I have a complex surface, and I wanna find its tangent surface, which is linear along Z-axis.
I tryed make2d and than extruded the projection curve,like p2. It seems the correct surface, but it can’t have an intersecting curve from the base surface, due to the accuracy issue, so I can’t find where the tangent surface exactly ends.
Then I thought I can extract all isocurve, and find closest point on these U isocurve from an inner reference surface, and interpolate them on the base surface. But hey, I still have no easy one-command-method to solve this, and “dividing curve then surface CP” leads to more deviation.
so how can I find a accurate tangent surface? Modeling andGrasshopper methods are all welcomed!
English is not my first language, but I still hope that I could be understood.
Hi @polykuma
You’re not gonna find a clean and simple tangent section on a surface this complex. The distribution of control points and the curvature is all over the place. A couple of notes:
a) Your surface is +400 meters away from W0, which will almost certainly (or at least probably) cause trouble when working in mm.
b) If you turn on curvature analysis or curvature graph, you will see that the surface has some really uneven changes in curvature, causing the tangent to be less than optimal.
c) To get an approximation of the tangent, you can use either Silhouette in the top view or create the mid draft curve using the DraftAngleAnalysis tool. Note that both these tools rely on the analysis mesh, so crank up the settings to get a better result.
d) If you rebuild and connect the resulting curves (I did 300 points, degree 3), you can then Pull that curve to the surface and get a surface that is tangent within 0.01°. But it ain’t exactly pretty.
Thanks a lot, @Jakob!
It’s my bad. I just copy it out of my project without setting a proper working plane here. DraftAngleAnalysis is what exactly I need.
THX again !
What works rather well is to use DeepL, type your text in your language, and paste the English translation. That’s how I use French and Spanish electronics fora as a non-native speaker.
It’s not quite a hard thing for me to use English here. I’m just afaid I can’t translate technical terms well and cause misunderstanding. I tried Google and DeepL, and I think LLM does better in this case. But hey thanks again, still inspiring.
