Imported Mesh Collision Problem

[cerealmarrow100]

Hello Devforum, (first ever post here) I want to have a collision mesh for a level I am importing from blender as an FBX file

The problem is that despite the fact I set the collision fidelity to PreciseConvexDecomposition, the collision is still like a Convex Hull

However in Blender this is not the case when I make a rigid body simulation.

All faces are visible, the problem is not blender’s mesh collision as the rigid body had no problem when shape was set to “Mesh” so I think the problem is when I import the mesh, but I cannot see any settings that may fix the problem

I tried looking for solutions on Google, YouTube, DevForum, DevHub and Blender Manual itself but cannot find the solution, I tried several settings but I cannot find any that seem to fix it. I also tried exporting the mesh as an object file but that made it get imported worse
I think that the mesh is imported or exported as a Convex Hull even if I set the Collision Fidelity to “PreciseConvexDecomposition” but I don’t know how to change it to a Mesh Collision like the Rigid Body.
When I import, I apply none of the pop-up options (specifically the 1st and 3rd ones), if that helps.

[s2newton (LaurelFox)]

I dont know how to figure out this hmmm.
Maybe you could try separate mesh and group them in roblox and did precise it always happen if mesh huge example mountain mesh

Or if your mesh flip maybe try doubleside it a bit help

[cerealmarrow100]

I separated the mesh so it wouldn’t be scaled down as the mesh is larger than 2048 studs and I cannot scale it down as it would ruin the level collision so I don’t think I can union it. And I already double sided it

[Pokemoncraft5290 (Based)]

It might have something to do with the fact that the walls have zero thickness. If solidifying the mesh doesn’t work, I would just make manual hitboxes with parts.

[cerealmarrow100]

Thanks, tried it, it worked. You my friend are my first ever solution.