Branching

Hi guys,

I am recently working on a bridge project but stucked by one problem:

As we can see from the attached image, I need to branch one ellipse into two.

But I don't know how to get a smooth transformation between this branching...

Do anybody know how to do it in Grasshopper?

Thanks very much.

Replies to This Discussion

Permalink Reply by David Rutten on November 10, 2011 at 1:47am

Do you know how to do it in Rhino?

Grasshopper doesn't have a surface blend yet, let alone a branching blend. This will be very difficult and possibly even impossible unless you're willing to write the blend algorithm from scratch in C#.

You could give T-Splines a go, it was sort of made for these kinds of problems.

Two more possible solutions would involve meshes. You can try creating a box-like mesh and then use Catmull-Clark smoothing (you'll need to download the Weaverbird plugin for this). The other approach is metaballs. You might be able to treat your branching shape as a series of 2D metaball sections, which will give you a stack of polylines. You'll still need to convert those to a mesh afterwards though.

At any rate it will be very difficult to make the Y-branch attach itself to the naked edges of the existing tubes, and if you want tangency or curvature continuity, that'll be even harder.

David Rutten

david@mcneel.com

Poprad, Slovakia

Permalink Reply by Jack Zeng on November 10, 2011 at 7:13am

Thank you very much David, I am trying to figure out how to use Catmull-Clark smoothing and metaball. A friend show me how to achieve this manually in Rhino:

http://www.rhino3d.com/tutorials/howto/branch/index.htm

However we have a large amount of this branching need to model and as you said, it might not be able to guarantee the tangency or curvature continuity...

I will try Kangaroo mesh relaxation as well. The branching looks smooth but don't know if we can control the section on each end.

Permalink Reply by Milou Teeling on September 15, 2014 at 10:58am