1. Convert any symbol to gruop.
2. Ungroup any group
3. Divide your model by layer. (best if you catalog the layers by textures or material)
4. Put all yor layers Delta z =0, on layers setup.
5. All of your layers must be at top plan.
6. Put our layers "Show others, or show snap oher". No invisble layers.
7. Export DXF/DWG. Using dwg in any version. I prefer version 14. Use text.
8. On export window: Export layers as dxf layers. Select triangulate to preserve 3d fills. Decompose 3d objects. Export all 3d. Don'select 2d options.
9. Open it on strata 3d.
10. You'll see your model catalogued by layers.
Note: 3d conversion resolution on preferences it's important. More resolution more quality and more memory.