Questions about Mudbox workflow (baking)

#1

I used the 30 day trial for the old version several months ago and just downloaded the 2009 trial a few days ago. I find myself loving this program and although I am quite new to scuplting it seems very intuitive.

The reason I’m posting here is because a lot of the training material online is for the old version and I notice several interface changes. Most of my questions here will be about the texture extraction feature.

So today I was working on this pillow for a small living room scene. My workflow was as follows:

Create base mesh in Max
Export obj to Mudbox
Subdivide 7 levels and sculpt
Export level 2 subdivision back to Max
unwrap level 2 subdivision, export back to Mudbox
try to bake a normal map from level 7 to level 2.

This is where I had the problem. First I was running into all sorts of glitches and wierdness which are probably just symptoms of not knowing how the program works. My main issue was that I am unsure how to go about baking this map. Should I export level 7 and level 2, unwrap 2 and then import them back in and bake?

I would love to be able to just bake from my sculpted mesh in Mudbox but there aren’t any UV’s on it, this is the reason for exporting back to Max. Is there a way to unwrap a mesh in mudbox?

If anyone has any tips or tricks or advice on this workflow I would appreciate it, especially since this board seems quite dead.

#2

Although this is for displacement, not normal maps, most of your questions are answered in this tutorial…

http://www.neilblevins.com/cg_education/mudbox2_max/mudbox2_max.htm

  • Neil
#3

Thanks a lot! I just got lost on your site for an hour or so reading other tutorials but the one you linked me to looks promising so I’ll read it in depth once I get home. I actually ended up having better luck last night with the baking, it seemed my objects weren’t quite lined up and this was producing a lot of the errors.

#4

Neil, Thanks for the tutorial. Yesterday i tried for the first time to export displacement maps (before reading your tutorial), and in creating the tile it always hung up on 86%, even though my system resources weren’t even nearly exhausted. The way I did it was only having one object, and selecting the low subd version as the target and then choosing the high subd version as the source. The way I understood your tutorial, I actually need to have 2 copies of the object (one high and one low subd). Is this right? Is this not going to be a bit heavy when having bigger objects with a poly count of 4000 000 due to high subd?

#5

That is actually what I ended up doing because I had to export back to Max for an unwrap, then export into Mudbox again. If the mesh is already unwrapped I don’t see any reason why you couldn’t just bake from 1 object, although I haven’t tried it.

#6

You don’t NEED to do this, but it helps. It really depends how low res your lowest subdivision level is. Think of it like this. Your goal is to get an exact replica of your highres object using your lowres object with a displacement map. The accuracy you’ll get using a level 0 mesh might be 20%. As you move up the subdivision levels, your odds get better. Like if you use the Level 1 mesh, you might have 50% accuracy. If you use the level 2 mesh, you may get 95% accuracy. The downside of course is the more subdivided your lowres model is, the more polygons you’re keeping in your 3d scene. So you don’t want to go too far. But personally I have found that using a level 1 or a level 2 mesh as my new lowres means my final object with a displacement map will look very very close to my highres mesh, using level 0 rarely gives me an exact copy, because it’s just too low res.

But it’s worth experimenting. My Level 0 meshes are usually very light. Maybe your level 0 mesh has far more polygons than mine, and so you’ll have better accuracy without exporting a level 1 or 2 mesh.

But anyways, that’s why I usually recommend exporting a level 1 or 2 mesh, and then calculating your disp map as the difference between your level 1 ro 2 mesh and your highest level mesh. Again, it’s not necessary, but I expect you’ll get better results.

Since your level 1 or level 2 mesh should still be pretty low res, like maybe only 2000 polys, having a copy of that in your scene as a seperate object shouldn’t increase the filesize or slowness much at all.

  • Neil
#7

You don’t need to do that anymore, mudbox now lets you import uvs only from an obj, so unless you’ve radically changed your topology when sculpting, you can just import uvs from your original mesh, you don’t have to export out your lowres mesh to give it uvs.

See my explanation above for more details on why you’d use 2 objects.

  • Neil
#8

Hmmm, ok. Does anyone know then why it keeps crashing when I try to extract the maps? I am using the 64 bit version and have 8Gb RAM and a Intel Quadcore. When it crashes it does not even use half the RAM and half the CPU. It just stopps. The model I want to extract from has about 1 000 000 Polys, so not even that much…

Or does it usually take longer than 45 Minutes to extract? (theat was how long i waited before i gave up).

#9

Try to use the paint tool if mudbox crash when you create the map for painting then you’re model has a problem (ngon probably maybe bad uvw).

And it takes few minutes to get a displace map (not 45min).

#10

Alright, but aren’t you able to bake from a mesh using it’s subdivision levels? So if I had a mesh sculpted couldn’t I bake a displacement from level 8 subd onto its level 2 geometry which means I am really only using 1 “object?” Or are you suggesting to export the low res geometry and the reimport it to get two objects. I know in Zbrush with Zmapper you can say “target mesh = level 3” and “source mesh= level 8” and just bake that way from the same model.

Also then, if you brought in a very very simple base mesh, say just a box with some segments for the couch cushion I did, the level 2 SubD is actually what I want in my scene. Unwrapping a box at level 0 wouldn’t give me decent Uv’s at all, thats why I was re-exporting level 2. Hopefully these questions make sense since I got the correct results doing this method, i’m just not sure if it’s the most logical way.:slight_smile:

#11

Yup, you could do the same thing in mudbox 1, but mudbox 2 doesn’t have that ability. Until they add it back, you’ll have to use this workaround.

Well yes, if your lowres mesh is too lowres, then it does make sense to export a higher level mesh and do the uvs on that. All depends on the model. That’s what I was getting at when I said “unless you’ve radically changed your topology when sculpting”, I think getting a detailed cushion from a 6 sided box would definately count as a radical change. But being able to import uvs means there are now many situaions whewre I can avoid importing in the lowres mesh again, except at the baking stage of course.

  • Neil
#12

Excellent, that answers my questions completely then. I figured that feature dissapeared temporarily but would be back just like Zmapper vanished for a while when 3.0 came out. I thought I saw some tutorial that said you could select the different levels of subd in the object panel or somewhere and use that as a target or source mesh but I guess that was the old version.

#13

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