Please tell me the way to extract the tangent vector from the point on the circle.

Replies to This Discussion

Permalink Reply by Vongsawat Wongkijjalerd on February 8, 2017 at 9:48pm

So I had some trouble trying to parse/understand the methodology you were using.. so here's a simpler version written from scratch :P

Explanations:
- intersecting the mesh directly as opposed to each face separately will cut back on the tree complexity
- [MeshCP] turns the intersection point in to a mesh parameter (like UV for surfaces)
- [MEval] takes the parameter and outputs the normal at that point
- currently the final output tree structure looks kinda like {0;2circles;270instances}(N=2normals)
- if you put the [Flip] (light blue group) in-between [Cir] and [MCX], it changes it to {0;270instances;2circles}(N=2normals)

The same kind of logic can also be done for surfaces ([SCP] to extract UV, and [EvalSrf] to extract normals) but as each face would be a separate surface you'd need to juggle the tree structure a bit to make sure it works correctly, [Trim Tree] at the end to get rid of all the empty branches etc.

hope that helps.

Edit: an alternate method if you want it organized 'per face': offset inwards all the faces, explode said curve, find midpoint, MCP with mesh, MEval for normals.

Attachments:

• 01v.ghx, 547 KB

Permalink Reply by Kazuhiro Nishimura on February 13, 2017 at 12:45am

It was very helpful.
I would like to try it.
Thank you very much Vongsawat Wongkijjalerd.