Grasshopper

algorithmic modeling for Rhino

# Connecting Points Along Curved Surface

Hello,

I'm trying to connect the points shown on the ellipsoid surface with 2pt segments to create a more faceted surface instead of with curves along the surface (I'm able to pipe the curves but am looking to create 2pt lines I can then offset and extrude normal to the surface).

Is there a way I can do this so that each cell maintains it's own closed curve once the points are connected?

Thanks!

Views: 2865

Attachments:

### Replies to This Discussion

Hi. I'm not sure I understood correctly the part about keeping a closed curve once the points are connected. If all you want is to create extrusions from the line segments, then see the file attached. If what you want is to make a faceted egg, then you need to take another approach (maybe a stretched faceted dome - i included an example), since the polygons aren't planar.

Attachments:

Hello Javier,

Thank you very much for your help on this, you've introduced some ideas I hadn't thought of and a different approach that is interesting. Using your idea I was able to create a faceted voronoi frame, but my intent is to 3D print the model (export as .stl) and there are holes at the points where the pipes meet. I've tried a few things to get this model "air-tight" (eliminate the gaps in the geometry and create a closed surface) so that it can be printed but this is where I'm stumped (see files). Any ideas?

Attachments:

Just create spheres centered at each node.

Spheres radius could be just a little bit bigger than pipes radius, and you should get an easy boolean.

I'll give that a shot, seems like it should work. Adding some complexity, I'm trying to offset each voronoi cell (to be smaller) and then translate each of those offset curves along a vector normal to the centroid point within each cell away from the base surface (see image).

The ultimate aim is to move the offset curves away from the base surface along the vector normal to that cell's centroid, then loft each base cell curve and the offset curve to create something of a barnacle or cone shape open at the end. I've attached the concept image I created showing the idea on a flat surface to give you an idea. I'm trying to essentially recreate this type of geometry over a curved surface using a voronoi pattern instead of hexagonal cells.

Attachments:

Is there a way of isolating the offset curves mentioned above so that the offset distance can be unique to each cell (e.g. each cell offset length could be dictated by the centroid's distance from an attractor point)?

You should make the offset at first with a distance calculated from the function you want.

f(x)=Offset distance

Where x is the distance from each cell center to attractor.

Here a stupid example with a simple remap: (not a real function)

Edit: you did say "cell offset length" , were you talking about something like this? XP

Attachments:

Yes that's part of what I'm after. The other, more difficult part, is being able to then pull those offset curves as a closed single curve away from the base surface along a vector normal to the centroid point inside each cell, each with a variable distance (using an attractor or other influence variable). So if you could imagine what you've shown above, the offset curves (creating a closed curve) inside each cell would then be moved in the z-direction away from the surface some variable distance to create an aperture (see jpeg attached in post above with the honeycomb pattern and cones).

Thoughts?

Another generic example here.

I've used different method for the voronoi cells...

Offset component is a cluster I did using Andrew Heumann's C# code (here: http://www.grasshopper3d.com/forum/topics/offset-problems )

Attachments:

Ah very cool! Thanks a bunch.

I was able to move offset curves away from the dome in the z-direction from each cell plane. Now I'm having trouble trying to loft the base curve and the offset curve to create cone shapes on each cell. Does this require breaking down the geometry into lists or is there a simpler way? If you open the file, the curves I'm interested in lofting are shown in pink and labeled "Cone Base" and "Cone Top" in the gh file.

Attachments:

• View All