How can I export to zbrush and import back retopo model properly?

Kirkr · January 17, 2023, 2:29pm

When I export fbx from reality capture, do retopo and import it back to reality capture it never matches the initial model, always rotated . How can I do it right?

OndrejTrhan · January 17, 2023, 3:48pm

Hi Kirkr, after opening the model in Zbrush do you rotate the model somehow?
Can you try these settings when you are exporting model from RealityCapture:

Steadcraft · January 28, 2023, 3:26pm

The important thing is export with .info file from Reality Capture, do not move or rotate in Zbrush, and save over the original RC export (same name) when exporting from Zbrush. Make sure the .info file is alongside the model (recommend fbx format) when it is imported back into RC as a component.

Steadcraft · January 31, 2023, 10:02pm

Or so I thought–now I’m in the same situation.

OndrejTrhan · February 1, 2023, 7:54am

Which export settings have you used?

Steadcraft · February 2, 2023, 1:37am

I have sorted my situation, thank you.

I initially exported with the same as in your image example except that Scene Transformation was default with no rotations. This resulted in models that would always come back with transformations when cycled through the Zbrush FBX plugin–regardless of settings (and with no other transforms or moves in Zbrush).

OBJ files survive the round trip without being transformed.

In my case, I was able to reimport my problem files by following this workflow:

re-export all models as OBJ from RC with -90Z and -90Y
re-export from Zbrush previously problematic models (which were imported as fbx with MayaYup via fbx plugin)
rename the obj.rc.info file to match the new OBJ from Zbrush
import model into Reality Capture.

Kirkr · February 2, 2023, 5:48am

Nope, that Z -90 rotate doesn’t fixes it. And I do save over same fbx with same name and fbxname .rcinfo is present ion the same folder.

So it still doesn’t work for me .

BTW, what up option should I choose when export fbx fron Zbrush ? Maya Y up ? it’s default one I think.

OndrejTrhan · February 2, 2023, 8:14am

Can you try Steadcraft’s solution?
As RealityCapture uses Z as up direction, this could cause mentioned problems.

Steadcraft · February 7, 2023, 3:24pm

I would add one more critical point. If your RC project has more than one alignment, be sure you select the same that you exported from before importing your model back in–otherwise it will be grouped with the wrong alignment and will be misaligned.

Steadcraft · February 7, 2023, 4:09pm

And I would say that the -90Z -90Y export transform is now my default setting. Round tripping the files is flawless (in OBJ).