beginner's question. How to import zbrush project to maya for retopology?

macke

Hi all,

I'm a bit confused with the correct procedure of importing a sculpt from zbrush to maya for retopology. Once I'm done with the sculpting in zbrush do I need to bring down the mesh to the lowest subdivision level before importing into maya, or if  this is not nessesary? Do i need to know anything else? for example do i need to use zbrush decimation and then go to maya for retopology?

thank you so much for your time.

quockhanhlk

people usually keep the high poly model at the level of detail they want the final product to have, in order to retopologize and then bake the detail down. Zbrush decimation has many use cases, but for retopologizng/ baking it is mostly use for optimization of the high poly model. I would suggest you to use the highest subdivision level of the model that youve worked on, if your pc can handle it. If not use the decimation tool to optimize it.
I would also suggest that you look more into the baking process (and the general 'modern' workflow as a whole), because it looks like you havent really understand the why yet, and you're asking for the how atm. Good luck!

macke

Hi thank you for helping me. i haven't looked into baking at all. I'm still quite stuck at early stages of 3d sculpting and trying to figure our correct  workflow to follow for sculpting a character. I would start with sculpting a character, then using zremesher to correct my topology and project the character to bring out the details from original mesh, once that's achieved i would delete the old mesh and continue sculpting on the new mesh with a correct topology. If all of this is correct of the steps i'm currently following then the next step is bringing the mesh into maya for creating uv's. I haven't used zbrush decimation tool yet as not sure if i need to use it thank you for your previous answer

kanga

Yeah you dont need to remesh your zbrush highpoly for texture baking. You only do that if you need extra detail on the hipoly and cant get it at its highest subdivide in zbrush. If you want to bake details from the zB high poly onto a lowpoly version of your model you can do that in Maya bit that would mean opening the highpoly in your 3d app.

Im doing a figure atm and just the blank highpoly is 8 mil points. A fully costumed character can run anywhere between 12 mil and 20 mil points, and being on a humble laptop I dont want to convert those figures to polys by exporting them from zB and try and open them in my 3d app. You can decimate your hipoly for baking but means loosing detail (if thats acceptable to you then stop reading). Using a 3rd party app for baking lets you keep all the detail of your hipoly and the external app will only use the hipoly as reference for baking.

There are literally loads of baking and texturing apps available for this purpose. I use Substance painter, but you can also use Marmoset toolbag for example, and if you want a free program xNormal is super.

The strategy I use for baking textures is:

1/ Make a duplicate/s of the final hipoly/s in zB. If your character has a costume and accessories your highpoly figure could be anywhere from 2 to 20 subtools.

2/ Use decimation master on the duplicate/s and decimate the duplicate/s in stages to ensure the highest level of detail for the lowest polycount. That would be 20%, 10%, 5%, 2% and often down to as low as 1%. Depending on the amount of subD levels the tool has. Subtools with lower levels of division wil collapse at around 2% so keep an eye on the decimated mesh and only decimate to its lowest acceptable level before it collapses.

3/ Merge the decimated meshes (if the figure is constructed from multiple tools) into one mesh.

4/ Open your 3D app and place a cube in the center of the viewport. In this case Maya. Scale the cube to something like 1.8 meters high by 0.5 meters wide and 0.5 meters deep (or the final real world measurements of your character). Make the cube semi transparent for convenience and place it with its base at 0,0,0 in the viewport. I dont know if you have to enable GoZ in Maya, but if you have to do it now and leave the application open.

5/ Reopen zB if you closed it.

6/ Goz the decimated version of your character from zB to Maya.

7/ Depending on how Maya handles GoZeded meshes adjust the position and scale of your decimated mesh by altering the export values at the bottom of the tool menu. You should be able to GoZ your decimated mesh and alter the export values until it fits perfectly into the maya cube. When you have reached that stage save the zB tool and it will save the export settings.

8/ Close zB.

9/ Now you have a decimated copy of your figure in Maya at the right size and position. Retopo your character. Break the character into as many parts as you need to avoid adjacent polys for the final bake. If your final character is to be animated include the right amount of loops in the right position to support deformation. 

10/ Uv the firnal lowpoly/s and export the result/s to a disk.

11/ Open zB and merge all the subtools at their highest subD level so you have a highpoly version of your figure to bake textures from. Depending on your retopology in Maya you can merge the tools into baking groups, like head and hands, shirt and trousers, jacket and boots and so on.

12/ Export the highpoly/s to a destination on a disk.

13/ Depending on what app you are using to bake with you may need to use a plugin for Maya to export your uved lowpoly mesh/s. If you are using an app like xnormal, open it and point it to the low and high poly mesh disk destinations.

14/ Hit bake.

Have fun!

macke

Hi Kanga thank you for detailed explanation about baking  textures. Just so i understand this right, i do not need to remesh my character once i'm done sculpting for baking textures. What about creating uv's should i remesh before creating uvs? Because i understand that i would need to create uvs first before i could get to baking or this not the case? Again thank you for explaining and sorry for silly questions. I'm trying to work my head around the correct workflow to follow.

kanga

Ah ok. The highpoly in zBrush is the mesh with all the details so you dont need to do anything with it except send it to a disk. You make a copy of your highpoly in zBrush and decimate it so you can send it to Maya for retopology (look up retopology in Maya and you will find a youtube vid on it). Retopology is literally drawing a new mesh over the decimated copy in Maya:   http://wiki.polycount.com/wiki/Character#Character_Process or google: zbrush make a game character.

You could just remesh a copy of the highpoly but the mesh wouldnt be ideal for animation or games. You only need to uv your retopologized lowpoly resulting mesh in Maya. Send that to a disk. Use xNormal for example to create textures for the lowpoly using the details from the highpoly.

Its quite a process when you do it for the first time.

macke

Hi Kinga thanks so much for coming back. I think i was just missing a step that i need to decimate the character before it is ready to be sent to maya for retopology. thank you for the link as well, i will get right to it all the best!

kanga