Custom Collision for Skeletal Mesh Vehicle causing big Frame Rate drop. Help pls!

Hi everyone! :slight_smile:

My game features pilotable spaceships and those spaceships are Skeletal Meshes because they need to have animations. So of course these spaceships need a Custom Collision object inside Unreal PHAT.

So I have made the Custom Collision as a Static Mesh inside my 3D modelling software, and made it as simple as possible, but still able to cover the body of the spacecraft. Currently the Custom Collision Static Mesh is 668 Triangles (As opposed to the spaceship itself which is 25,000 Tris.) So I import the Custom Collision Static Mesh into UE4 ( auto generate collision and one convex hull per ucx - unchecked ). I make a new Physics Object for the spaceship, delete all the physics objects except one, and then “Copy Collision From Static Mesh” and delete the one left over collision object, leaving only the Custom Collision Object which is considered as 1 body and has 103 convexs.

Everything seems fine, however having 8 of these spaceships with custom collision in the scene causes a Frame Rate Drop of 30fps. IE the Frame Rate is normally 70 fps but with the 8 spaceships in the scene the fps drops to 40fps. If I delete the Custom Collision and just give the spaceship 1 cube as a collision object then everything is fine 70fps as normal. But with the Custom Collision for these spaceships, the game always loses 30 fps - which of course is un-usable.

Does anyone know why these Custom Collision Objects are causing such a terrible hit on the Frame Rate? I use similar complexity Custom Collision objects for all my environment static meshes and they cause no problems at all.

Does anyone know of a way to get a decent Custom Collision for my spaceship without a massive hit on the Frame Rate. Any advice or help would be greatly appreciated. Thanks a bunch! :slight_smile: