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Displacement issues with maya 2010 and zbrush 3.5 r3

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#1

Hi there…I was wondering if anyonw could help me with displacement map issue on zbrush 3.5 r3

I know theres no multi-displacement plugin so i dropped model down to sdlvl1 created displacement map with (sdpixl = 2, adaptive on, 32bit on).
But when I just click create displacement map it creates a normal looking map image 1 below. When I click ‘create and export’ it creates image 2 below, which maya 2010 says it can’t recognise and also looks like there is no information there.
I also go through the approximation editors process for both the ‘displacement’ option and ‘subdivision’ option, and then maya usually freezes. So then I decrease the settings…but it inflates my model so I adjust the colour balance and I get a render with no-way near as much detail as I had in zbrush. (image 3)

I never had this much trouble with zbrush 3.1 and max, and I’ve searched for tutorials and forums and can’t seem t find why i’m getting these issues???

Does anoyone have a working method of displacement with maya 2009/2010 (mental ray) and zbrush 3.5 r3???

Thanks in advance

Arvind!

Attachments

image1.jpg

image2.jpg

image3.jpg

#2

Someone must have a working method…or advice for my issue…anyone!!!

Arvind!

#3

Hopefully this helps. Export as you were, but also check the ‘Flip V’ option in zbrush. Since Mental Ray won’t read 32 bit .tifs, you need to convert it to a .map. To do this open the command shell in windows, find where your .tif displacement map is. When you’re in that directory type imf_copy enternamehere.tif enternamehere.map

That will let Mental Ray read your map.

As for the approximations. It seems only the subdivision option works now; in my experience anyway. So I just use subdivision approximation only and it works fine. Just crank it up.

Also very important is to set the alpha offset to a negative value of half the alpha gain under the color balance of the file texture.

#4

I was just pointed to this thread by a private message. It looks like rissta hit the nail on the head. Is the render working now?

Adaptive mode is the only one that is working. You also need to flip the map and make sure it is 3 channels (RGB).

Cheers
Scott

#5

I’ll definetly give it a try and u ley u guys know, thx for the reply…lets hope ZBrush 4 has an easier method? :smiley:

Arvind!

#6

I’ve learned more. So for 32 bit maps out of zbrush you need to set the ‘Mid’ value to Zero. Since you set the Mid value to zero that means in Maya you don’t have to put the Alpha Offset value of the texture to half of the Alpha Gain. Also a great plus if you’re using Maya 2011 is the optimize auto conversion feature. Its found in Preferences>Settings>Rendering. It automatically changes your textures to .map files. It generates a new file and keeps the old one. The old texture will stay referenced in the file node but I like to path directly to the new .map file.

#7

I would think setting that value to 0 sets black as the midpoint which will give the map nowhere to displace in. There may be a bug in the map creation but you want your midpoint to remain 50% gray especially in 32bit maps

S

#8

I believe that if its a true 32bit float then zero is not the cut off, float can go below zero and above one. But that depends if zbrush exports as float. I’m going to double check if my displacement’s negative values are working but they’ve looked perfect as I remember.

#9

http://www.zbrushcentral.com/showthread.php?t=83524&page=1&pp=15

:smiley:

#10

Yeah the 32bit floating point format has negative values. Therefore 0 (black) = no displacement and negative values displace inwards.

Here’s a much better explanation than this though!:

http://forum.mentalimages.com/showthread.php?t=6258

Also scroll down for a reply from Slide London, who mention other settings and seem to be getting some good results on their website.

In Maya, I’ve just been disabling the file load, connecting up the displacement map, adding a spatial subdivision approximation, setting the distance value and hitting render. (Off the top of my head)

A bit further down it says don’t use ADAPTIVE though. Use DPSub pix in ZBrush. I know there was a lot of posts a while a go about the adaptive setting not working correctly.

Can anybody else confirm/explain this? I’ve been using Smooth UVs and DPsub pix and getting some pretty good results.

James

#11

Interesting link thanks! I don’t get how it is writing a negative value if no displacement is set to black and 100% displacement is set to white. It seems some values somewhere would contradict themselves. I may need to register on that MR site and ask the dev team. The fewer settings folks need to remember the better.

S

#12

I am no expert on this issue by any means, but strangely enough I get the best results when I use Adaptive and turn off Smooth UV.

When I use Smooth UV I always get a seam on the forehead of my character. Whether the UV seam is there or not there would be an indent right in the same place on any of my models.

After some fooling around I got it all to work fairly well without clicking the SmoothUV option.

It’s a funny thing getting this thing to work with MR.