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Topological reconstruction workflow using displacement maps?

ZBrush Usage Questions
#1

Inside ZB, is it possible to use displacement maps to “port” sculptural detail between two models with identical silhouette but divergent topology?

My hope was to take a model created in zbrush, generate a displacement map, export one of the lower sDivs to another app (max, maya, etc…) to rework the topology and then import this new model into a fresh ZBrush document, subdivide it a bunch and then apply the displacement map created earlier to the new topology, and thus reconstruct ones original sculpt on top of this new topo framework?

I’ve seen a couple references to this technique on the forum, but despite my best efforts, I can’t seem to get this to work.

If anyone has had experience with this topic I’d love to hear how to get it to work. The posts coving this topic weren’t specific enough to aid me in my effort.

Cheers
Thanks

THIS DOESN'T WORK, but its as close as i can figure it... am i missing something.
  1. go to sDiv 1. and click Tool>Create DispMap
  2. go to sDiv 3. export as obj
  3. modify topology in an external app.
  4. import obj with new topo into a new ZB document.
  5. turn off Transform>Quick 3d Edit.
  6. turn on Tool>Displacement>Mode
  7. set Tool>Display Properties>DSmooth to 1.
  8. select displacement map created earlier and convert to a texture. Alpha>Make TX.
  9. set Tool>Displacement>Intensity to .1
  10. apply in Tool>Displacement>Apply DispMap
#2

Displacement maps are a form of texture. This means that for a map to be able to be applied to two models (or created by one model for viewing on another), those models must share identical UV mapping.

#3

Hey Aurick,

Thanks for taking the time to reply.

I figured as much about the UV issue. However even taking that into account, my tests, where i simply tried to “reconstruct” a hirez model from its lower sDivs (and thus the UVs should be the same), didn’t work (method: create a displacement map. deleting sDivs 3-6, reDividing sDiv 2 four time (i.e. back to an equivalent of the original sDiv 6), and then applying the earlier displacement map to the new sDiv6)

Also do the UVs have to be identical or just occupy the same texel space. For instance, in Maya when you add new edges using the ‘split poly tool’ the new edges are added to the objects UV space in a logical fashion so that if a texture is already applied to the effected area there is no noticeable visual anomalies. Thought the UVs are technically different (if for no other reason then there are now more faces UVed) they are for all practical purposes the same. I was therefore hoping that the displacement map would work in this situation. Is this accurate? If so, any guess why I’m not having any luck?

Thanks Again

#4

From what I understand, the UV’s must remain the same. I think the next version of ZB will allow us to do just what you want.

#5

There is a great tutorial on the Gnomon.com site for this exact probelm. But you have to purchase the video, Digital Sculpting: Human Anatomy to get it. It is in the lecture 11 part of the video. If you want me to explain how it works, call me at (858)229-0155.

#6

Sorry for the late reply,

Long Phan,

Thank you for your gracious offer. Fortunately I own the DVD (but I hadn’t bothered watching the last section yet). Stupid me. Thank you very much for the suggestion. A bit time consuming, but it worked great.

#7

Personally I think the whole xyShrinkwrap workflow is a pain. It doesn’t really save time, although it does free you up to create topology later. I’m really starting to loathe the whole conversion process.

I’m hoping Pixologic can think of a better way to do that type of workflow, mainly because it would be best to do it all in Zbrush anyway. I’m hoping we get to see some cool stuff at Siggy.