I've encountered a preplexing situation that I (and my VAR) have been unable to solve. I submitted an ER, but figured I would throw it out here too, to see if any of you might have an idea.

This came up while creating set up sketches for a square umbrella. In order for the umbrella to open and close the combined length of the upper and lower pivoting arms must be equal for the side arms (A + B dims) and the corner arms (C + D dims). See attached part with 3d sketch. Side arm is known; corner arm geometry should be driven by the side arm setup.

This umbrella will be subject to custom configurations based on client needs. If we change the dimension of the overall square (the canopy) and/or the pivot point location in the side arm setup, it would be helpful if SW would calculate the lengths and pivot point locations of the corner arms. This way we will know that it will open and close without binding.

It seems this should be solvable by SW:

1. We know one end point of both C and D lines.

2. We know that the other end points meet along another known line.

3. We know the combined length of these lines.

4. There is only one solution.

Many thanks in advance.