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stascrash
07-05-2011, 05:34 PM
hey guys, I have a very weird problem here. I am working in Maya 2011 (same issue is in 2012).
Working on a model that needs to have Displacement map attached. I am using MIA_MATERIAL_X shader, currently setup as a default mat with just a Displacement plugged in.
http://content.screencast.com/users/stascrash/folders/Jing/media/970e09ba-eb72-4671-bbc7-48a71d10d1e3/2011-07-05_1126.png
i am using a default method of attaching a displacement node to the shader:
http://content.screencast.com/users/stascrash/folders/Jing/media/1b5057e9-c5d7-4634-acd7-218d596ff3ac/2011-07-05_1127.png
I got this setup to render pretty well and i am happy with results. However on the next maya restart this scene simply won't render no matter what i do. I checked all of my connections and nodes, and file locations, everything works and looks ok. Maya does not throw any errors or renders, it just renders the image without the displacement. I tried rebuilding the shader the same way, as well as re importing shader only to fresh scene and backwards, nothings seems to work, rebooting pc, and even going to maya 2012... i am clue less as in what could go wrong... If you guys have any ideas, please share them :)
few more screens of the settings i have:
For the Mental Ray approximation editor for the "Displacement" i have:
http://content.screencast.com/users/stascrash/folders/Jing/media/caa7ecf6-af7d-441c-9f66-5264622647ab/2011-07-05_1131.png
and i have also disabled the feature displacement for the Object's attributes:
http://content.screencast.com/users/stascrash/folders/Jing/media/5a4dea9f-ac54-48e3-8d29-3d6660019c42/2011-07-05_1132.png
If i keep this option on, then maya just crashes, or sits at "rendering"....
Thanks in advance. i will try any suggestion at the moment now...
:banghead:

Eshta
07-05-2011, 06:17 PM
lower your approximation settings and see if it will go

stascrash
07-05-2011, 06:30 PM
Thanks, i just tried a number of combinations, and pretty much i dont see any changes, except the render time.. so it calculates something extra, but not visually.
This right here is the mesh with UVs :
http://content.screencast.com/users/stascrash/folders/Jing/media/0b9488d4-8e06-4ae6-b19c-8b4e7740b45b/2011-07-05_1222.png , as you can see it is fairly simple.
This is a quick z-brush:
http://content.screencast.com/users/stascrash/folders/Jing/media/ec0c9855-1f19-4f7e-b833-11f4c6ccb7b8/2011-07-05_1222.png
at the end, i can export this displace from zbrush and slightly tweak it in PS to get :
http://content.screencast.com/users/stascrash/folders/Jing/media/cd6c522e-8de1-4e90-a1df-d8c8c4001cd7/2011-07-05_1223.png
I play with number of settings for displace FILE under color balance, to figure out the proper values for the apha, however i end with very plane results 90% of the time, currently settings i have:
http://content.screencast.com/users/stascrash/folders/Jing/media/dbd7cfb6-624a-4846-b7c9-5a69b2242527/2011-07-05_1223.png
and the render i get looks like that :
http://content.screencast.com/users/stascrash/folders/Jing/media/d464a11d-2aec-480e-bc8e-7a6a7c93c521/2011-07-05_1225.png
now, i normally can get away with displacements when i work with landscape, but this time around it is a slightly different project direction... To get the fine details i am using normal maps, and those work just fine with this mia_material_x by means of misss_set_normal2... and advice on displacements?

nookie
07-05-2011, 06:34 PM
I think you should try to export your map as a 32bit image and then set the "Alpha Offset" as - 1/2 "Alpha Gain" (so if Alpha Gain is 1, Alpha Offset is -0,5). (you are setting middle gray not to do anything this way)
Check that "Alpha is luminance" is checked too...

stascrash
07-05-2011, 06:46 PM
Yeah, i tried many different settings for alpha gain there, nothing really was helping,
now, for the 32-bit, i am exporting them from zbrush, as tiffs, but having hard time saving them int TGAs or just simply plugin those for the texture, i get warnings that this is an unsupported file, and that it must be 8 or 16 bit... could briefly explain the work flow?

stascrash
07-05-2011, 06:55 PM
Well, it looks like it works.
I could not get the TIFF image to work, so i made an HDR and used that for file texture.
played a bit more with colorgain/offsett and aproximation.
here is what i have :
http://content.screencast.com/users/stascrash/folders/Jing/media/be3e511d-1b41-4036-912f-c5652e94f9c2/2011-07-05_1252.png
i am happy with this quick test, and now can move on...
the mystery of it suddenly turning of after maya restart is still there, but i am glad that it is fixed.
Thank you guys. :)0)

nookie
07-05-2011, 06:59 PM
uff, i did that REALLY long time ago and I have no zBrush nor Maya nor (softimage T_T).

Anyway, 32bit is not supported in tga (i mean 32bit per channel) so you should use tiff or exr or whatever you can export from zBrush that supports HDR values.
Did you check the alpha is luminance checkbox? if you donīt check that maya is going to use the alpha of the image to displace it...

stascrash
07-05-2011, 07:01 PM
Yeah, i ticked it on, and i used HDR as an image format, worked really nice.
thanks for pointing out the 32bit thing, i dont remember reading about it anywhere... ;)

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