Extracting Mesh Creases

Hi everyone-

I've recently been turned on to a Rhino plug-in called Techdraw, which allows for a sort of hardline drawing of objects: edges, hidden lines, etc. One thing it does is identify creases in an object...so for example, if I have a mesh with loads of faces, it only draws edges that can be seen as a crease in the mesh. What I'd like to do is be able to replicate this process such that I have a series of polylines in GH that I can perform operations on...clearly there's a way to do it - this plug-in does it - I just wonder how, if anyone has any suggestions for how to start. The way I imagine it's done is by analyzing the mesh topology and testing for mesh face normal variances across shared edges...but I don't really know how to go about starting that process...I haven't done too much with mesh operations to know if there's any sort of shortcut in this process. Any ideas?

thanks!

Dave

Attachments:

mesh.bmp, 2.1 MB
mesh techdraw.bmp, 2.1 MB

Replies to This Discussion

Permalink Reply by Javier Wang on February 11, 2011 at 9:21am

Love it. Good to know.

Also, looking forward to have MeshTopology back in Rhinocommon.

Permalink Reply by Pedro de Azambuja Varela on November 30, 2016 at 12:44pm

I was not able to extract creases using David Rutten's script. I can't get it to work in Mac, although I tried copying the source from the text editor to the vb script editor in GH.

I am now trying to use Ivy to get the Graph and get the connected edges. Or could I do it more easily with a custom script? (i prefer Python)