I am drawing a helix with extensions in each end (inlet outlet pipes to a coil for a heat exchanger). I would like the part to work parametrically or be able to make multiple configurations. So I should be able to adjust the number of coils, spacing on the inlet, outlet. etc.
The problem occurs when I change a parameter such as the number of rotations on the helix to non-even numbers to test the part and evaluate different configurations, The helix and the inlet/outlet lines are connected with curves that have a tangent constraint. For some changes, the lines turn 180 degrees so that they converge on a tangent point instead of continuing smoothly from one curve to another. An alternative (and valid) tangent solution to the constraints would give the correct geometry.
Included are 2 part files. "Condenser Coil 2.sldprt" is correct. For "Condenser Coil 3.sldprt", I changed helix revolutions from 10 to 9.75. The problem is at the bottom of the coil.
Any ideas on how to force the correct solution?
Marty,
It would appear that the whole tangent issue seems to be because in one of your sketch you might need something with a horizontal sketch relation but in the next configuration it actually ends up needing to be a vertical sketch relation. I have attached the way that I might work around this....not to say that it is the correct way (someone may have better solutions for you).
I created two parts. One for your main helix and the other for the part with which you're having trouble constraining. Attaching with mates instead avoids the sketch relations that fail and i have just added a cut extrude within the assembly to keep your length equal within each configuration.
Not sure if this helps you.
Harmony