Exporting fbx while keeping sharp edges

Hey guys, I have a car model and I want to unwrap it in RizomUV, but also keep sharp edges while exporting. I’ve already tried to export it with different smoothing options in geometry tab (normals, face, edges - nothing works), also I’ve tried to add Edge Split modifier, it’s worked, but it messing my model, before the modifier it had 136,042 vertices, after - 173,771. So, how can I export it properly without messing up my model?

Shading is done using normals, which are constructed during modeling. Select the edges you need to remain sharp, then go to Edge > Mark Sharp. This has nothing to do with exporting FBX or not. The exporter only tries to include more or less information in the exported file, it doesn’t do smoothing.

If you want all your faces to be sharp, a simple way would be to select your entire model, go to Face > Shade Flat, export it, then just hit undo.