SDL with placeholder values

I’ve been reading a lot of the posts here over the past week, and I have to say there’s no shortage of genius contributors for Grasshopper. Unfortunately I’ve not found any information that could help my technical challenge.

Is it possible to define a SDL line where the direction and the start/end points are not yet defined?

In the attached GH file, I’m hoping I can place a line somewhere on the path of a circle based on the length of the line. So if I make the line longer, the ends should slide out along the circles.

I should say that using circles are not required, as an ARC would work just fine for my application. In the end, I would like to be able to slide the SDL line laterally (using a slider input) and allow each end of the line to follow different locations along the circle/arc.

I hope my intent is clear as I’ve been trying to solve this one for over 2 weeks.

Attachments:

pushrod_sample.gh, 10 KB

Replies to This Discussion

Permalink Reply by Joseph Oster on June 11, 2017 at 7:31am

I don't know what happened... Here it is again, working as expected. When 'AlongCrv' is connected, behavior is consistent; when by-passed, the rod connection jumps between the two intersection points.

Attachments:

pushrod_sample_2017Jun11b.gh, 20 KB

Permalink Reply by Joseph Oster on June 11, 2017 at 8:28am

Oh. What happened is that I used the second circle instead of the first one as the 'AlongCrv C' input in pushrod_sample_2017Jun11a.gh. Honestly, this is what I meant to do in the first place, since the two intersection points are on the second circle, not the first one. It just doesn't work!? Yet it behaves as expected when using the first circle... Hmmm. Guess I don't understand 'AlongCrv (Sort Along Curve)'. :(

Permalink Reply by Joseph Oster on June 11, 2017 at 10:02am

OK, I understand this now. I wrote an alternative to 'Sort Along Curve' using 'Crv CP' and 'Sort' (cyan group below); it works exactly the same as the 'AlongCrv' component! So what I failed to understand is that, due to the geometry, one of the two intersection points moves across the start/end of the second circle, flipping their sequence. This bit of code also shows why using the first circle works.

Using two 'Value List' components, you can choose between 'Circle 1' or 'Circle 2', and between 'AlongCrv' or 'Crv CP/Sort'. As a wise man once said: "Where there is mystery there is no mastery."

Attachments: