Handling CAD models

Hello, not sure about nomenclature, but I was thinking how the engine handles CAD models.

Is it better to use cad model with true arcs or will it be polygonized by the engine?

What is better for performance to use CAD model (preffered ofcourse) or do I have to generat low-poly versions on my own?

In Shapespark all the models are imported already in polygonal format. Whether you have to generate a low-poly versions for some of the objects in the scene depends on the total number of polygons in the scene. A few high-poly objects are rather not a problem, but if you have dozens or hundreds of them, it’s necessary to make low-poly versions to keep the scene size reasonable.