MeshParts with different orientations but same LookVector

[rogeriodec_games]

Reproduction Steps
Run this: LookVector.rbxl (38.9 KB)

Expected Behavior
LookVector for P5 should point up (0, 1, 0) and P6 should point down (0, -1, 0).

Actual Behavior
Both are with LookVector on Z (0, 0, 1).

Issue Area: Engine
Issue Type: Other
Impact: Critical
Frequency: Constantly

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Some days ago I opened a Build Support topic with this problem:

Problem: Parts with different orientations but same LookVector

I have this Main part, made up of 6 inner MeshParts, each one pointing in a direction, like the faces of a dice: [image] When running this script, you can see that parts 5 and 6, even with opposite orientations, have the same LookVector: for _, Part in ipairs(workspace.Main.Parts:GetChildren()) do print(Part.Name, "Or:", Part.Orientation, "LV:", math.floor(Part.CFrame.LookVector.X),math.floor(Part.CFrame.LookVector.Y), math.floor(Part.CFrame.LookVector.Z)) end P1 Or: 0, 180, 0 LV: -0 -0 …

It’s an illogical problem, but I thought I managed to remedy this problem by recreating MeshPart P5 and P6.
I don’t know what’s happening, but the problem happened again.

As the result of LookVector to P5 and P6 is incorrect, I can not continue my program.

[steven4547466 (Steven)]

Well…

These are correct vectors, one’s front face is positive z the other is negative z

Fixed by rotating the front face to face the proper way:

TL;DR: Not a bug, the front face of the mesh is incorrect.

[rogeriodec_games]

Thanks, but where is this “Face Selector”?

[steven4547466 (Steven)]

It’s a plugin

Part Face Selector - Roblox

Also, whoever made the mesh seems to have not aligned the front face with the actual seeming front face. Forward in roblox (in world space) is along the -Z axis.

[rogeriodec_games]

Thanks again, but this plugin only show the face.
How to fix it?

[steven4547466 (Steven)]

Well after doing some very basic testing in blender it seems that the front face needs to be along -Y axis before exporting. With other software, I wouldn’t be able to tell you.

or perhaps this will help:

Mesh Face/Normal Orientation Blender 2.8

If you ever had the issue of faces not facing the right orientation once importing them to roblox heres is your tutorial: Select all your meshes with A+A in edit mode. [image] [Captura] Click there, and search for the button FACE ORIENTATION. [image] Like in the image above, do you see all those red faces? they are the ones causing the issue, they are looking inside the mesh, not outside. Once all your mesh is selected press SPACE and write RECALCULATE NORMALS, [image] Press that but…

I’m not very experienced in blender, but it does not look like a bug to me

[rogeriodec_games]

You solved a big problem I was facing and I had even created a series of workarounds via script to try to get around this problem.
Now everything is more logical.
Thank you very much!