terribly emergency! selecting the outside srf of a complicated surface.

hello everyone, i am now facing a problem, i used kangaroo to generate a complicated surface, and i need to 3d print it, so i only need the shape of the outside boundary, is there a way to delete the inner srf or a way to choose only the outside boundary?

thanks a lot! terribly emergency!

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Permalink Reply by David Rutten on March 3, 2016 at 2:12am

Only thing I can think of is that you drape another surface or mesh over it. You can either use the Rhino _Drape command or shoot a bunch of rays at the shape and construct your outer shell from that (automatic, but probably a lot slower).

Permalink Reply by Han Hsun Hsieh on March 3, 2016 at 2:26am

thanks a lot!

sorry, i dont entirely understand what you mean by "shooting ray", could you explain it more?

thanks a lot!

Permalink Reply by David Rutten on March 3, 2016 at 4:12am

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Permalink Reply by Han Hsun Hsieh on March 3, 2016 at 5:20am

thank you, i think i got the idea,

but somehow i cant get it done,

sorry for bothering you

Permalink Reply by Nik Willmore on March 3, 2016 at 11:59am

I had plenty of time and enthusiasm last night to play with this after learning about rays, but I had no sample to work on. Now I'm terribly busy, concerning your terrible emergency.

Permalink Reply by Nik Willmore on March 3, 2016 at 4:48am

I didn't know a ray would only give *one* impact point and not all of the mesh faces it penetrates!

There's a Mesh From Points plug-in for Rhino, once I have populated the exposed surface with points, I just baked and ran it, and it's lightening fast:

http://www.rhino3d.com/download/Rhino/5.0/meshfrompointsV5x64

For this grooved form, there's always holes in the mesh:

It happens in thin valleys:

I'm not sure what to do with the point cloud to surface it besides marching cubes (Cocoon) then offset inwards to re-match the surface instead of effectively offset it outwards by the metaball radius.

Ball Pivot in Grasshopper (a plug-in?), is not easy to even test. Just keeps locking up, whatever ball size I try.

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