LC #42 Pipers Alley

View Full Version : Maya 6.01 and Dirtmap?

08-26-2004, 08:21 AM
So far all I've gotten are crashes with dritmap and Maya 6.01, anyone experiencing this? I spoke with several others who have the same problem. Looks like another patch full of fun...

08-26-2004, 08:32 AM
rendering fine for me Bill, havent used it a great deal since the update, but it certainly hasnt caused any probs with dirtmap renders.


08-26-2004, 05:17 PM
Ok, I just have to step in here real quick and ask what the Dirtmap shader actually does?

What does it render? A grime layer or something?

08-26-2004, 06:06 PM
dirtmap, great shader, its a kind of ambiant occlusion shader, it emits rays from the surface to find out how close that point on the surface is to anouther surface. So cracks and things will get rendered with a different colour, good for doing grime because you can darken all those detail bits that wouldn't usually get cleaned.

as for the 6.0.1 problem, i am assuming you have added the node id to the shader if you have been using it in 5, in 6 its needs the numbers.

if you have just upgraded from 6 to 6.0.1 i cant help

08-26-2004, 06:12 PM
I reinstalled the patch earlier this morning and now it's working fine. Not sure what the problem was, odd quirkyness. We have been using it in 6 just fine for a while now so not sure what the problem was, but it's working again.

Daniel Whitton
08-27-2004, 05:22 AM
Here's a stupid question, If I want te reveal those cracks( actually tire treads of a car I'm rendering) How can I set the dirtmap up to work with FG and HDRI, Its only supposed to work with Raytraccing right no lights needed. If I connect it to the ambient slot of any shader I get a nuclear render, Also if I render it with an MR_AREAlight I get the wierd Black corrput looking circles.

I'm guessing I need to render that as a completely seperate scene with only the dirtmap, then comp it?

How would I do that? Just one shader for the whole scene, then batch bake and bring it back in to my main scene and use as an irradiance color or diffuse texture to help light my scene. AM a I just overly confusing my self here or is it more simple.

Sorry for posting this question here, I was actually looking on the mental images mailing list when I saw that someone had the same problem as you and it was fixed with the mi patches.


08-27-2004, 06:36 AM
What I do is pipe it through a surface shader, run a pass as that. Then run a pass normally with my textures/shaders/lights etc. Bring both passes into Shake, iMult them together and adjust how much dirt shows up with the iMult percentage.

If you want the dirt to respect your physical lights, then pipe the out color of the dirtmap into the in of an RGB->HSV node. Then pipe the out.V value only to the diffuse of your base shader with your color maps or whatever on them. I don't ever do it that way because there's not really a good amount of control for the dirt without having to re-render over and over.

Daniel Whitton
08-28-2004, 07:02 AM
Thanks Bill for your reply. It makes sense to me now. I don't have Shake, but I have photoshop and AE, does it still work with the multiply, I'll check to see. Thanks alot.


08-28-2004, 07:15 AM
It should work the same way. The iMult node is just Image A multiplied by Image B, so anything with a value of 1 (say an rgb value of 235 from Image A times the value of 1, white, of Image B) will stay and you are just left with the dirt areas that are not a value of 1. The photoshop and AE math functions should be the same, although don't quote me on that.

08-28-2004, 04:11 PM
when i cant be bothered to render a spererate pass i stick the dirtmap into a luminance node, then into the diffuse channel of my shaders. Quick and 'dirty' :thumbsup:

Daniel Whitton
08-28-2004, 07:56 PM
Thanks guys for your help, hope to post some pics, I just bought somke space. Appreciate it.


08-28-2004, 08:32 PM
damn.... dirtmap and maya 6.0.1 don't work

I tried to use as usual for me... i put it in ambient color of maya shader.
The resul it's as a non-dirtmap image

I tried to put i in material shader of shading group section of maya shader but anithign...same image.


if it's a dirtmap problem..i hope animus correct this...because dirtmap it's a great shader...

Daniel Whitton
08-28-2004, 09:04 PM
From what I understand after installing the 6.0.1 patch you need to reinstall the dirtmap patch.

08-28-2004, 09:19 PM
Try doing it this way:

basically a luminance node between your dirtmap node and your diffuse node


08-28-2004, 11:10 PM
Any ideas why diffusion isn't working in 6.0.1?

08-29-2004, 02:07 AM
Check to see whether your Maya.rayrc file was replaced by the default one when you installed the 6.0.1 upgrade, because it does that.

I've had one unusual crash with Dirtmap and 6.0.1, but after that everything seems to be ok.


08-29-2004, 03:47 AM
Check to see whether your Maya.rayrc file was replaced by the default one when you installed the 6.0.1 upgrade, because it does that.

I've had one unusual crash with Dirtmap and 6.0.1, but after that everything seems to be ok.


I have not even checked DirtMap yet. I was in the middle of building something using Diffusion, and now it just keeps crapping out on me.
But as far as what you said the Maya.rayrc is definitely not it. I've been compiling shaders up the wazoo for the past few days, and I've been in, and out of the Maya.rayrc 100 times.
It's been checked, and re-checked.
Thanks for offering the help though.

08-29-2004, 03:52 AM
onlooker, what OS are you using, I had a permissions problem a while ago, but a chmod -R 777 om /usr/aw/mental ray folder fixed that, just a thought though anyway.


08-29-2004, 06:28 AM
Heres a trick to get a global dirtmap effect without having to apply it to every object in the scene. I found this in the XSIbase forum and have adapted it to Maya.
It also makes use of some of my shaders. ;)

Connect Dirtmap -> JS_Color_to_Vector -> JS_MultiplyDivide
and a lens shader (JS_fisheye will do) -> JS_Color_to_Vector -> JS_MultiplyDivide (The same as above and set it to multiply)
Set the Distortion of the fisheye to 0 and uncheck mask.
(This will give you a lens shader that is just a passthrough shader without any effect.)

Connect the JS_MultiplyDivide to your camera as a MR lens shader and render away. :thumbsup:

P.S. The JS_Color_to_Vector isnt necessary but gets rid of some warnings in the output window.

08-29-2004, 06:55 AM
Hey cool, nice tip.

I guess that could work for lots of things!


08-29-2004, 07:34 PM
i must correct my previous post.

Now dirtmap works with maya 6.0.1

I can't understand what i made for this..but it's work..


09-13-2004, 07:34 AM
I just recently began using maya on OSX and am getting my environment togerther. I would love to get the dirtmap shader working but dont know how to approach compiling it. I do have som experience with unix coding so a technical answer would be great.


04-01-2005, 07:50 AM
forgive my ignorance but im a little lost here..
how do i connect all those shader? i mean what should be connected to what?:shrug:
care to post the shader network for this dirtmap to camera trick


04-01-2005, 03:36 PM
Try doing it this way:

basically a luminance node between your dirtmap node and your diffuse node


Maybe Im being sneaky, but save another node and just connect the out R or G or B of dirtmap to the input you need if you need a scalar output... Then set dirtmap to white with black dirt.

I have an OSx compile of dirtmap/diffusion ill put on my page tonight.


04-01-2005, 03:59 PM
In terms of Motion Blur, How are you guys handling compositing your occlusion passes with your other plates. I've been wondering because I'm going to be rendering a project with the standard maya renderer with 2d motion blur. Then overlay the occlusion pass. Do you just use the "transformation" blur in the mental ray globals? Would the plates match up? Just wondering if the two different renderers would create a weird conflict.


dynamic duotone
04-01-2005, 04:04 PM
Tom_c did you have any luck with Mix8Layer - I noticed that Francesca might have been able to help you, I was having the same problems. I sent you a PM...


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