[Q] WOndering why UV's are flipped when OBJ is imported

Ive noticed recently that models which are exported from Cinema have the UV islands flipped, same is for the model. Im not sure what kind of import setting is best here.

Other OBJ files where i dont know from which app they come seem to be just fine. I see this quite often when i model something in Blender as well. When i unwrap the model the UV is flipped.

Is there a workflow how i can prevent this?

I’ve read that R17 has issues with flipping UVs on obj export, but I’m not sure what you’re dealing with exactly. When you say that the UVs are ‘flipped’, do you mean within the (0 to 1) UV bounds or (0 to -1)?

Basically, there are no current import settings to avoid this. You can always write one in for yourself, though. The UI portion of the obj import/export is in Blender\2.77\scripts\addons\io_scene_obj_init_.py so you could add yourself a button there. If you wanted to manipulate the way the UVs are interpreted, edit import_obj.py

def handle_vec on line 885 would be a good place to intercept the data. Hopefully that gives you a place to start.

well it seems the UVs are flipped over Y-axis. I use a special OBJ exporter and havent seen it with all models though.

I also see it a lot with models made in blender. When i unwrap them the uvs are 9 out 10 times flipped over Y axus

So, even if it’s the Y axis, rather than X, in what way are they being ‘flipped’? Are they being flipped out of the (0 - 1) range or within? You must provide more detailed information, images, video, or .blend files so we can understand what you’re talking about.

Blender unwrapping should not be flipped unless your face normals are flipped. I can’t recall a single instance of the UVs inverting as you describe. Not unless I invert them myself, or invert face normals. Do you mean rotated 180? What method are you using to unwrap your models? At what point during the unwrap do you typically discover if they’re ‘flipped’ or not?

Without visuals or more specific information, there’s not much we can give you advice on.

Sorry im new to all these special things, i believe the o,1 range is important isnt it. Its flipped within (0-1) range, so within the normal UV viewable area. Ill try to make som e screengrabs for better understanding