UV unwrap cubic wave

In Blender Essentials, the chapter on UV uses the monkey to show how to seam and unwrap a mesh. In class, that takes too much time, so we use a cube. So simple and so squared and easy to see where to put the numbers 1 - 6.

The sticky thing is when we elevate the exercise and use a model shaped as a plus “+” that’s extruded or cut out of a cube. I’ve checked all the vertices and it’s all perfectly squared to all the adjacent vertices. Yet when the model is unwrapped, it waves and does not align like one would expect from a cubic model. Basically, the 90 degree angles warp or shrink.

Why is that?

Have you tried changing the UV unwrap method to Conformal ?

Editing (F9) / UV Calculation tab / change ‘Angle Based’ to ‘Conformal’



Depending on where your cuts are, 90 degree angles might result in overlapping polygons. Make sure you have the right number of cuts in the right places so that you could unwrap it in real-life.