"parametric" curve start

Replies to This Discussion

Permalink Reply by Benjamin Golder on October 27, 2009 at 5:01am

Good question. It's the "adjust curve seam" command in rhino, but I'm not sure how to do that in Grasshopper. You can certainly control where the divide curve component starts dividing.

This makes me wonder if you can divide a curve into a series of subintervals. I had a need to do this a while ago, but I found a different solution to my dilemma.

To start the curve divisions in different locations, you would use an evaluate curve component instead of divide curve. you might want to reparameterize the curve, to amke things simpler. then you would simply use a range component to output a series of numbers between 0 and 1 (or if you don't reparameterize, then between the start and end numbers of your curve's interval, which can be obtained with a decompose interval component). Take your list of numbers between 0 and 1, then use the "shift list" component, making sure to wrap the index to the list bounds. The shifted list of numbers that you use could be input into the evaluate curve component, where the "t" is.

Permalink Reply by Benjamin Golder on October 27, 2009 at 5:02am

or even simpler, just shift the list of parameter values coming out of a divide curve component, and then put that shifted list into an evaluate curve component.

Permalink Reply by Pep Tornabell on October 27, 2009 at 5:10am

Correct me if I'm understanding it wrong. That solution would change the start point of the curve to one of the divisions created by the divide curve component. But what I wanted (need) is to adjust .... mmm I thing I get you now. I can rebuild the curve starting at any divison created from the original curve, depending on the division level... I got more accuracy.

Thanks

Permalink Reply by Benjamin Golder on October 27, 2009 at 5:12am

Also, I realized that it would be best if it were smooth, not based on shifting a list. This is a much better solution. Notice that I "reparameterized' the curve on it's way into the evaluate curve component.

Attachments:

• Adjustable_Divide_Curve.ghx, 202 KB

Permalink Reply by Benjamin Golder on October 27, 2009 at 5:13am

I suppose you could use this with an interpolated curve component to rebuild your curve, but that would be an awkward and heavy solution to adjusting the seam.

Permalink Reply by Pep Tornabell on October 27, 2009 at 5:20am

Really nice, thanks.

just for curiosity... why didn't you draw a curve in rhino? The way you created the control points and that seems complicated, compared to the "build " rhino.curve

Anyway, thanks a lot!

Permalink Reply by Benjamin Golder on October 27, 2009 at 9:17am

I just didn't want to have to attach two files. It was pretty easy to pull out and copy the components for the control points.

Permalink Reply by Luis Fraguada on October 27, 2009 at 2:31pm

Are you looking for something like this? Might suffer from some limitations down the line depending what you need it for, but its an idea...
luis