Intersection points between curves

[ezgi 0]

Hello Everyone,

 

I'm just getting started with marionette and I couldn't find a solution to something that I thought would be just another existing node. Maybe I'm not using the correct search words. I'm not sure. I have been trying to retrieve the intersection points between a curve and a set of lines. Like the line-line segment intersect node does but I couldn't see an easy enough way to do it for 2D curves. Can anyone tell me if I'm overlooking something?

[Marissa Farrell 433]

I'm not positive, but it probably doesn't exist yet.

 

I can look into making one, but it may take me some time. 

It's easy to get line intersections since both objects are linear, but with a curve we'll have to extract the equation for the curve.

 

Is your curve a poly or a NURBS?

[ezgi 0]

Hello Marissa, 

 

Thank you for replying. My curve is a 2D poly in one case and a simple 2D arc in another case that I would have to use the algorithm. I want to extract the intersection points in a list so that I can use them to create a diagonal grid between. I attached the example where I want to intersect lines with an arc for now.

170112_1710_Marionette_Question.vwx

[Marissa Farrell 433]

Here's a file with a node that will intersect lines with circles (arcs are just segments of circles anyhow)

 

I haven't tested in any cases other than the one you've provided, but it's a starting point.

170112_1710_Marionette_Question_MFarrell.vwx

[ezgi 0]

Thank you Marissa! 

 

I hadn't thought of this solution. It works well for both variations that I need. Really appreciated!!!

 

Cheers!

[ccsw 3]

@Marissa Farrell 

 

Hi Marissa I have a similar question,

 

I would like to find the intersection points between nurbs curves as you mentioned above.

 

I am making a gridshell structure using contour nodes to create ribs along a nurbs surface.  I then want to find the intersection of the ribs in order to create pin joints at these locations. I have attached my file.

 

Any help would be appreciated.

gridshell test.vwx

[Marissa Farrell 433]

@ccsw

I've started on this, but hit a bump that I need to spend some more time on.

I'm attaching my progress below.

 

The issue is that there are still some outlying points that I need to find a way to filter out; otherwise, I believe it's performing pretty well. Please let me know if you find any issues.

gridshell test_MFarrell.vwx

[ccsw 3]

@Marissa Farrell

 

That's great thank you! Very useful to see how you did it - I am learning a lot. 

 

Yes, it's working well other than the bounding box - I am looking for a solution too but for now can definitely work with it.

[sbarrett 157]

Here is an option for the issue of the bounding box. I found points along the edges of the surface and created a 2D poly from those points.

 

gridshell test_SBarrett.vwx

[ccsw 3]

@sbarrett  Thanks, works perfectly.