Work with model from Solidworks, convert to NURBS?

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Permalink Reply by martyn hogg on February 5, 2014 at 2:52pm

From Solid Works you can export as a parasolid or an IGS file and open that in Rhino.

I've used IGS before but I don't know if this is handled as a NURBS surface or not.

I've also saved as STL from Solid Works and imported it into GH as a mesh. This lets you do some analysis with mesh vertices, faces, normals etc.

You might be able to define some NURBS curves or surfaces based on mesh data as long as you don't need to be very accurate.

Permalink Reply by martyn hogg on February 7, 2014 at 10:41am

Can you post a photo of your surface and some more info?

Is the surface flat or curved?

Normally when you datum an object you need a reference plane, line and point on your object which you can align with your world XY Plane, X-axis and origin, for example.

So you need to be able to reference some geometry features on your IGS model and then apply some translations and rotations to datum it at (0,0,0)

Permalink Reply by martyn hogg on February 8, 2014 at 5:18am

I'm on RhinoV4 so I can't really check out your model properly.

It's annoying how Solid Works is set so the Top Plane is not the XY plane... I always have to remember to start on the Front Plane!

I'm not sure exactly how you would do what you are trying to do, but I remember some examples where they take the cell boundaries from Voronoi and offset them inward (or scale about the polygon centre) to create a mesh. This is then thickened using the Weaverbird MeshThicken tool.

Instead of ending up with curves to cut your original surface I would take the polyline voronoi curves from the voronoi intersections with your lampshade surface and use these as the starting point for a mesh that you could thicken and then smoothen with Weaverbird.

It can be tricky getting organic mesh shapes to have precise sections in certain places for fittings etc. You might want to create a mesh from bRep of the fitting that you could use do do a manual mesh boolean operation to join it to your final lampshade shape. I wouldn't worry about the hole in the top as you can just create a mesh cylinder in Rhino at the end and Mesh Split in Rhino.

Weaverbird Mesh Thicken example

Permalink Reply by martyn hogg on February 8, 2014 at 5:52am

I had a play and came up with something that might get you started...

It explains what I was thinking anyway.

I only managed to connect it to half of your IGS surface... it didn't work when I joined the two halves together and I can't open your Rhino file.

My GH file seems to have a warning on the Polyline component but it gives quite a nice mesh based on your (half) IGS surface!

Attachments:

• 140207VoronoiEggMH.gh, 12 KB

Permalink Reply by martyn hogg on February 8, 2014 at 11:38am

Typical! I thought the cylinder might intersect the egg, then in Rhino you could do Mesh >> Mesh Boolean >> Boolean Split and split the egg with the cylinder to leave a hole.

So one thing you could do is play with the voronoi settings until you get an egg that has material where the cylindrical hole needs to be!

That's the kop out solution!

Another thing you could do is instead of passing one value to the scale factor of the voronoi cell, you could pass a series of scale factors... this series could be n scale factors (where n = number of cells) that are all the same apart from one which would correspond to the cell where your cylinder will be. This scale factor should be say 0.01 so you get a very small opening, smaller than the cylinder. You could then do the mesh boolean as above. It's not a very elegant solution and you will have to manually work out which cell the cylinder will fall in by moving the slider!

I've attached my model with this mod... i cant check yours properly because i'm on Rhino4

Your bounding box position is set by the area centroid of your surface. You can move this box along a XYZ vector and use sliders to set the values of X,Y and Z

Attachments:

• 140207VoronoiEggMH.gh, 15 KB