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rebuild Zmeshes in Maya 6

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#1

demoBody.jpg
demoBody.jpg1295×768 98.9 KB
I have been working on solutions to obtaining Normal Maps with Zbrushed meshes out side of Zbrush, there are some problems with usning Zbrush in a practical pipeline for generating Normal Maps, the problem being you cant compare 2 meshes for a normal Map it has to be the same mesh just smoothed out. So I have been bringing my high res Zbrush meshes back into Maya, making them LIVE and rebuilding very low res characters. This is an interesting way to work because all you are doing is laying down surface topology and watching how the edge flows are lined up with the detail in the high res model. the original mesh I brought into Zbrush and subdivided was an older mesh and I was only using it as a pallete to sculpt on, now this method obviously makes more since if you started your model in Zbrush with Z spheres and never had the original low res mesh. But the main point of this experiment was that when you were laying down the low res mesh detail all you had to think about was edge flow cause the points were snapping to the live mesh that had all the detail and volume already there for you, and when you are done with your new mesh you can use whatever tool you want to createte the normal or displacement map based on the two meshes.

-problems where Maya doesnt handle really high res meshes very well, I ended up bringing in a version of the guy that was 500,000 polys and deleting half of him, this was plenty to just have the form represented for the low res rebuild, and could have been even less.

this might seem like an odd thing to do but I found it rather interesting and though I would share :slight_smile:

I used Maya 6 to generate the normal map for this test and to also display it with the new High quality render tab in the openGL display window via a normal Map shader from the net-

#2

Same process with Hand testdemoHand.jpg

#3

Good modeling on the hands,Thanks for shareing.

IS Maya LIVE similar to Silo’s Topology Tool…?

Thanks!

#4

Nah, it’s more like a skinWrap deformer - projection modeling that is.

I’m interested in that normal shader you’re using, Ktayler - Is that the drone.org one? For me, normal Maps in Maya have always been a major problem…

#5

Hi Ktaylor,
What a pleasure it is to model in zbrush no?:slight_smile:
Welldone male model.

As for the method , it indeed is much more efficent interms of at least in quality to re-topologise the mesh as an after process. 2 years ago I tried this same workflow in maya. There are two other application that do this work very well. Cyslice from Headus and Paraform . They can handle millions of polygons with ease and they have streamlined tool sets to do exactly this type of work. ( relatively streamlined )
As both are very expensive ( not known or readily accesible) and this method of work is not yet popular , despite its advantages , I’m in the process of creating a video tutorial showcasing paraforms workflow with zbrush and presenting a method and tools , normativley speaking, to carry it out. I endevour , as I’m not a programmer , that developers or talented programmers, can create or implement such a toolset with the awareness and advantages in view.

In alot of cases this won’t be nessesary. A model could be created in maya exported and brushed in zb. The main advantage is during the design process. Using zbrush your is so easy to add and remove new features, making the design process very natural and unhindered by constantly have to pay attention to topology. The ability to mix and match topolgies between characters is also something cool I will show.

Btw - how did you go about combining the hand and the body , normal maps, were you able to do it matching the normals without any seams?

Thanks for sharing your experiments.

Kircho

#6

It seems to me that the greatest disadvantage to generating normal maps in Zbrush is that your hires model has to be a derivative of a lores. Other utilities out there, like ATI’s Normal Mapper don’t have this limitation as you can generate maps from arbitrary meshes. The program projects “searcher rays” from the lores, UV-mapped surface normals and whatever they hit is accounted for in the normal map. There doesn’t need to be a one-to-one correspondence between the two, which gives the artist great freedom and has proven to be less prone to artifacts resulting from skin folds and overlaps in the detail sculpt.

Leveraging the freedom of this workflow, one could potentially sculpt from finely-divided amorphous “lumps” until arriving at an interesting shape without any concern for topology! (yes, even utilizing multiple meshes with Multi Markers). Then, as you mentioned in your post, export some version of the polymesh subD chain to use as a template upon which to stitch more appropriate edge flows for animation in Maya by making the mesh “live”.

The only catch is that ZBrush doesn’t export the normals in its .obj format which is necessary for Normal Mapper to perform its calculations, so one is forced to import and re-export in Maya to assign this data. But try doing that with a model that weighs in 4million polys or more!

And this is where ZBrush really shines - one can push around millions of polys like they was buttah - in fact, “I can’t believe it’s not buttah!” - but unfortunately for us Maya users, we can’t directly harness this power. What I want is to model to my heart’s content in Zbrush, then import a topologically appropriate mesh that morphologically resembles the hi-res but is a synthetic derivative, and generate my Normal Map from that!

