Reflective Occlusion?


Hey there!

I am trying to do Reflective Occlusion, instructions I found from here:

You have to scroll down a bit to find right spot.

First I was confused about the Maya’s surfaceShader, I mean XSI doesnt have node like that and I started to wonder what may be equivalent shader in XSI for that surfaceShader. After I read the descriptions, I thought that this node is not important at all. As I understand, it should be node for allowing you to connect tree into material node in maya, just for piping.

I am using Dirtmap shader. First I thought I am getting somewhere but then I found out what may be the problem. Dirtmap allows diffuse occlusion around surface normal. But I was unable to find option in Dirtmap what allows to do diffuse occlusion around the reflection direction of eye ray.

So how can I do reflection occlusion in XSI? Can I use dirtmap for it or I need some other version for occlusion shader where something like this is implemented?


I’m not sure if this is technically doing the right thing but doesn’t adding dirtmap to the reflectivity channel work? top thing rendered using the render tree and the bottom one has diffuse removed from both channels.


Thx rube. Thats a very good idea! I tried different approaches but they didnt want to work out at all. Seems like your is exactly The Thing. Dunno about technical background, would be cool if someone could affirm it.

As I posted same thread also in XSibase I got some good news from there too. One guy confirmed that To_Light shader pack is fully functional under xsi at last. I checked out it couple of months ago but it had problems with some shaders. There should be all included what one needs, diff occ, ref occ, and most importnatly diff occ with transparency support. Will test it out if I find some free time.

thx again rube!


ehy splin use this one to ctrl reflection occlusion.

  don't be scared by the various parameters, with the
 defaults it acts like dirtmap (and any other occ shader 
 outthere), but should be a tad faster 'coz it caches 
 some params.
  to get your reflection occlusion just check the box 
  and then reduce the angle to about 15-30 degree,
you can also blend the reflection vector with the
normal vector.. also in the rendertree you can 
plug any vector as vector base.
  if you need an environment reflection occlusion
  check also environment of course and maybe play
  a bit with the dynamic ranges and color correction
  to get the efx you are looking for. when in 

environment mode you can check the
box to allow the shader to put in the alpha channel
the ‘pure’ occlusion and in the rgb the env occlusion.
supported also bent normals and finalgathering
occlusion.I will add transparency maybe when time.



thank you francescaluce very much for this!

Seems to be very optimized for convinient workflow. I guess with transparency this shader would be hammer for all the occlusion needs.
thx again for saving my day!


francescaluc, if I may ask one question. What does the fg.view option under final gather tab do? Is it for view dependant? Having it enabled brings outstanding quality but render times are really killer compared to if that option is off. From distance the difference is also not so noticeable. How should one use it and in what situations? Thx alot!


What would be so cool with the occlusion is the possibility to ignore some of the objects in the scene.

I immagine 3 possible options :

  • a Defaut mode that consider all objects or
  • a List of object to exclude or
  • A list of object to include


But you can do that already, with partitions and groups. Just have different partitions with different settings and then it is just a matter of dragging and dropping from one preset to another…


Of corse it’s a work around but that’s exactelly the one I want to avoid, when you have already too much passes it’s time to try to stop to add them … I don’t want to descativate secondary ray as well (of objects to be ignored by the occlusion).



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