Displacement Detail in Mental Ray a No-Go

[narntson]

Hi, I have studied and followed Scott Spencer’s Maya Displacement Guide, looked up other threads, but cannot solve my detail problems in Mental Ray from my ZB3 sculpture! I’m using the MD3 script and will then later do bump mapping for fine details like skin pores and wrinkles.

The setup should be solid but let me reiterate:
I create a displacement map using MD3 with R32 Code DE-LBEK-EAEAEA-R32. Starting from the startup head tool, I did my sculpting to subdiv Level 6 at over 3.6 million polys and then defined my settings: I hit AUVTiles; thus my UV’s should be fine. Didn’t touch anything under Tool/Displacement because I understand the MD3 settings override them. (Adaptive unchecked, DPsubpix 0, DPRes 1024) Under MD3 I lower mapsize adjust to 0, Maxmapsize to 4096, DPSubPix to 2, and Border at 8. I go all the way back down to subdiv Level 1 and hit Create All.

I got bad results so I resculpted my mesh to accentuate the highs and lows in my relief, thinking this will bring out the details. No changes were imminent in the second test.

Here are my two Zbrush pics (original and more pronounced) along with my last result in the Mental Ray render.

I even tried adjusting the contrast of the TIF in Photoshop to emphasize the variance of black and white, yet it won’t allow my to adjust as it is 32-bit?

Also, I’ve used convertfile.bat to convert my TIF to a .MAP file.

I’m using Maya 8.5 with the MR approximation editor subdivisions–Spatial; Min. 4, Max 5, Length .1 (Feature displacement OFF). My Alpha gain is 2.2 and offset is -1.1 and MR quality set to production…

My render globals setting for mental ray Translation doesn’t offer any export verbosity for progress messages either.
Can anyone offer any suggestions? Is the subdivision approximation smoothing out my model too much? I also didn’t use any cage settings either. Thanks for your time.

Attachments

[narntson]

I tried again with more definition from Zbrush…

Here’s the output in Mental Ray, I only get smooth approximation and no detail.
Should I see variances on the TIF or MAP file with the naked eye? It is only solid grey when I inspect it in Photoshop.

[narntson]

Okay great–I found joie’s post my subpixel 2 setting will only work with alpha gain 22. But I thought upping subpix to 2 is better than 0, yet everyone on here is using alpha gain 2.2, why create the map with only 0 subpix then? Also notice this banding problem I’m having, what gives? (I’m on 8.5 Xp x64) This was in Production mode Min2 Max3 AntiAlias Sample Mode ???

[TrackZ]

Have you ever thought of using mrProxy files instead of displacement maps?

[narntson]

Track-Z, I should look into mrProxy’s in the future. My goal is to create photo-real maps to drive my displacements on my blendshapes.

How come I can’t get this pipeline down?? After thinking my “banding issue” was because of my uvs, it still does this…

Thought a solution was to reconstruct my uvs on my basemesh from Maya using Pelting Tools?? However my uvs were overlapping so I manually corrected them, then I exported the new UV mesh back into Zbrush.
(Zbrush uv>check ensured that this issue was okay)

I export my new Displacement map, and export/import the basemesh back to maya on my target model and set up my hypershade, alas my displaced .tif comes out red, (always thought it was gray/or is that for 16 bit on MD2) even after changing it to a .map. file. I believe this is legit for a 32-bit map, right? The R-32 in the export code means it has to read it in the red channel, am I right? Maybe the Pelting Tool somehow adjusted the scale for my UVs, because I have some bogus UV tweak at the bottom of my base mesh as you can see from the screenshot.
Any suggestions on what approach I need to do??

[jbuck]

Your UVs look fine and the seam issue in the previous shot sounds a lot like the dreaded and oh so stupid CCmesh issue with Subdiv Approx. and Maya 2008 but you say you’re using 8.5?

In DE3 try leaving DpSubpix at zero and setting scale to Auto. Depending on your mesh I’ve found this to provide a more accurate disp. map that doesn’t require one to crank up the alpha settings. And you should definitely see SOMETHING in your disp. map even at 32-bits.

What’s the bump2D node for in your shader network?

[narntson]

Thanks for the tip Josh. I tried it and still get a jumbled mess. CCmesh I just looked into–must totally be a 2008 deal, because yes I’m running 8.5. The bump2D node–I read about that once; supposed to be among the displacement network “under the hood”. Correct me if I’m wrong! I just hit show all connections from my material node and it surfaced.
Perhaps my UVs are a wreck in Zbrush then. If I can pinpoint this then all I have to do, is map it again and stay away from the pelting Tool.

In Zbrush, this is after hitting UV>Txr. Shouldn’t it be nicer looking?

[jbuck]

Your UV’s still might be okay. What it look like when you press Texture -> Uv Check?

I haven’t done much displacement mapping in 8.5 and CCmesh approximation aside it’s easier to set up disp mapping in 2008.

[narntson]

It goes completely grey. No Red = means Go straight ahead!

[narntson]

I found the solution–
Within Maya, I definitely had to make sure my pelting or projection mapping had no overlapping uvs. But the real hidden problem was in my MD3 Export settings; I had the code right, but what caused my displacements to appear red in the hypershade as opposed to solid gray, was that I had an extra “R32” button activated making two R32 buttons activated–sending two codes at the same time! I guess it crossed wires and caused my .tif map icon to look red?! instead of the correct solid gray color. So make sure only one button status is on and the other is off!! Here is the resulting image that I was yearning for in MR subd approx. editor-

Now for the fine pores, should I do bump or normal maps-anyone with an opinion of which is more advantageous, I’d love to hear…