't know if any plugins exist for it. Personally, I wouldn't try to use passes like that in photoshop.

Another use for bent normals is to bake them to the object and use them as a lookup to a spherical eviroment map to fake GI on single moving objects in animation. Mental ray has a node called mib_bent_normal_env which will use bent normals in that way. Or you can take the bent normal passes into Fusion and try to accomplish the same thing. The fusion node will take bent normals and do a spherical lookup to fake GI in the same manner. It works fairly well, I have not used either method in production though so I really don't know which workflow will produce better end results.

You can also use bent normal passes or just normal passes with the fusion node to relight objects. But of course your not going to get shadows and I really never found this to have any advantage over just using diffuse and specular passes for lighting and re-rendering those passes if you want to change something.

MaNdRaK18
12-21-2006, 11:28 AM
Fusion 5 has a node built into it designed to deal with normals and bent normals.

Can You please tell me what's that node?

techmage
12-22-2006, 06:50 AM
Can You please tell me what's that node?


Filter>Deep Pixel>Shader

Set reflection to 0 and play with the diffuse/specular settings in combination with equator angle/polar height and you can light things with a normal pass. If you plugin a bent normal pass, set diffuse/specular to 0 and mess with reflection, set it to spherical and plug a enviroment reflelction map into it, then you can have it fake GI like mib_bent_normal_env nodes does.

it requires alot of tweaking though and from my experience it never really gets as accurate as if you were to actually use mib_bent_normal_env, but it is definanetly fast

MaNdRaK18
12-22-2006, 01:42 PM
Thanks A LOT, Rygoody - extremely precise and helpfull info.

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