I have an fbx file of a car model I purchased from unity store. The mesh is triangulated and vertex count is 120K. I need to bring it down to 30K . Here is the things I tried. 1) used instant meshes but It doesnt work well with rim and tyres and wiper etc. 2) brought mesh in to zbrush and zremeshed it . It ruined small parts of the car. So second time I brought only large parts of the mesh and It went fine.
But still I could reduce only 30K vertex. My last option was to defimate every thing by factor of 0.5 . Thus I reached the target but It ruined all my smooth shading when I imported it in to unity and 30-40% of my mesh looks black.
Right now retopology looks best option for me. But I have to do same thing for 20 another models. It is going to take lot of time and money. What do you suggest?