# Articulating geometry constrained and dependent

sdl.3dm (2.9 MB)
sdl.gh (11.6 KB)

Hello, I am trying to make this geometry articulate. The top and bottom need to remain the same dimensions and on the horizontal lines that they are, whilst the length will change from 50 to 50.5 etc. which makes the entire sketch rhomboid due to the top and bottom being fixed on the same horizontals. How do I create a function to control the changing vertical length and make its value dependent on the severity of rhomboiding of the sketch?

thanks!

I can’t open your R7 .3dm file in R6 and can barely read your tiny diagrams. They say 500 to 505 (I think?) while your description says 50 to 50.5?

Does this help?

articulating_geo_2021_Jul31a.gh (13.3 KB)

Thanks for helping!! Why have you used the circle to generate the point coordinates?
This is what I am after, however, I need to be able to keep the red line fixed at 500 no matter what the other dimension (500 or 505 etc) is changed to??

One of us doesn’t understand this request… Your initial requirement was:

It isn’t possible to have a fixed length edge line (500) while moving the top (or bottom) horizontally unless the top and bottom move closer together or farther apart.

More context is probably helpful, the material of the sketch will expand, because the top and bottom dimensions are fixed it forces the expansion horizontally, only the left side will be expanding therefore, the right side always stays at 500. So I need to get the left side expanding whilst the right side remains 500 and the top and bottom are fixed parallel.

No. If “the top and bottom are fixed parallel” AND “on the horizontal lines that they are” (so the distance between them cannot change?), then what you are asking is impossible.

articulating_geo_2021_Aug6a.gh (6.8 KB)

P.S. This is not the way I understood your descriptions… but it satisfies some constraints?

articulating_geo_2021_Aug6b.gh (12.8 KB)