Hello!
This is my last image, rendered with mentalray using the dirtmap shader.C&C are welcome 
http://img17.exs.cx/img17/8714/interna21ty.jpg
Ha sanyone compared what the speed/ performance difference is between dirtmap and the mentalrayteams own occlusion texture.
Wich one is faster? any benchmarks?
Well, i really dont know, this image was rendered using FG/GI + the dirtmap shader.It took me 3 hours to render at 1280x1024, but im using a damn slow computer, an Athlon XP 1,2ghz with 512mb ram, cause my other computer went dead..lol
Well you hae a good scene to make the comparasion in. Try and substitute it woth the simple occlusion to test and se?! (wouldnt you wnat to know if you do pictures that render that long!)
You can obtain it form alias, its in the sub surface package. Some report that it isnt there but they all also report that they cant find the SHADER, and they cant because its a TEXTURE.
OK, this means war!!
or at least a screen capture:
http://homepage.mac.com/tim\_turner/.Public...g\_occlusion.jpg
Notice the misss_lambert_gamma, which proves I acutally installed it....and the "Environments" tab below it, which proves that it is not simply hidden by the interface somehow....
Mybe its not just available to macosX for some reason? Ive said this before. This would be a plausible reason.
Have you perhaps tried reloading the pack.
From my point of view mac users are a bit sadly and UNJUSTLY classed as 2nd class citizens as far as 3d progs go, just bacuse they are a small slice of smalll slice. (yes 20-30% of new sales used to be mack that means that the mac slice is a ever dimishing in % size)
Anyway you can get the source form mental images ftp site and compile them yourslef?!?
as mr.gif
never bothered to save the icons as i dont use the ui like this most of the time so i dont se the icons in anycase.
and just so you know this is my registry art of my maya.rayrc
registry "{MRMAYA_START}"
link "{MAYABASE}/lib/subsurface.{DSO}"
link "{MAYABASE}/lib/base.{DSO}"
link "{MAYABASE}/lib/physics.{DSO}"
link "{MAYABASE}/lib/mayabase.{DSO}"
link "{MAYABASE}/lib/contour.{DSO}"
mi "{MAYABASE}/include/subsurface.mi"
mi "{MAYABASE}/include/mayabase.mi"
mi "{MAYABASE}/include/base.mi"
mi "{MAYABASE}/include/physics.mi"
mi "{MAYABASE}/include/contour.mi"
echo "mental ray for Maya - startup done"
end registry
and the specific parts of subsurface.mi I would start by cheking wether or not this is there! if it is there then its something wierd indeed. if not you could try to paste it there and se if it works (back up the old one tough)
#
# Simple ambient occlusion shader
#
declare shader
color "misss_simple_occlusion" (
integer "samples" default 16,
color "bright" default 1 1 1 1,
color "dark" default 0 0 0 0,
scalar "spread" default 0.8,
scalar "max_distance" default 0,
boolean "reflective" default off,
integer "output_mode" default 0,
boolean "occlusion_in_alpha" default off
)
version 2
#: nodeid 1091655
apply texture
end declare
Before i start this image, i did a test with the mi sss simple occlusion, i didnt liked the result, and i think its slow.Dirtmap its much more fast (sorry my english here..lol) and you dont need any light inside the scene, what i noticed with the mi sss simple occlusion is that it works only if you have a light in your scene. And for those who cant find the mi sss simple shader, check this at cgtalk, you can find it there.
http://www.cgtalk.com/showthread.php?t=170167
You dont need lights in the scene to use simpple occlusion either. Atleast i dont... Hmm i will test the dirtmap and se if i can get a deecent benchmark.
They need a bit tweaking as their default settings dieffer a wee bit. Also you may need to adjust the cryptic output mode gizmer wicjh isnt realy documented well.. but there was a site thet did taht too somewhere
but the truuth is taht they work a bit differnetly and from what i se id be supprised if the dirtmap realy is faster since it is realy much more computationaly intensive in what ive seen.
How Did you light up your scene?
I have projects about RV'interiors and have huge problems with lightning and the shaders.
I tried to use a dome with a surface shader for FG and two pointlights inside the interior with only emitting photons for GI.
but it doesn't work....since there are really smal windows.
can you help
Well, usually i use a pointlight converted into a MR area light with a square projection. All lights emitting photons.I put the lights in front of the windows, so it can generate some softshadows.Also i use FG, which is very important to help with the quality of GI.The dirtmap was used in a different pass, the occlusion pass, to help enhance the contact shadows. Most ppl think that the Dirtmap can be used in place of FG, which is a big mistake, cause they are completely different. You can find some information about this reading the Maya Docs. About the env. if you are using Maya 6 or above, i would suggest you to use the IBL instead of a sphere, cause you can have much more control over the Reflection/Refraction effect.
Hope it Helps
PS: Sorry about english......lol