Alpha 8 Release note
Published on June 21, 2025 by Romain Guimbal

Where to start ? Ah yes :

This new alpha version is a huge leap for SP and may be the last or second to last version before 1.0 !

1. .STEP I/O

Importing means having an SP equivalent for each .step primitive and we are getting really close :
  • 3D Primitives : All have an equivalent but at different state : 
    • Bezier, NURBS and Planes surfaces got  I/O improved and more reliable (knot vector and weights preservation...)
    • Torus & Cylinders are importing and exporting
    • Spheres, Cones and Surfaces of revolution import but don't export yet
    • Extrusion surfaces and Offset surfaces, which are the 2 last types a step may contain, are close to import work but couldn't make it in time (Extrusion should sometimes imports...).
  • 2D Primitives : Ellipses and Arcs of Ellipses where the two missing boys. They were more challenging that they seem, especially to have a control geometry which is intuitive to make and edit. But no compromises where made and as a consequence it brought some serious improvement to circles as well as the entire curve system. Note that Arcs of Ellipses are not exporting for them moment.
  • Import Performances : Step files do not rarely contain >100 000 entities which are each converted to a Blender object, which has to be evaluated through GeometryNodes. While it will never match the speed of a standard importer, with multi-threading and a proper control over the process, the work paid. The RAM is no longer filling up and the speed is very decent now.

  • Other importer improvement
    • Handle Compound transforms
    • Import the hierarchy as collections
    • Fix : Segment poles out of parameter range 
  • Other exporter improvement
    • Export with collections as hierarchy (instancing is almost there, it worked for like 2sec)

2. Interpolation and fitting

  • Interpolate curve
  • Fit curve
  • Interpolate Patch
  • Fit patch
  • New parametrization methods  
Interpolation is a key element which will unlock many features. The following are already there :
  • Project Curve on patch
  • Nearest curve on patch
  • NURBS can now export as SVG
Note : Interpolation is what was called "through points" before
 

3. Fundamental forms for continuity analysis

This is the advanced boy. I dived in differential geometry to extract the principal curvatures in evaluated points so now you can now : 
  • Display principal curvatures on patch at intervals : Curvature Analysis modifier
  • Plot Principal curvatures deviation with connected patch : Continuity analysis modifier

4. General & Workflow

  • NURBS should be at least twice as fast and use way less memory
  • DLL not found should... not ha...ppen anymore ? hehe let me know, please
  •  SP now complies with extension platform requirements
  • Pie menu : Shift + F gives access to segment type selection and Endpoints toggle
  • Shift + Alt + F toggles endpoint
  • Thoses functions are also accessible from the add-on's main panel
  • NURBS combs now actually work (weighting was missing)
  • FlatPatch Radial Array
  • Store vertex groups as attributes (Endpoints and Trim Contour can still be both) -> Fixes errors due to apply modifier
  • Delegate 3D edge computation to the connecting patch. It was the on the connected patch before and it was extremely slow to compute and unnecessary, it is no longer.
  • Curve circles can now be oriented with a 3rd point. With only 2 points, it lies on the XY plane.
  • Mirror CP should behave better for CP near the seam.
  • A hundred little adjustments

For the ones really attentive : Compound objects where one of the focus for this release, but although it worked well and got exciting fast, I encountered a serious obstacle for exporting : I need to read attributes of instances. It is probably possible but not made for it complex, so I shifted focus and did not included anything in this release.

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