Why UNITY Scene View Becomes so SLOW?

Hello! Good am/pm, My FIRST issue is when i tried adding an FBX file or 3D model/objects to the scene view it become so slow but when i enter play mode everything is fine but when i exit the play mode its becomes slow. Why is this happening in my scene view? it would be kindly if someone answer, THANKS :slight_smile:

Which model u are using? How much vertisis it have? Game Engines have problems with high amount of vertisis. Did u try to add the model in a fresh project? If u have a low amount of vertisis (~0-5000) and it’s not better in a fresh project try to re-install Unity.