i am trying to remove a column of points between two surfaces that form a gherkin like volume. i don’t know why but when i build this gherkin like volume in rhino or grasshopper using revolve or loft, i get this strange column in the brep or mesh between the inside and outside surfaces.
in the attached script, i have tried to use similarity operator to create a list of X and Y values that are similar - the thinking being that the column of points between these surfaces i am trying to remove would have similar X and Y proximity values - and then cull them out and rebuild the mesh but I can’t get this to work. I’m ultimately trying to create a noise on mesh to deform the overall volume but this column of points eludes me. any thoughts, advice or strategies on this would be kindly appreciated !
Can you provide an example without plugins, please. Not all of us have (or want to have) plugins installed, just for answering a question. (unless of course it is a question about a plugin).
Regards Eef
Thanks for the feedback, I’ve removed components that require these plugins. In doing so, I realised that it was the putterfish offset that was the cause of the problem: when I offset a surface with it and choose the closed option, the brep generated has a small column at the top between the inner and outer surfaces! However, when I modeled it using just the native grasshopper offset, that column did not appear. Weird, I guess it’s a shortcoming of either my modeling technique or putterfish offset.
i have uploaded a revision of this showing both cases, the native offset which works and the putterfish offset which does not work so you can see the difference. fwiw, I would still like to know how to remove that ‘column of points between the inner and outer gherkin surfaces. I’m trying to learn more about list management and culling and i’d appreicate any insights thanks.
I have been struggling a bit. Could not understand why this brep was not closing.
Then understood that the problem was caused when offsetting. It was missing about 0.0000009 from the axis, causing a hole in the revolution.
So I went back to how I would build this:
start with your curve.
offset into 2 directions.
connect the curves to eachother + connect to axis!
Nice solution, amazing analysis to find that tiny distance from the axis causing a hole in the revolution! True, meshes are the last resort in topologies I use for mechanical analysis, fabrication, rendering and patterning in gh - always best to focus on surface builds before them. This surface/brep modeling detail helps prepare them better for that, thank you!