(Pixolator, aurick, If you’re taking suggestions for the next release of ZBrush, this is definitely high on my wish list!) :wink:

#7

hi kublakai,
The solution is the reconstruct tool. Pixologic has created this program with a great amount of foresight.

Model in zb upto to the stage when you just about to add your skin details, such as wrinkles and pores.
Take your zb mesh out and draw the correct topology in the form of an interconnecting grid ( See Below)
By virtue of the process , which I suggest should become commonplace, the generated mesh can be exported at an extremely high resolution , close to zbrushes infact, and the level of detail recontructed down to the very base back in zbrush. So as to complete the circle.

From this point onwards you can add those fine details and generate your disp and norm maps with the new topology.The most beautifull part is that you still maintain all your contruction levels.
Re-top.jpg
Just to place a tengible solution on the problem:)
Time to generate the new topology is 1 hour in this case. However , as I’m very much out of practice , it can be achieved in a much shorter time. Even more so because you can recycle the old topology.

I can’t see this happening in zbrush, as effectivley that is. I’m sure they could update the import mesh alogorithem to allow for different topologies , but you have no control over the placement of the loops.

I think the best thing Pixologic can do is make a plugin for zb that acts like a birdge between the topologising program and itself.

There is a very interesting plugin for XSI that converts displacment maps to subdivision surfaces. For models , not so complex, the plugin could tesselate the Subd suface levels based on the disp map. SO you don’t require normal or disp maps at all at render time. HMM Somtimes I can really see the value of being a programmer:)…when working in zbrush I don’t lol:)

Well hopefully the last bit of prattle from me until my tut:)

Kircho

#8

Hi Kircho. This particular topology draw example was done on wich software?

#9

It’s been awhile, but it looks like Paraform. If so Rob, Z and myself, were doing this back in 2000. But it was very expensive… and not our money.

#10

Thanks sirquadalot. :wink:

#11

Hey that is very interesting indeed Kircho, yeah I totally agree with you that once your in Zbrush there is no telling what you may do to the model that would require you to have to rework your original cage mesh, It would be great if Zbrush would incorporate this kind of topology brush or something. But this tool looks very promising, be sure and keep us posted on its development.

In this case the hand model is its own seperate thing and isnt in anyway incorporated into the main body model. The hands on the body model were pretty sloppy and didnt allow for the proper sculpting in Zbrush so I just made a standalone hand, I have a foot that was constructed on its own as well and I will Frankenstien them all together at some point:)

-Mahler
Im not sure where the shader came from as I got if from someone in the studio, but Ill track it down and get back to you.

#12

Wow, Kircho - thanks for the feedback. I need this tool! What is it called, and more importantly, can I afford it? I know Headus makes excellent re-surfacing tools, but unfortunately beyond the reach of someone working independently outside of a commercial production…

From the images you posted, it would seem that this tool operates on the principal of spline patches - much like Animation Master, only here they are bound to the underlying UV space of the model to be surfaced - very attractive indeed!

#13

Well Kircho, it is always nice to see the process of others. I work similarly, but I like to paint the info on in Zbrush to give a guide when I’m in Maya to make the base mesh. I have had some success with setting up a good Zsphere model, and getting the base shape then extracting the coloured mesh from the Frame button. The higher levels of subdivision give a pretty good base and means of reworking. Then I paint on the extra info I want, then go to Maya and use Live surface.

I’ve noticed that at higher resolutions in Zbrush you get what looks like splines when moving your mesh - I assume a derivative of what I already grab, but the info should be acquireable and thus transferable, or transformed into a better base mesh or guide for a base mesh. This would be similar to some NURBS stuff I’ve utilized in the past. I’m still working on it, and will post any successes.

Topology brushes sure do offer some possibilities.

:smiley:

#14

“There is a very interesting plugin for XSI that converts displacment maps to subdivision surfaces. For models , not so complex, the plugin could tesselate the Subd suface levels based on the disp map. SO you don’t require normal or disp maps at all at render time. HMM Somtimes I can really see the value of being a programmer:)…when working in zbrush I don’t lol:)”

And where does one find this plugin? As a XSI/Zbrush user it sounds very interesting to say the least!

Greg Punchatz

#15

Here you go punchatz:) I found a new one while looking for the plugin I refered to in my post.
http://www.xsibase.com/tools/plugins.php?detail=507
http://www.xsibase.com/tools/plugins.php?detail=444

–

Yep its Paraform. Hopefully I can show you all the wonderfull things that are possible with such a software and my suggestions for improvement.

all the best

Kircho

#16

-Mahler
Im not sure where the shader came from as I got if from someone in the studio, but Ill track it down and get back to you.

Man, that’d be great!