Hello @Big_Al ,
The units in common export formats are generic. There is no information stored in the file itself specifying whether something is inches or MM. The file only knows that the mesh inside is X number of something.
If you import that file into a program whose internal settings are set to MM, that file will be X mm in that program. If the internal measure is set to CM, then it will be X cm. And so forth.
This will require you to have a good understanding of all programs you are working between, and to set up your scene accurately from the start. GoZ does not change the scale between programs, but you could be working between programs with two different internal measurements. If you have your scale set up in your external program, simply don’t change it in ZBrush, and it should export back into the program at the same size when using GoZ.
Note that while GoZ doesn’t change the scale of imported meshes, it is possible to change their measurements when improperly importing into ZBrush using the conventional import and export functions. Always make sure to select the 3d polymesh star before importing a mesh using the Tool> Import function. This is because it has zero values in the Tool > Export menu. Every tool in ZBrush has scale settings unique to that tool, and if you import a mesh while that tool is active, your mesh will inherit those settings and potentially cause a scale shift. The only time you should ever use the Tool> Import function while another tool with non-zero settings in the Tool> Export menu is active is when you are specifically trying to replace a mesh or to update a lower subdivision level for a multi-res mesh, for instance to update the UVs or restore pre-subdivision vert potions prior to texture export.
In all other scenarios, select the star as an import target, and then append it to an existing tool to avoid scale shifts when using Tool> Import. Does not apply to GoZ.
Good luck!