Auto NURBS Surfacing Of Meshes

The Holy Grail of NURBS design is conversion of easily manipulated and often Grasshopper created meshes into smooth and efficient polysurfaces instead of huge yet still ridiculously sharp-faceted polysurfaces. Geomagic Freeform Pro will do this for tens of thousands of dollars.

I have achieved this goal in Grasshopper by creating both a very fine re-mesh using Kangaroo MeshMachine also a crude yet curvature adaptive re-meshing that I take the *dual* of to afford mostly hexagons/pentagons whose outlines I then project onto the fine mesh, and I also use some random points inside each face to create several tiny little surface normal circles upon the mesh. This lets me use a short Python script to create patch surfaces using parallel processing that is 4X as fast on my four core CPU.

I also included a little Python script to access a brep join command that accepts tolerance so you don't have to tweak the main Rhino tolerance setting to get it to work.

When I updated my Python for Rhino 6 WIP, my Python patch script now crashes in Rhino 5, which is why I'm using Rhino 6 WIP and Grasshopper 1 but it should open in Grasshopper 0.9.X in Rhino 5. I'm not sure if a normal Rhino 5 Python set up will crash too much for other users with this script.

Replies to This Discussion

Permalink Reply by Nik Willmore on April 9, 2016 at 7:41am

I'm using my gallery page as an index rather than a blog format. I usually miss new blog entries since they don't appear in the discussions listings, only at the bottom of the home page. If I want everyday readers, I don't want to be lost in the obscure blog system here. By posting lots of images with so many keywords in my text, I also already dominate Google Images searches for much of geometric inquiry.

Using the forum system here as a personal notebook is actually quite necessary in order to let me remember later what tools I've created and what the limitations and quirks are of them, whereas a bunch of old files on my computer will only get dusty and have disorganized if any documentation.

Permalink Reply by Nik Willmore on May 16, 2016 at 2:16am

Precedent is David Piker's Diagonalize:

http://www.grasshopper3d.com/group/kangaroo/forum/topics/new-exampl...

Permalink Reply by mark zirinsky on April 10, 2016 at 7:49am

great work Nik

Permalink Reply by Nik Willmore on April 12, 2016 at 8:46am

This is a highly simplified version of quad mesh conversion only needing the Kangaroo 1 plug-in, that uses Python to output lines only, lines T-Splines can still convert to a smooth NURBS polysurface. Use the Weaverbird Mesh From Lines (Weave Back) component if you desire a quad mesh in Grasshopper.

Attachments:

Autosurfacing Of Meshes L PYTHON SCRIPT VERSION.gh, 102 KB

Permalink Reply by Nerip on July 4, 2016 at 4:31am

thanks for sharing, very useful research!

Permalink Reply by Jaeyoon Jeong on July 4, 2017 at 4:01am

I got a following result when I tried it. Can you guess what is wrong?

Permalink Reply by Jaeyoon Jeong on July 4, 2017 at 7:21am

I dived into python code of auto-surface grasshopper module, I found that CreatePatch failed sometimes. Do I have to change input params like Spans, Flexibility, Tolerance or etc?

Permalink Reply by Jaeyoon Jeong on July 4, 2017 at 9:42am

I finally found that the problem came from Rhino 6 patch command's bug.

When I convert it to v5 grasshopper, then there was no problem. but it took a little bit long time as it cannot use parallel feature of WIP version, longer than 1 minutes.

I attached grasshopper file for V5 users.

Thanks.

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