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Wavefront exporting flipped normals
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Description

--- Operating System, Graphics card ---
Ubuntu 12.04 64-bit
GTX 590

--- Blender version with error, and version that worked ---
Blender 2.62 - error
Blender 2.65 - error
Blender 2.67a -error

--- Short description of error ---
When exporting the object ERROR as Wavefront and importing it again, the normals are flipped.
When exporting the object CUBE as Wavefront and importing it again, the normals are fine.

--- Steps for others to reproduce the error (preferably based on attached .blend file) ---
Look at the normals of the ERROR Object
Press tab
Export to Wavefront filename.obj
Import from Wavefront filename.obj
Visualize the normals again


Details

Type
To Do

Event Timeline

The object has negative scale on the Z axis, which flips the normals, but Blender will auto detect that and flip the normals outside again. The obj exporter applies the same transformation, but on reimporting Blender can't detect the negative scale anymore because it was applied.

Campbell, maybe the exporter should flip the normals on export if the mesh has negative scale?

If we do this it should be for all exporters that don't support transforms.
added as a todo.

http://wiki.blender.org/index.php/Dev:2.5/Source/Development/Todo/Import_Export