How to use PTex in Maya 2013

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  04 April 2012
Originally Posted by cmptrArtist: How can I use ptex as a bump channel? Maya wants to convert the file to an alpha and the bump channel only has a single input. Should I run it through a rgb -> Luminescence node first?


mental images goes into detail about how this is done here: http://forum.mentalimages.com/showt...up-in-maya-2013


hth,
ron


Last edited by ronviers : 05 May 2012 at 10:44 PM.
 
  05 May 2012
still can't get ptex to work

I can get color, but vdm crashes, and I can't get the bump channels to connect at all.
 
  05 May 2012
Still get nothing.

Quote: Create/edit file maya.rayrc in the user Maya directory 2013/prefs/ (or 2013-x64/prefs/ or /Maya2013/mentalray/) and add the new registry setting below.

Example (Maya2013 64bit on Windows Vista/7):
Edit the file:
C:\Program Files\Autodesk\Maya2013-x64\prefs\maya.rayrc

add the following line:
registry "{_MI_REG_CCMESH_PTEX}" value "on" end registry


Using PTex textures in Maya:




  1. Create a regular polygon mesh
  2. Assign a mental ray subdivision approximation
  3. Assign any material shader
  4. Create and assign a new node to a texturable color slot using mib_ptex_lookup
  5. Write the full file path to the .ptx file (relative paths won't work)
  6. Render


Despite having done all that, I still get nothing when I render. I've used the default tree stump model in Mudbox at low rez level. Exported it as an OBJ with a .ptex file (bark texture) to go with it. Opened the OBJ in Maya and did steps 1 thru 6 and I get nothing. I've put the files on my desktop and copy pasted the full path of the ptex file into the mib_ptex_lookup node which is plugged into the color of an mia_material_x node. I don't get error messages, so it must be kinda working. I'm just not seeing anything when I render. Is there an extra node that needs to be placed between the ptex lookup and color? Thanks guys.
 
  05 May 2012
I had to change the \ to / in the file path names. also the rayrc file must be edited as indicated if you didnt do that
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  05 May 2012
i did all steps exactly, still the head renders "black", nothing shows up in render
i tried reexporting the ptex textures but with no results, any ideas ?!
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FOLIO



 
  05 May 2012
Still get nothing.

Quote: I had to change the \ to / in the file path names. also the rayrc file must be edited as indicated if you didnt do that


Tried the forward slash as well. I downloaded the bunny example just to see if my PTEX file might be done wrong. I think there might be other technical subtleties that haven't been mentioned yet. I'm simply trying to plug the mib_ptex_lookup into the color slot for the moment and get that to work before I even think about vector displacement or other more advanced stuff. Baby steps.

I've looked at the scarce info on MentalRay and PTex and found this http://forum.mentalimages.com/showt...-rayrc-location and this one from another thread http://forum.mentalimages.com/showt...up-in-maya-2013 but again, that didn't fix the problem.

I believe that this new way of texturing will gain great advances eventually and will be simplified as time goes by. For now, I'll make way for the TDs to solve these issues that are way over my head.
 
  05 May 2012
Registry line

When modifying the .rayrc file, where does the registry "{_MI_REG_CCMESH_PTEX}" value "on" end registry line go? Maybe I haven't pasted it in the right area. Every line in the code has the # symbol in front of them. Does that need to be added or pasted as is? Sorry for the lack of programming vernacular. I'm just trying to get my Mari/Mudbox texture to be rendered in Maya 2013. Thanks.
 
  05 May 2012
I have been using a mib_color_intesity node to pass the mib_ptex_lookup into the mental ray displacement shader of a MIA X material. So far it works fine for regular displacement, but when I use Vector Displacement ptex files from Mudbox, I get lots of seams in my render(Maya 2013, mental ray).

Any ideas on how to get rid of these seams?
 
  05 May 2012
For the non techies. (like myself)

In the Maya.rayrc file. Remove the # in front of the added registry line for ptex or it won't activate it.
 
  05 May 2012
Glad you got it sorted, the # denotes its non executable text for annotating script
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  05 May 2012
Vector Displacement.

Has anybody been able to get a ptex vector displacement map to work in Maya? Regular displacement works like a charm, but haven't been able figure out the right node for MR in Maya. Tried the mib_data_get_shader_vector node but that doesn't change anything. I guess there needs be a custom node created for that?
 
  05 May 2012
Originally Posted by Rawburnt: Has anybody been able to get a ptex vector displacement map to work in Maya? Regular displacement works like a charm, but haven't been able figure out the right node for MR in Maya. Tried the mib_data_get_shader_vector node but that doesn't change anything. I guess there needs be a custom node created for that?


Can you post a mesh and ptex vector displacement map? I think I know how this could be done but I need some example files to work with.
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  05 May 2012
Got it.

Been able to get vector displacement with this guy's http://joomla.renderwiki.com/joomla...=331&Itemid=229 shader. Plug the mib_ptex_lookup into the "normal" slot in his vectorDisplace node and then into the shadergroup displacement shader. No seams or artifacts. Ptex rules!

Make sure that when you do a VDM extraction in Mudbox, that you use "object" in the Vector Displacement Map Options.
 
  05 May 2012
Originally Posted by Rawburnt: Been able to get vector displacement with this guy's http://joomla.renderwiki.com/joomla...=331&Itemid=229 shader. Plug the mib_ptex_lookup into the "normal" slot in his vectorDisplace node and then into the shadergroup displacement shader. No seams or artifacts. Ptex rules!

Make sure that when you do a VDM extraction in Mudbox, that you use "object" in the Vector Displacement Map Options.


Would be nice to get tangent space working though. Can someone post a obj and ptex tangent space vdm to test out?
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MentalCore - Shading and rendering pipeline for Maya/Mentalray
 
  05 May 2012
Originally Posted by mercuito: Would be nice to get tangent space working though. Can someone post a obj and ptex tangent space vdm to test out?


Did anyone get this to you? If not I can make a test object/vdm for you. Would be great to get it working.

-NB
 
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