Normal projection of a curve onto a BRep

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Permalink Reply by Lorenzo Gambino on November 20, 2009 at 11:21am

Hi
Maybe you already solved the problem since you post this but I downloaded your files and had a look...If I understanded right you're trying to create repeated identical curves on a path..
take a look to this discussion..there I think we solved the problem ;)

http://www.grasshopper3d.com/forum/topics/repeating-a-curve

You can use the repeated curves as sweep rails.
Hope to be helpful.
bye

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Permalink Reply by Juan Estevez on November 23, 2009 at 3:16pm

I will take a look, thanks!!

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Permalink Reply by Des Igner on February 13, 2011 at 10:59pm

Hi all,

I too would like to use the "Extrude curve Normal to surface" as in Rhino for GH. Is there any other discussion on this topic or can anyone else please help?

I need to construct vertical and horizontal support webs (normal to the surface, not parrallel to each other) of a constant width.

 

Similar to the attached rhino doc.

 

Des

 

Attachments:

• create Surface by Extrude curve Normal to Surface.3dm, 382 KB

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Permalink Reply by Andrew Heumann on February 14, 2011 at 2:06am

Attached is a definition that reproduces the "fin" or "extrude crv normal to srf" command in rhino. 

Attachments:

• Fin.ghx, 110 KB

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Permalink Reply by Des Igner on February 14, 2011 at 11:40pm

Hi Andrew,

That looks great! Many thanks for your help. I'm new to GH and will need time to understand each part. I am interested where you got the curve data in the curve paramater at your start?

I previously started with the example by Zubin (p153 fabrication) attached, as it is handy to have sliders for the curves but your method appears simpler.

Regards

Des

Attachments:

• Fin2.ghx, 260 KB

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Permalink Reply by Gabe Krause on February 15, 2011 at 12:09pm

The way you have extruded the curve from the surface works along the normals, which is probably good for Des; But, the way you've projected the original curve to the original surface doesn't quite follow the surface normals. Check it with Rhino's "Pull Curve to Surface" command.

Admittedly, Juan's original question in the post isn't clear to me. But inferring from the post's title, I think an accurate normal projection is what was originally asked for. The attached definition will provide an accurate projection of a curve to a surface via the surface's normals.

From there one could use various methods to extrude or loft along the surface normals.

Attachments:

• ProjNorm.3dm, 66 KB
• ProjNorm.ghx, 137 KB

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