Tutorial for LSCM UVs (Unwrap 3D Pro)
Simply speaking, LSCM UVs (Least Squares Conformal Maps) is a tool to help minimize texture distortion without introducing a lot of seams.
Seams are edges along where UVs are discontinuous.
In Ultimate Unwrap 3D, the LSCM UVs tool relies on how your 3D model is connected,
so it is best to weld your model's faces before proceeding.
For this example, we will use the face of Beethoven to demonstrate LSCM UVs:
In Ultimate Unwrap 3D, the highlighted green edges show where boundary edges are located on the model.
Note that for this specific example, it is not necessary to mark edges for unwrapping, as our seam
is already defined by the model's boundary edges.
Now, click Ctrl+A to select all faces, then click 2D Tools | LSCM UVs:
As you can see, the model is now unwrapped, however, the UV mapping is not perfectly symmetrical.
We can solve this problem by pinning UVs. When a UV is pinned, its position will not move when
LSCM UVs is applied.
However, what UVs should we pin? Before going further, let's first explain how the LSCM tool
works behind the scenes. When no UVs are pinned, LSCM will project your model's vertices
to a mapping plane by default. Then, it will pin two vertices: the maximum and minimum. So, to get similar
results, we should pin at least two UVs, ideally at opposite poles. And then let the magic of LSCM
fill in the missing pieces.
As shown above, we will pin the top and bottom UVs that are located along the centerline of Beethoven's face.
In vertex selection mode, click Edit | Pin | Selected UVs.
To insure that the two UVs are aligned vertically, click Edit | Straighten | Vertical to straighten them out.
Now, in face selection mode, click Ctrl+A to select all faces, then click 2D Tools | LSCM UVs again:
Now, our UV mapping is symmetrical along the centerline of Beethoven's face.
Finally, if we assign a material with a checker texture map to all faces, we can see that there is minimal texture distortion,
which is good enough for most purposes:
We learned how to use the LSCM UVs tool to minimize texture distortion and how
to modify the UV mapping by pinning UVs.
That's it! If you have any other questions about LSCM UVs, please let us know.