[SOLVED] Approximate BSpline Surface radius

[brst]

Hello,

I want to get the approximate radius of a BSpline surface. My first thought was unwrapping it. Using the smallest bounding box dimension doesn't work if the flattened face orientation isn't parallel to the coodinate system axis, so one could use the minimum Volume BoundingBox from Mesh.
Is there a better way to aquire the radius?

[wmayer]

What about using the inverse of the minimum and maximum curvature value at a given point?

Code: Select all

s=App.ActiveDocument.ActiveObject.Shape.Face1.Surface
c=s.uIso(0.1)
Part.show(c.toShape())
c.centerOfCurvature(0.5)
c.curvature(0.5)

circle=Part.Circle()
circle.Center=c.centerOfCurvature(0.5)
circle.Radius=1/c.curvature(0.5)

pnt=s.value(0.1,0.5)
Part.show(Part.Vertex(pnt))

sph=Part.Sphere()
sph.Center=circle.Center
sph.Radius=circle.Radius
Part.show(sph.toShape())

[easyw-fc]

you may also have a look at Caliper of Mnaipulator WB
https://forum.freecadweb.org/viewtopic. ... 54#p257476

[wandererfan]

I want to get the approxiamte radius of a BSpline surface. My first thought was unwrapping it. Using the smallest bounding box dimension doesn't work if the flattened face orientation isn't parallel to the coodinate system axis, so one could use the minimum Volume BoundingBox from Mesh.
Is there a better way to aquire the radius?

It's about curves, not surfaces, but there might be some hints here: https://forum.freecadweb.org/viewtopic. ... le+bspline

[chrisb]

In Path workbench a tesselation with arc is performed, because GCodes know only straight lines and arcs. Perhaps you can use something from there.

[brst]

What about using the inverse of the minimum and maximum curvature value at a given point?

Code: Select all

s=App.ActiveDocument.ActiveObject.Shape.Face1.Surface
c=s.uIso(0.1)
Part.show(c.toShape())
c.centerOfCurvature(0.5)
c.curvature(0.5)

circle=Part.Circle()
circle.Center=c.centerOfCurvature(0.5)
circle.Radius=1/c.curvature(0.5)

pnt=s.value(0.1,0.5)
Part.show(Part.Vertex(pnt))

sph=Part.Sphere()
sph.Center=circle.Center
sph.Radius=circle.Radius
Part.show(sph.toShape())

Thanks Werner! That's exactly what i was looking for. I didn't know about uIso.