Collision Mesh for Meshpart has GIANT holes in it when set to Precise fidelity

[Maxwell_Edison]

We are having a pretty bad problem regarding meshparts we are using for terrain.
These meshparts, when set to PreciseConvexDecomposition Collision Fidelity, have giant holes in them.

We do not know why. This makes it so we have to do a lot of effort to patch holes in the meshparts.

I am used to collision inaccuracies, but literal holes in the middle of the meshparts seems like a huge bug.

When using the default collision fidelity, there are no holes in the collision, but this is not acceptable levels of collision detail for us.
(And even if it was; this is nonsensical and should be addressed if possible!)

The meshpart in question is uploaded here (Hopefully it’s viewable, I don’t really know if the mesh needed to be uploaded to roblox separately to the meshpart, let me know if this doesn’t work) https://create.roblox.com/store/asset/103529880299584/Landscape-7

Also in file format
MeshFail.obj (770.2 KB)

[LostShedGames]

I’ve found that precise decomposition has a problem if the complexity or poly count are high. You have a few options:

split your terrain mesh into many small submodels as I did here What are you working on currently? - #2620 by LostShedGames

Duplicate your mesh into transparent collision patches… I saw a post on here from someone who broke it down into individual trias, but it seems a very inefficient approach to me.

Create your own simpler collision mesh that is a just good enough resolution to stop the player falling through the terrain.

Do something with wedges to give you a collision surface. Big overhead.

[Maxwell_Edison]

Yeah, we’ve considered options like this, but I thought it’d be best to report it as a bug, because it feels like holes in the mesh is an outcome that Roblox should definitely seek to avoid.

[LostShedGames]

Fair enough, it certainly should not leave holes.