Now that we have adjusted the UVs leave a nice map.
Your face sets may be different to the ones shown by the pictures to the left.
Collapse the Stack.
With checker in ID 3 now correctly mapped on the object.
Collapsing the Stack after each Unwrap is not needed but that frees up some resources and we can always improve the UV thereafter...
For the yellow checkerwork (Chechmate ID 4), select with Select ID then UVW Map in mapping Box.
In Unwrap UVW, one sees only one square, makes UV of it are superimposed.
Click on a point then Extand Select.
Move UV to separate it from the others.
Repeat the operation jusquà what there is superimposed no more UV.
The checker is stretched we will regulate it later
Make it the same as the green checker (ID 1).
Select Expand and separate the set from the UV.
For the red checker, place a Planar map it.
We now make a Full set of UVs from all 5 IDs with the whole UV rearranged.
This board could then be used in photoshop to paint a full texture for our object.
In Object mode Select Unwrap.
View all ID's, then move them about until you have know superimposed sets of the UV.
Use Expand Select to put them in order.
Isolate Checker ID 4 and weld the UV vertices, viewing in the viewport will help you repair the orientation of the UV.
Now adjust the UVs so as to correct the formations of the checker.
Remembering that if you select a point and nudge the Weld Threshold up. You should see its matching pair lightup, thus making it easier to lineup the sets as required.
Even everything out for Checker ID 1.
Although we can move, scale etc. as we wish in the UV Editor, we need to make a flat base for the UVs so that those IDs contained in the square are in the center of the UV Editor window.
The coordinates of the UVs must lie inside our gray Square. Beyond this the texture repeats on itself.
Before we scale the set of UVs. Position them in the square so they are coherent in the UV Editor window, i.e. part of the object does not have a mapping too fine and another too large.
Visualize the scale of the sets of UVs so that the whole of the checker has the same size.
Then select all the pieces and uniform scale them to fit them in the large square.
Just position the other sets in the remaining space.
Now we Collapse the Stack for the last time.
Here the goal is to make a single board of texture, and thus make only one bitmap to texture the object.
It is generally more practical to manage because there is only one bitmap file to handle.