spiral-curve-spiral s-curve, set tangent to length?

[Maverick91]

We use spiral-curve-spiral transitions between tangents a lot. This includes s-curves where the alignment will diverge from a parallel line, then turn back to the original bearing but now farther away from that parallel line. I want to be able to control the length of the tangent between the S-C-S’s. If I just move the curves along the long tangents, trying to have the short tangent between the curves is like trying to hit a moving target. Is there a trick or setting or slight-of-hand to set the short tangent length?

[remi678731]

HI
Try building your curves one element at a time. start with a tangent made the how you normally would then add elements as needed. you will need know the needed curve elements before you start radius delta degree of curve etc.
Just curious why do you want a tangent in the middle between the reverse curves

[Maverick91]

HI
Try building your curves one element at a time. start with a tangent made the how you normally would then add elements as needed. you will need know the needed curve elements before you start radius delta degree of curve etc.
Just curious why do you want a tangent in the middle between the reverse curves

For our work, the spiral lengths and the curve radius may change as we work different options.

We consult on transportation systems, almost entirely for automated people-mover systems -- these are computer-controlled systems like a small train system.