How to create polygonal surface with vb?

Hi, I'm looking for a way to create a surface with a vb component, using 6 points (hexagon).

I've found a way to draw a polyline through these points (from this discussion: http://www.grasshopper3d.com/forum/topics/creating-polygons-with-vb...)

But I would also like to fill it with a surface.

However, I've only found a way to create surfaces with a maximum of 4 points (RhUtil.RhinoCreateSurfaceFromCorners(point1, point2, point3, point4)).

Could anyone help me in the right direction?

Thanks!

Fernando

Replies to This Discussion

Permalink Reply by David Rutten on May 7, 2012 at 10:53pm

Hi Fernando,

it is technically possible to create a single hexagonal Nurbs surface, but it involves interior multiple knots, which is generally a bad idea. You're probably better off creating a Trimmed surface, which means you need to create a Brep. If your hexagon is flat you can use the Brep.CreatePlanarBreps Shared method, which does the same as the Rhino PlanarSrf command.

David Rutten

david@mcneel.com

Poprad, Slovakia

Permalink Reply by Fernando Conti on May 8, 2012 at 1:12am

Hi David, thank you for the feedback.

Unfortunately the hexagon needs to follow an organic surface and stretches in all directions.

I tried to find the CreatePlanarBreps method, but I think I'm working with a different namespace (rma.opennurbs)?

Is it still possible to create a surface (non-planar) between the hexagon points? In the end each hexagon-element has to be printed in 3D and then assembled.

Apart from that I'm also struggling to find a VB way to do a boolean subtract from that surface. Each hexagon should have a hole in the center.

Any help is greatly appreciated!
Fernando

Permalink Reply by David Rutten on May 8, 2012 at 1:21am

Hi Fernando,

RMA.OpenNurbs and RMA.Rhino is the old SDK. The new VB/C# components use RhinoCommon (as does Grasshopper natively for quite some time now). I highly recommend using RhinoCommon as it's being actively developed. It's also quite a lot easier to use in my opinion.

Since your 6 corner-points are not co-planar there is no longer a single obvious way to create a surface that intersects them all. You're going to need to tell us how you want the surface to behave in between the points.

David Rutten

david@mcneel.com

Poprad, Slovakia

Permalink Reply by Fernando Conti on May 8, 2012 at 2:44am

Hi David,

I have quickly ported everything to Rhinocommon as you advised. I was not aware of this and worked with older components apparently.

The first thing I miss is the 'RhUtil.RhinoCreateSurfaceFromCorners' method with which I can created four-corner surfaces. Is there another function for this in Rhinocommon?

About the behaviour of the surface in between the points: it just should be as planar/flat as possible, but it's okay if the eventual surfaces have a curvy surface.

Thanks,

Fernando

* EDIT *

I already found the NurbsSurface.CreateFromCorners() method. Rhinocommon is really much clearer.

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