Bug Bug? Or user error? Unity permanently forces transform Y-scale to 0 when reordering in hierarchy

I have a model from Blender. I import it by dragging it into Unity. I add it to the scene and choose "unpack completely" to restructure it. Once I do that, some of the meshes in the model do something weird...

If I create an empty as a child of the model, and then move a mesh to be a child of that GameObject, Unity forces the mesh to have a transform Y-scale of 0. Manually changing this value in the transform part of the inspector to anything other than zero makes the mesh disappear completely. This happens even if I try to move the mesh into the unparented part of the hierarchy.

This happens only for specific meshes in the model; others are fine. Other models do not have this issue. I have no clue what's wrong or even where to look. My suspicion is this is Unity-related and not a Blender file problem... after all, the model works fine when I don't move any of the unpacked assets around.

The video here is a demonstration of the issue.

One other wrinkle - I can make an empty parent of the mesh transform. If I set the empty's Y-scale to zero, the mesh transform can have a Y-scale of 1, and it still shows up (but as if it's completely flat).

Has anyone seen this before? Is this a bug, or do I have some concept wrong that's causing this to happen?

 

I've never seen it, but for blender files Unity actually uses your installed Blender as part of the import process. It is generally recommended by more knowledgeable people than me to use FBX files instead of .blend files for a variety of reasons. You could give that a try and see if you get different behavior.

 

Thanks Joe. I also used .fbx and experienced the same issue.