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View Full Version : Retopology vs. Normal Displacement Low-Poly Mesh??


meleseDESIGN
04-28-2010, 01:06 PM
What is the better process, Retopology a High-Poly mesh in zbrush or create a normal displacement map and put it on a low-poly (smoothed in Maya) mesh? Creating normal displacement maps in zBrush takes me only a few minutes, but retopology sometimes takes me hours.

Any thoughts?

;)

ezekiel66
04-28-2010, 02:13 PM
What is the better process, Retopology a High-Poly mesh in zbrush or create a normal displacement map and put it on a low-poly (smoothed in Maya) mesh?

This question does not make sense. You can put the normal map on any lowpoly mesh that you produce, you can generate the normal map using the original lowpoly object or the retopologized one and afterward assign it to either of them.

The retopology process is merely there to alter the topology of the mesh, e.g. this can be necessary if the highpoly object in zbrush was modelled from zspheres and the normal map has to applied to an object that will be animated. The topology from the lowpoly zspheres object will most likely not be suitable to use for animation because of the automatically generated topology and therefore has to be redone so the animated object deforms correctly.

This process has nothing to do directly with maps that will be assigned to the object afterwards, therefore the question "retopology or map?" does not make any sense at all.

meleseDESIGN
04-28-2010, 02:54 PM
I generate the normal maps with zMapper from an high-poly object.
After I have generated the maps I export the object from zBrush at Level 1 to Maya.
Back in Maya I apply the maps to the low-poly mesh. As a result i get a high detailed low poly model without to go through the retopology process.

ezekiel66
04-28-2010, 03:14 PM
I generate the normal maps with zMapper from an high-poly object.
After I have generated the maps I export the object from zBrush at Level 1 to Maya.
Back in Maya I apply the maps to the low-poly mesh. As a result i get a high detailed low poly model without to go through the retopology process.

How did you create the low poly object that you have imported into zbrush in the first place? In Maya?

Again: the retopology proces is there to modify the topology of the object (the edge flow). This has nothing to do with normal maps. Retopology has nothing to do with high details, in fact during the retopology process you create an object with low details.

If the topology of your lowpoly object is correct to begin with - because you have modelled it in Maya - there is no need to do retopology in the first place. You only have to redo the topology if the topology that is there already is not usable for the purpose of the object. Of course you can create a normal map using the level 1 object from zbrush and import that into Maya. If you are satisfied with the topology of your object then thats it. No need at all to retopologize.

Maybe there is some kind of misunderstanding here that I can't see...

meleseDESIGN
04-28-2010, 03:37 PM
Yes, I created the low-poly model in Maya, imported it into zBrush and created the details aso.
So it seems begining to model in zBrush and then retopology is the better workflow because it's faster. Is this correct?

ezekiel66
04-28-2010, 03:50 PM
Yes, I created the low-poly model in Maya, imported it into zBrush and created the details aso.
So it seems begining to model in zBrush and then retopology is the better workflow because it's faster. Is this correct?

No. There is no better workflow. It depends mainly on your preference, how you like to model.

You can model the lowpoly object in Maya. The model will have a certain topology obviously, if you are satisfied with this then there is no need to retopologize after you have added the details in Zbrush.

If you have altered the object in zbrush too much, added details that differ too much from your lowpoly object from Maya (you have added some antennas to the head of an insect in zbrush using the snake hook brush for example) then you cannot use the original lowpoly object any more to generate the normal maps from it. you then have to rebuild (retopologize) the lowpoly object so it has the antennas built into it.

Or you could e.g. create a sphere in zbrush and work on it to form it into a human head. Even if you switch to the lowest subdivision level afterwards, importing this object into Maya will be of no use, especially if the object is intended to be animated. It still has, although distorted into the shape of a human head, the original topology of the sphere which is not usable for animation.

In the human face it is important that there is a special edge flow present, so the surface deforms well when the head opens its mouth, or the eyes are closed. The edgeflow has to imitate in a way the directions/ flow of the muscles beneath the skin of the face so the deformation of the face looks natural when animated.

Take a look at this (http://media.photobucket.com/image/face%20topology/Monkey_Knife_Fight/EdgeLoop3.jpg)picture for example. If you have modeled your human head from a sphere in zbrush you will never ever get an edge flow like the one seen on the picture when you switch to the lowest subdivision level. You have to recreate the topology, at least if you plan to animate the lowpoly object.

meleseDESIGN
04-28-2010, 04:28 PM
Ok, i see.
I wasn't aware of this, because I didn't need to retopology so often yet, since I mainly created the base mesh in Maya or C4D and I didn't put to much details on the base mesh in zBrush, not so much that I couldn't use it anymore.

Yes, the mesh structure of an face is near impossible to get in zbrush without to retopology it.
That's why I allways did the base mesh outside of zBrush.

I really need to go deeper into the topic of retopology, since I prefer to make use of it more and more in zBrush.

Would you even say retopology is all I need and I shouldn't waste time for modeling the base mesh outside of zBrush any longer?

ezekiel66
04-28-2010, 06:05 PM
I really need to go deeper into the topic of retopology, since I prefer to make use of it more and more in zBrush.

I always recommend to use Topogun (http://www.topogun.com)for this, its only ~80€. There is a retopology tool in Zbrush, but its quite cumbersome and not that great. I never used it much.


Would you even say retopology is all I need and I shouldn't waste time for modeling the base mesh outside of zBrush any longer?

No, as I said: it all depends on how you like to work. You should explore every method available and find the one that you like best.

One method would be to build the lowpoly object entirely in Maya, then export it to zbrush for sculpting.

Another method (which I personally like a lot) is to just sculpt away in Zbrush using zspheres/ zsketch, and worry about topology later.
For some it might be easier to control the volumes of their object/ character this way. It's just a different approach. In the end, only the outcome matters. How you got there doesnt matter.

meleseDESIGN
04-28-2010, 08:54 PM
I've heard about Topogun a few times allready, but I've never tried it yet.
Is it kinda a tool what does the retopology automatical?

What about the projection function in zBrush, can it be used for retopology as well?
Would speed up the process.

Actually I like to model the base mesh in Maya very much.
But you're right, I have to try out the other ways to make the right decision which method works better to me.

Danke für Deine Hilfestellung.

:)

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