Flat Plane being warped

I uploaded a flat plane mesh today to use in place of blocks which only have one visible face, but it appears that the engine warps the mesh so that there’s vertices in opposite corners to allow it to scale in all directions, which is forcing my totally flat horizontal plane to be crooked


Repro steps:

  • open blender
  • insert plane
  • export as fbx
  • import to roblox meshpart
  • meshpart is crooked

I am unable to replicate this. How large is your plane exactly?

Scale it in the Y direction, if the size is Y=0.05 you’re not going to notice it looking at it like that. Or clone it and compare them side by side where edges should be lining up. You’ll see a difference

Roblox does this because any part cannot have a dimension of 0, which a flat plane does.

When you import a mesh, its bounding box is the size of the mesh and also corresponds to its size in the properties panel. With a flat plane, that y dimension would be 0, which Roblox does not allow. You have to give it some thickness.

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I am still unable to replicate the issue. Exactly how large did you scale your plane?

Edit: I’m receiving similar results as the person above. However, your image looks very different, so i cannot ensure that we’re talking about the same issue. If it is, then that’s your answer.

The plane in the screenshot is literally like 3 x 0.05 x 1

@qqtt991’s gif represents exactly whats happening to me

Consider trying this instead.
This is a flat plane with a second flat plane very close beneath it and scaled down as small as possible. In Roblox it technically has a thickness, so the issue no longer occurs.

However, if you make the part very large it’s possible you’ll see the second plane, unless you ensure it’s always kept very thin, or the underside is always out of view.

fixed_flat.fbx (22.0 KB)


Edit: My bad, i keep forgetting Roblox has that 0.05 size limit.

Have you attempted to use specialmeshes? They are the most convenient to override the size limitations (although I hear it has an effect on performance?) Otherwise, I’d suggest sticking to solidified planes (and you can adjust the thickness from there, even down to 0.00001 or something)

If you’re going to be positioning these by script then it’s possible that you can use these as MeshParts even with it stretching from the bottom edge to the top edge. You just have to compensate for it with the part’s CFrame. It’s a lot like making a WedgePart’s angled face be a certain position/size.

Alternatively you can do what nurgenius suggested and use a SpecialMesh with a Y size of 0. I’m not sure what disadvantages SepcialMeshes have. I think there might be lower performance than when using MeshParts as they don’t receive some performance optimizations.

The problem with both of those is I’m not using it with scripting, I’m using these for building. specifically using these for street lines for a city build I started for fun, because if can use 1/8 as many triangles I might as well right

Special meshes don’t scale like meshparts do which is not useful to me