CGTalk - mib_fg_ambient

Gal

03-16-2006, 05:20 AM

hey i've been trying to find a way to get AO that calculates light values, which is what mib_fg_ambient_occ was meant to do i guess. however it's not just a simple network in order to get that.
basically i want to "mask out" the AO multiply effect from areas where light hits surfaces directly as it does in real life(or by using pure FG byit self with a low radius without any AO).

i have been trying to get it with normal AO by sampling light/illumination values use an ADD function on the normal mib_ao node which kinda works BUT it still leaves me diffuse shading from FG on the surface, which i dont want. i want to mask that out too.

i dont have a minute now to show screen shots but i hope someone understands this very simple concept. i'm sure someone has done this by now:
ambient occ only in shaded areas and not in directly illuminated areas.(why do this and not just use FG for the same result? because FG is slower and flickers for animation not to mention it bleeds light).

anyone have any network connection ideas?

magsnus

03-18-2006, 10:39 AM

Hey Gal!
Have you had any further luck on this topic? Ive been trying to achieve similar effects earlier but havent really gotten anywhere. Tried Daniel Rinds dirtmap shader and also the Mega_TK shaders directional settings but could only get it to work under mac and not pc, results were quite nice though.

Gal

03-19-2006, 03:23 AM

the only AO node that will calculate based off light values is the mib_fg_ao one but it will act like a normal AO function based on proximity unless you add light info to your network to subtract AO out but you are left with the diffuse shading of the object. i couldnt find a way to get the shading out too. since surface shaders dont calculate light values you cant use a surface shader.

this is a very simple idea and i'm sure someone managed to do this before. because adding an AO pass to multiply over directly illuminated areas on objects looks really bad and unrealistic.
i cant be the only person who has been trying to do this.

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03-19-2006, 03:23 AM

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