ZBrushCentral

Can I export the low subdiv model and import it back in?

I’m an intermediate level Z-brush user. I use it to create normal maps for game models (so no displacement maps). I don’t have any problems bringing an unwrapped mesh from 3DS Max to Zbrush, detailing it and kicking out a normal map that works fine back in Max again.

I have a workflow issue that I could really use some help with. It could be my lack of knowledge of a certain tool. The problem I have is that I would like to be able to sculpt more on my model. Thus far, I’ve had to resist changing the shape of my original mesh because I want the normal map to align to my model thats waiting back in Max. I need to be able to define my UVW’s in Max. (Also, for that reason, I haven’t been able to use Z-sphere modeling)

Here is what I’m hoping is possible. I would like a way to be able to save the high subdiv level of a Zbrush tool that I’ve sculpted and detailed… take the low subdiv to Max and unwrap it… bring the unwrapped low subdiv model back to Zbrush… (somehow) swap it back in for the lowest subdivision level version of the tool… generate the normal map. Is that possible? I am really hoping for something like this to work, but I haven’t been able to figure it out. Thank you in advance to anybody willing to give advice.

Coquette

Coquette,

It’s kind of funny, I was just watching Gonomon’s ZBrush Production Pipeline DVD. Disk 1 Lecture 5. I too am a new Zbrush user and have been watching these videos over and over again. So, I am very happy that I can help you out with your question.

Several days ago, there was a similar question on my friend’s forum pages. However, it was in reference to forgetting to save a morph target and not having his original base mesh to be able to go back down to. So his normal maps were not aligning up. The fix listed below was a solution to his problem. I think this will also help you out with your dilemma.

(Question from another forum page)
So, you said that you started modeling before you saved a base Morph target. Now you want to be able to go back down to your lowest sub-division level so you can export out you Normal and Displacement maps and not have any issues with them aligning up correctly.

According to the DVD there are two ways to fix this issue.

  1. If there is not an issue with using a new base level as a starting point, save out your tool under a new name like new base model. You can go down to the second sub-division level and delete the lowest sub-division level. You now can export out the new lowest level as a starting base level that you can use in Maya. Then apply all of your Normal and Displacement maps to the new base.

  2. If, the above fix is not a possible solution and you must have
    your mesh exactly the same as your original base mesh that you
    started with try this. Go down to the lowest sub-division level
    then go to tool / import and import the original base mesh you
    started with. This will overwrite the base mesh and put you right
    back to ware you started from. Don’t worry this will not impact
    any of the above sub-division levels and keep all of your work
    intact. At this point you can save out a new morph target and
    continue with your modeling as needed.

So, I think that the solution to your problems would be similar to solution number 2. So, try this. Save out your model I.E your tool and save twice. One you should name it something like High rez, and the other as low rez. Now on your low Rez model you will want to go down to the lowest sub division level and delete the higher levels. Now, you will want to export out your tool as an OBJ object. Now you should be able to take this new OBJ mesh and layout your UV’s in Max like you want. Resave as an OBJ again in Max with you new UV’s.

Then back in Zbrush you will want to load your High Rez tool and go down to the lowest subdivision level and Import you new Low Rez model with new UV’s. You should now have a tool that has all of your work intact and have your UV’s as well.

Note: The above information I have not tried myself. It was just info that I ran across while re-watching my DVD’s for the millionth time. Please take this info with a grain of salt and try at your own risk! Remember always save a copy of your Tool before you try this. The two solutions that were given from Gnomon were more intended to fix a problem with not having a morph target. However, I think that this will prove as a viable solution to your problem. At least I hope it will. Please just save out a copy of your mesh with everthing intact that will not possible be harmed in the process. I don’t want you to loose any of your hard work.

Please let me know if this works for you!

Brian Bouffard

Importing the low subdivision model back into Zbrush with the high detail model active and at its lowest level works out. I am a happy girl and can go on with life now. Thank you so much for your detailed response.

Coquette

Hey Coquette,

I am so very happy that I could help. So, I guess that watching all of these videos has begun to pay off. I am not sure if you have had the chance to watch any of the Gnomon videos on Zbrush or not, but they have really helped me out quite a bit. Thanks for letting me know, Yet another thing to add to my notes should I run across this issues in the future.

Brian Bouffard