Unusual lines on UV map after using “Difference” to create apertures on a plane

Question

I used the difference procedure to create a “door” and “windows” on a single plane. (placing 3 joined cubes through the plane and using the “difference” modifier to create the apertures) After overlaying the test map the result shows unexpected lines, indicated with yellow lines, on the resulting map. I uploaded the results (Second life) and it appears to look ok.

I could use Loop cuts to get the same result but was wondering if anybody knows what is happening (the unexpected lines) and if this is going to cause issues elsewhere.

I have applied rotation and scale modifier, remove double vertices and reset origin to centre

Answer 1

Using the Boolean to cut the openings left the object with only 2 faces, Filling in these Concave Ngons caused the lines you see in the UV space. If you enable the face select mode this will become more obvious.

These Ngons will not be a problem as such once the object is imported into SL as the importer will convert those Ngons to triangles.

But as FFeller suggested using loop cuts is a much better way to go about this simply because you have more control over the geometry:

And having more control means it will be a lot easier to optimize the model ( = Lower LI costs) , easier to create lower LoD models and Physics model later in the process. So best to avoid Boolean cutting for SL :)