What happening about collision has double edge?

Hello everyone ,I got some problem about collision every model i found this problem.
Everyone please me.What is it.
how to fix it? Thank you very much.
220250-

when i export to unreal engine my collision got double edge.i don’t know how to fix.

I dont think you need to fix this but on a cube if you just want a cube collision box you can first delete your old collision with Collision → Remove Collision. And add a cube collision with Collision → Add Box Simpliefied Collision.

Thank you for answer. "What about complexed shapes? like making collision for cars, some shape can’t be just a cube, but rather asymmetry geometries.

And do you know any plug-ins or software that can check convexity shapes which also compatible with unreal? I used max convex script, but somehow it didn’t work quite that well.

You can rebuild complex shapes in unreal by pressing Collision → Convert Boxes to Collision.

That should open up a little tab bottom left where you can change some setttings and rebuild your collision.

There is also a way to export from your 3D tool with collision, maybe you wanna try this

still not working yet. T T