# I need help adding extra rim to a Cylinder!

Referencing the image with the pink cylinder, the end goal is to thicken the webbing at the top of the cylinder (circled in red) to match the webbing at the center of the cylinder (circled in blue).

In grasshopper, I begin with a cylinder with a bottom, create a bounding box around the cylinder, populate the bounding box with points, create a voronoi within the bounding box, then intersect the voronoi with the original cylinder to get some edges. Then, I create points at the intersections of the edges (green crosses in second image) and ultimately create closed faces to create the image with the red transparent faces. Ultimately, I go onto extruding these faces to create the pink solid shown in the bottom image. However, because the top rim of the cylinder has a width of only one face instead of two, the webbing at the top is not as thick as the webbing in the center.

How can I make this webbing at the top thicker??? I feel like I can do something with the green points, but I’m not sure exactly how!

Thanks in advance for the help!

I’ve done this using these steps:

1. Split the top webbing with a horizontal plane positioned about 1/2 way through it’s thickness
2. Use Brep Edges to get the bottom 2 edges from the top portion
3. Use these 2 edges to make a plane surface (Boundary surface)
4. Extrude this surface down by the amount you want to thicken the top web
5. Join this extrusion to the top portion
6. Move #5 up by the same amount of the extrusion and join it to the bottom portion

If you’ve done it properly the result will be a Closed Brep (or valid mesh if that’s what you’ve got,)

If you work with mesh, it would be easy to move only the upper most vertices and reconstruct mesh again…

VoronoiPattern_re.gh (21.6 KB)

And this one produce slightly better result…

VoronoiPattern_reV2.gh (22.1 KB)

Meshes have always seemed like witchcraft to me.

Hi HS_Kim,
Wow, this is great stuff! Did you just create this from scratch yourself? That’s very impressive! The way you constructed things is fascinating. How long have you been working with Grasshopper? I’m still very new to it, just got the software a month ago. Do you have any recommended places to start learning?
Thanks again for the help!
Nate