How to export/convert ZBrush meshes into CAD (Catia) conform (editable) files?

Is there a way to export files out of ZBrush to evaluate
in a CAD App like Catia?

Task is to have a few styling proposals in form of concept
modelings created in ZBrush.
I know I can export it e.g. as an OBJ, FBX, etc… File.
I can open it in Autodesk ALIAS an save it as an IGES, CatPart or STL File.
It´s possible to open that in Catia.
But you can´t do anything in the App with it.
Reason should be, like some technician told me, that this mesh files
are not able to touch in Catia.

When I searched the web I can find a plugin (imagine and shape)
for Catia, which allows to import native OBJ Files.
And with that workflow, the polygons/ SubD´s should be
editable an therefor usable:



However just this addon should cost around 10.000 € in purchse and
2.000€ a single year for subscription.
So it´s not worth even to think about it.

Does anybody have an idea how to get a ZBrush mesh into something
that Catia can handle?
May there is a free app to convert OBJ, or STL into IGES, Step, or CatPart?
Or there is a workaround, or anything else…?

The goal to have the data into Catia is, that you have the posibility to scale the weight of the body and to analyse the technical tension of the different stylings in a very early
stage of product design.

That would be an additional advantage of ZBrush,
beside having 3D Concept-Model Renderings,
before even start with going to create first nurb surface in ALIAS.

Thanks a lot.