Dirtmap / Ambient occlusion

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  06 June 2005
Dirtmap / Ambient occlusion

I somewhat know this is just a shadow map, but is there a way to control the shadows more? insert some light sources here and there? As of now it just does a shadow default calculation and no matter what I do with the lights the same shadows are generated...
  06 June 2005
It's nothing like a shadow map. It's a raytrace shader that detects other surface's within a certain radius from a point on surface.
Colin Strause
  06 June 2005
Oh ok. So can you control the shadows some way?
  06 June 2005

it doesnt matter what and how many lights u will place, it's only based on surface to surface distance.
only thing you can do is change the colors (can go above 1.0 or below 0.0 in V) and adjust spreading of the effect or clipping/max distances.
  06 June 2005
You can also map different textures to the dark color, in case that helps.
  06 June 2005
Some forms of AO are depthmap-based, GI_Joe being the most popular. Any sort of shader-based solution is almost certainly raytracing though.

I'm not sure you really understand what AO is for, though, if you're asking to adjust lights. It's a pass to visualize where ambient light would get trapped on a model.. you would mult it by the ambient lighting pass, then add the key lights on top of that. Should be more than enough shadow control... maybe I don't understand what you're asking, though. I have more than enough stupid moments.

Last edited by Bonedaddy : 06 June 2005 at 03:22 AM.
  06 June 2005

Here is a good explanation link about AO


Also i ve got very strange issue while trying to render the scene with both Dirtmap and DGS shader....Everything was fine until i set transparency to 0.5 instead of default 0 on DGS shader node....Render got slowed dramatically...i even couldnt wait till the end....however with Transparecy set to 0 everything ok

Anybody had the same issue ?
  06 June 2005
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