How to keep the same size of obj when transferring from one program to another

flipside8404

Hi, I am learning as I go with a school project. I am having some issues with my obj shrinking when moving from one program to another.

I sculpted a high poly in Zbrush
Exported to 3D Coat fro retopo
Exported to Maya to reposition UV's (as I have different subtool and need to resize the UV shell to fit on one UV layout)
Export obj (UV'd/a UV shell resized/reposition) back to Zbrush to project the hi detail on the low poly with UV's

The last part is the one I am having problem with, the scale of the obj from maya is significantly smaller than the original hi poly sculpt I have in Zbrush. I can scale the smaller one using deformation but its not perfectly lined up..is there a way to keep the same size of my obj transferring between the programs I mentioned above?

**I did a freeze transformation in Maya before saving and exporting the obj back to Zbrush..

Thanks in advance for tips/suggestions/or anything that can improve my workflow

Justo

In ZBrush, you can change the scale of the mesh you're exporting in the Tool>Export palette; there's a slider for the scale there.

As for the issue about exporting from Maya back to Zbrush, it's something I personally try to solve always before starting to work: make some test exports with cubes and check that everything's ok...If you're exporting something from ZBrush to Maya to Zbrush, there shouldn't be any scale changes unless you personally use the scale tool or export an fbx with another scale. ZBrush always exports by default the mesh in the scale it came with.

If you know you'll be using X number of apps in your asset and haven't had much experience importing stuff from one app to the other, do so with simple stuff so that you begin to understand what works and what doesn't. Every app has their own personal preferences when importing stuff (for example, working with FBXs with Max and Maya can be a hassle if you don't have the correct scale settings set up for both of them).

flipside8404

Justo wrote: »

In ZBrush, you can change the scale of the mesh you're exporting in the Tool>Export palette; there's a slider for the scale there.

As for the issue about exporting from Maya back to Zbrush, it's something I personally try to solve always before starting to work: make some test exports with cubes and check that everything's ok...If you're exporting something from ZBrush to Maya to Zbrush, there shouldn't be any scale changes unless you personally use the scale tool or export an fbx with another scale. ZBrush always exports by default the mesh in the scale it came with.

If you know you'll be using X number of apps in your asset and haven't had much experience importing stuff from one app to the other, do so with simple stuff so that you begin to understand what works and what doesn't. Every app has their own personal preferences when importing stuff (for example, working with FBXs with Max and Maya can be a hassle if you don't have the correct scale settings set up for both of them).

Thanks for the input Justo. Is it better to do a FBX or OBJ export? What's the main difference between the two?

antweiler

Obj is a much less complicated format than fbx, because it contains less information about a scene. I guess the simplicity is the reason, why many developers like it. It is also a very old (but relieable) format, and available for even exotic softwares. Fbx is constantly expanded and maintained by its owner autodesk.
Afaik, obj doesnt contain some scene information like up-axis or actual size in cm, so these are then interpreted by the app that its is imported to.
With a little pipeline setup (importing/ exporting rules) these problems can be overcome.
I really dont understand why ZBrush doesnt support fbx or at least collada, which is open and features everything that is needed.
edit: oh yes. mostly you can overcome the scale difference by scaling it by 100 or so, wich is easy. It gets unintuitive, when you convert f. e. from inches to cm. Always use the metric system