When I run the Intersect command to generate a curve from the polysurface and the planar rectangle surface, I get a curve that crosses itself at this particular plane/surface location:
When I zoom in and inspect the object, things look fine.
Could this issue be related to how the Nurbs object is generated from the conversions?
I should have included that in my topic entry: Iâve been tweaking that setting along with the Mesh options (setting it to custom, increasing density).
The incomplete intersection seems to work better now however unfortunately I still get the self-intersections.
At .0001, there are no self intrersections in the curves here when intersecting the plane and the polysurface - is this correct: sculptureslicing_Curves.3dm (97.9 KB)
?
These intersections are results from using brep-vs-brep as opposed to brep-vs-plane because planes for some reason yielded more inconsistencies.
So yeah who knows, sorry for bothering you with this - I think Iâve done it before when dealing with Rhino WIP (I was originally working on this file using RH8 and went back to 7 because of intersecting bugs).
Eventually I have to resort to work-arounds like producing all parts as curves and not rendering surfaces - which is fine, CNCs need CAD anyway - but a rendering looks nice and helps guide fabrication - you can always manually tweak a profile here and there - however the inconsistency and unpredictability (despite how meticulous one is to keep mesh-to-subd-to-nurb fidelity and cleanliness) are the perplexing element.
It varies - we do laser scanning and mesh things - but not for this purposes as it requires too much clean-up. Fort this case/project, things are manually 3D sculpted, then turned into SubD, either through Rhino or Fusion360 (T-Splines), then breps.
You have a point - however the {other, lol} point is:
Mesh contours/intersections are true to the mesh, meaning curves are actually polylines, which would require rebuilding the contours as you suggest to make them smooth splines - nonetheless rebuilding produces a new approximated curve, which (for obsessive people like us haha) is not accepted as this spline is no longer the actual intersection - hence we choose a specific level of quad mesh resolution prior to SubD generation knowing the nurbs resulting from this conversion ultimately yields intersections that are splines naturally and need no rebuilding - satisfying our desire to obtain the âauthenticâ intersection.
My guess is the problem arises because the intersection just grazes a surface edge - passes within .001. Just the lower of the two faces there at the goofy intersection curve fails to find an intersection at all at .001 but gets the right answer at .0001. Anyway, Iâll get the example on the pile for the developer.
RH-71915 Surface Surface intersection - incorrect result
