WHY? a wavy displacement problem

[slorpthegillman]

Hi all,

I’ll try and be as detailed as I can, as I am looking to understand what is going on here and why my results are so different.

My model was created entirely in Maya 2009 (MAC) and UVd there as well. It was imported directly into Zbrush 3.2 (MAC) and sculpted. There was no back and forth exporting, and GoZ has not been used (yet) for this model. I am aware of the issues of how zbrush will break apart UVs (and how it can be fixed: http://www.andrewklein.net/ai/zbrushdemo/fixuvs.jpg). My UV map(s) look like this:
http://andrewklein.net/images/webready/floundress05_uvs.jpg
I am using 2 square textures, not 1 rectangular one, just to be clear. I simply displayed them side by side. My UV shells are welded properly.

The issue that I am having is entirely internal to Zbrush.

My base mesh is 2,587 polys. It is 41,057 at level 3. At 10,477,000 at level 7

If I go to level 1 and create my displacement map
Adaptive, DPSubpix4, 32bit
when it applies to my model (which happens immediately after creation) my straightly sculpted stitching lines become wavy and distorted.

If I go to level 3 and create my displacement map
Adaptive, DPSubpix4, 32bit
it looks great.

WHY? I am having a hard time understanding why it looks better if I create it the second way. I have created an image that helps explain it as well:

I am open to all thoughts. My guess is that being “closer” in form to the eventual top level, there is less room for error. That perhaps 2,587 polys is too low not to expect distortion as it translates to the UV map.

If my guess is correct, what would be the “best practice” for these sorts of scenarios? Should those best practices be applied when creating a normal map as well?

Follow up questions:

-Would reproject higher subdiv help here?

-When I make the map at level 3 (I have done a delete lower so that it is the new level 1). When I reconstruct the subdiv back down to level 1, the map still looks great. This confuses me even more. Thoughts?

OK INTERNET, DONT LET ME DOWN HERE.

-confused knowledge seeker.

[aurick]

At the lowest level, simply turn off Transform>Quick and set Tool>Display Properties>DSmooth to 1. You might also increase the slider next to it. This will smooth the model so that your displacement map can render without seeing the polygons.

[slorpthegillman]

Aurick, thank you for your quick response.

However, I’m not sure this was what I was looking for, as I think my first post must not have been clear enough. This solution does create less of a polygon-ization at level 1, and is a pretty neat function that I was previously unaware of in Zbrush. So thank you very much for that. Here’s what I did this time around though:

I applied the settings you mentioned, then created my displacement map while at level 1 of the model, with all the same settings as in my original post. When the map created and applied to the model, it looked like this:

-I would like to make it at level 1, but straight lines do not get made as straight lines.

(How) Can I do this?

----and-----

Why does this happen from a technical standpoint?

Thank you for all of your help. In the end, the answer may be: just make it at level 3, and I’m ok with that. I just want to know why, and have someone tell me “officially” that this is the best practice.

-andrew

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