Hi @fraguada!
A seemingly fundamental geometric issue, that has me perplexed.
The geometry (an uncapped box) was generated by extruding a closed polyline, where gh recognizes all 4 vertices. It then gets interpreted as a single face (untrimmed surface) by the Deconstruct Brep component with only two vertexes and three edges.
Does anyone know what is going on?
Potential_Bug_DeBrepOrExtrude.gh (18.9 KB)
Oh interesting! I’m on 8 SR4…
That’s regression and marked as stop ship. RH-80710
Thanks for reporting.
I think that this is confusing, but in principle not wrong. The extruded polyline extrusion can be converted into a degree 1 nurbs surface (in both directions) which has kinks/creases at each knot value.
What you’re seeing in GH when you DeBrep this, is the degree 1 surface.
When you bake this from GH to Rhino, it results in a 4-face polysurface, unless - and this is where it gets confusing - you switch off CreaseSplitting in Rhino first. Then you get the degree one surface in Rhino too.
This is a regression, the same GH file opened in default Rhino 7 returns 4 surfaces, in default Rhino 8 just 1 (crease splitting is enabled by default in both)
I agree with you, just trying to give some context to the issue.
This was broken when the Extrude component started returning Extrusion geometries instead of Breps.
I’m on 8.10, if i have a extrusion geometry, anyway of exploding it in grasshopper without baking to rhino?
the native extrusion component returns a brep, but some plugins i’m using returns extrusion geomtry instead of a brep
explode.gh (9.3 KB)
If you’re willing to install (or have already installed) the Pufferfish grasshopper add-on, you can use the “Split kinky surface” component from that add-on.
