I got started using a curve and an array, but the curve is not great, it’s not well connected. If you take a sinewave and repeat and offset it the right amount with the right length then you can recreate the pattern. How would you recommend modelling the spiral / sinewave / weave part of the collar?
Make sure to activate the Extra Objects add-on included in Blender…
Shift + A …Mesh…Math Functions…Z-math surface… use this as the math z-equation sin(x)
…and control length with the x-axis input
Now what I did was to do this and then delete all but a single edge loop…
Convert to curve…it works a bit better if you use Vertex Slide (Shift V) in edit mode and line up Vettices along the top and bottom of the sine wave… merge any too close…smooth etc…
then you can go back to object mode and duplicate and move to get your braid…
By adjusting the curve over and under there you go…
this has a subdivision modifier added to each section…
I started a new one using array modifier in order to weave a single portion and then repeat the weave, and I got it mathematically perfect by ensuring the points sampled of the sine wave line up with the grid but the problem is the array modifier is not connecting the curve.
The problem is the way that curve modifiers work. it is fully evaluating the curve bevel profile, then sending that geometry to the modifier.
Alright how about this. Let’s forget about using curves. Start with a triangle wave of vertices, subdivide to get a sinewave, then there must be an easy way to get the “skin” / belt shape from the single edge?
Skin modifier
skin modifier doesn’t work, it is unstable with array modifier, makes no sense.
I had to adjust your sine wave as it was off by a bit…
added simple arrays to what I think the pattern was you wanted…
added a simple deform bend…
Very Nice!
Just have to watch reaching for your wallet! 
