Hard surface UV mapping tips? (2.79)

Hi blender people, I’m new to the forums :slight_smile:

I’ve had some problems UV mapping hard surface objects in Blender. I am currently working on this M1911 handgun, and I would like the UV’s to lay out perfectly straight along the slide, but the holes and cuts in the mesh seem to bend the UV’s so I end up with curved/warped UV islands.

I’ve tried unwrapping using “follow along active quads” by selecting different quads as active, but I just get them distorted in a different way.

Does anyone have any tips or common practices for this kind of issue? I’ve run into it several times trying to layout this gun. I can’t seem to upload the .blend file because I’m a new user…

Hi @Calavera, your problems come from trying to unwrap with insufficient seams. Whenever there are areas that both go-in and go-out of the basic shape ( the grip area on your mesh being one) the seams must specifically take this into account. When you don’t then the surrounding geometry has to be distorted to compensate. I wrote a detailed reason for this in a similar post - No edge loop issue with marking seams which you may find useful.

Here’s a quick demo using something like your mesh:

  1. not enough seams and all edge-loops ‘curved’.
  2. :slight_smile:

and here’s the blend file for you to see:

unwrap_example.blend (790.0 KB)

[ Both pieces are identical but make only one mesh - to enable the different UV’s to be seen together.]


Hi Damian, thanks for your reply!
Yeah I completely understand why it’s getting distorted, I have rivets on the sides that push into the mesh at 90 degree angles, and the UV islands bend a lot around those details. I guess what I’m after is a method of unwrapping where it prioritizes a straight UV island and allows some stretching around those areas to compensate for it.

In Maya, I would probably have worked around this by doing a half-dome cylindrical project along the slide to get the shape of the UV island the way I want it, then pin the border and relax the UV’s slightly just to avoid really bad stretching on 90 degree angles. I also get a little bit better results in 3D Coats auto unwrap, but I would really like to stay within Blender for laying out the UVs. Maybe there’s a good addon that can help?

You’re welcome.

If you want to stay with Blender ( :slight_smile: ) you might like to take a look at this:

The best external ( paid for ) alternative that I use when things get really complicated is:-

It’s interface is seriously intimidating and the learning curve is steep . . . like climbing Everest in a sleeping-bag, backwards, at night. But it’s packing and seaming are amazing.

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Aha ha hah! Yes it is.