Hi all
Is there anything similar to the Dirtmap shader available for Mental Ray that is available for Mantra or able to be built in Vops to be equivalent ?
(http://animus.brinkster.net/index.html) [animus.brinkster.net]
From what I hear the dirtmap shader is often used in industry.
J
Dirtmap
8519 8 4- JohnnyBGoode
- Member
- 55 posts
- Joined: July 2005
- Offline
- jason_iversen
- Member
- 12490 posts
- Joined: July 2005
- Offline
Not sure about the Dirtmap, but you can use (and modify) the Rust and Mold VOPs to some pretty good effect.
Jason Iversen, Technology Supervisor & FX Pipeline/R+D Lead @ Weta FX
also, http://www.odforce.net [www.odforce.net]
also, http://www.odforce.net [www.odforce.net]
- drew
- Member
- 118 posts
- Joined: July 2005
- Online
JohnnyBGoode
Hi all
Is there anything similar to the Dirtmap shader available for Mental Ray that is available for Mantra or able to be built in Vops to be equivalent ?
(http://animus.brinkster.net/index.html) [animus.brinkster.net]
From what I hear the dirtmap shader is often used in industry.
J
In the houdini world it's referred to as “ambient occlusion”. Check the video tutorials on vislab, I'm pretty sure there is a global illumination example that shows the use of ambient occlusion.
-Drew
- JColdrick
- Member
- 4140 posts
- Joined: July 2005
- Offline
I was going to say that can't be right, but yes, in some circles it does appear that's what they use this thing for - fake GI. That's really strange, and a seriously misleading name. I'm pretty sure “dirtmap” just means what it sounds like, though - a dirt map shader as Jason alluded to, apart from any tricks that it's used for.
Cheers,
J.C.
Cheers,
J.C.
John Coldrick
- drew
- Member
- 118 posts
- Joined: July 2005
- Online
JColdrick
I was going to say that can't be right, but yes, in some circles it does appear that's what they use this thing for - fake GI. That's really strange, and a seriously misleading name. I'm pretty sure “dirtmap” just means what it sounds like, though - a dirt map shader as Jason alluded to, apart from any tricks that it's used for.
Cheers,
J.C.
Misleading indeed, but the Dirtmap at http://animus.brinkster.net/index.html [animus.brinkster.net] is doing an occlusion calculation which you can see if you download the mental ray shader source. Its also referred to in this article http://www.evermotion.org/tutorials/rendering/xsi_dirtmap/. [evermotion.org] You can use the shader to get the look of things like polished objects where gunk gets stuck in crevices where in effect you have “cleaning occlusion”
-Drew
- JohnnyBGoode
- Member
- 55 posts
- Joined: July 2005
- Offline
Sorry, I should have been a bit clearer about the ‘dirtmap’ use.I have used ambient occlusion quite a bit with houdini, what interests me about dirtmap is that as far as i know it is used as a fake-occlusion and also a fake-GI.
It can gather ambient colour from an environment map for one pass and occlusion for another.
As far as i know this is all fake, and is used by industry quite a bit. So i assume it produces much faster results as a shader than using actual ambient occlusion?
Is there anything similar for Houdini?
It can gather ambient colour from an environment map for one pass and occlusion for another.
As far as i know this is all fake, and is used by industry quite a bit. So i assume it produces much faster results as a shader than using actual ambient occlusion?
Is there anything similar for Houdini?
- craiglhoffman
- Member
- 252 posts
- Joined: July 2005
- Offline
- JohnnyBGoode
- Member
- 55 posts
- Joined: July 2005
- Offline
oh cool
thanks for clarifying that for me. So as far as i should be concerned the Ambient Occ done through using a GI light shader in houdini will be no slower and no different a technique? (doesnt houdini let you use an environment map anyway?)
I always thought dirtmap as a cheat way to avoid actually using ambient occ - the Evermotion link that Drew supplied suggests this too.
I just assumed it because I thought it odd to be using a shader to generate ambient occlusion rather than a lighting technique like in Houdini?
Cheers
J
thanks for clarifying that for me. So as far as i should be concerned the Ambient Occ done through using a GI light shader in houdini will be no slower and no different a technique? (doesnt houdini let you use an environment map anyway?)
I always thought dirtmap as a cheat way to avoid actually using ambient occ - the Evermotion link that Drew supplied suggests this too.
I just assumed it because I thought it odd to be using a shader to generate ambient occlusion rather than a lighting technique like in Houdini?
Cheers
J
- Simon
- Member
- 2199 posts
- Joined: July 2005
- Online
You might want to look at this thread over at odforce
http://odforce.net/forum/index.php?showtopic=2876 [odforce.net]
It deals with the idea of fast ambient occlussion.
http://odforce.net/forum/index.php?showtopic=2876 [odforce.net]
It deals with the idea of fast ambient occlussion.
The trick is finding just the right hammer for every screw
-
- Quick Links