Grasshopper Extrusion Surfaces

Using GH with rhino 6

I’m trying to create some scripts to automate the process of building a site model. Through this process, I’ve created some generic building components and it seems as though using the extrude grasshopper component is causing some surface issues (that I am not sure how to properly articulate). It is easier to just show the issue with photos:

^Baked Geometry (shaded view showing surface issue)

^Desired Geometry

^Rendered Geometry (phantom surfaces…)

without looking at the script (which I can post if needed), I was wondering if an experienced eye might have come across this weird phantom geometry issue before…

Your time is appreciated.

Hi Cpin,

Did you solve this already?
Without seeing the definition it’s guesswork, but could it be your object is very small and/or very far from the world origin. That could cause issues with floating point precision where display meshes get messy like that.


Hi Willem,

I was importing a CAD file that contained site information. It was downloaded from a competition site, and maybe the CAD file was corrupt (or too dense, or something else).

grasshopper aside, even extruding a box would get corrupt surfaces. So I’m guessing the import screwed the model up in some way.

My work around was just importing the CAD into a rhino file, and then copying the curves I needed from that file (now broken, due to import), into a fresh file. It solved my issue. I guess this isn’t a grasshopper issue at all…


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