NurbsCurve3D.extract always throws exception

[JesusFreke]

When I try to call the extract method on a NurbsCurve3D object,  I get a RuntimeError with the message "RuntimeError: 3 : invalid argument startParam".

For example:

import adsk.core
import adsk.fusion
import traceback

def run(_):
    try:
        brep = adsk.fusion.TemporaryBRepManager.get()

        cylinder = brep.createCylinderOrCone(
            adsk.core.Point3D.create(0, 0, 0),
            1,
            adsk.core.Point3D.create(0, 0, 1),
            1)

        for face in cylinder.faces:
            if isinstance(face.geometry, adsk.core.Plane):
                nurbs = face.edges[0].geometry.asNurbsCurve
                print(nurbs.evaluator.getParameterExtents())
                extracted = nurbs.extract(1.0, 2.0)
                print(extracted)
    except Exception as ex:
        print(traceback.format_exc())

which results in:

[True, 0.0, 6.283185307179586]
Traceback (most recent call last):
File "[...]\test.py", line 36, in run
extracted = nurbs.extract(1.0, 2.0)
File "[...]/AppData/Local/Autodesk/webdeploy/production/c23c4c7ff2652eaacfec153295bbc3d6e4b9657f/Api/Python/packages\adsk\core.py", line 24329, in extract
return _core.NurbsCurve3D_extract(self, *args)
RuntimeError: 3 : invalid argument startParam

The above exception was the direct cause of the following exception:

SystemError: <built-in function delete_BRepFaces> returned a result with an error set

Seems like a bug in the API? 

[MichaelT_123]

Hi Mr. JesusFreke,

Is it a bug?

Might be not...

Please, consider to follow the schema:

baseFeature.startEdit()

(your tempBody code)

thisBody      = thisComp.bRepBodies.add( tempBody, baseFeature )

baseFeature.finishEdit()

.....

extracted = nurbs.extract(1.0, 2.0) 

Regards

MichaelT

[JesusFreke]

Were you actually able to get that to work? Because I still get the "invalid argument startParam" exception.

import adsk.core
import adsk.fusion
import traceback

def run(_):
    app = adsk.core.Application.get()
    design: adsk.fusion.Design = app.activeProduct

    root: adsk.fusion.Component = design.rootComponent

    brep = adsk.fusion.TemporaryBRepManager.get()

    base_feature = root.features.baseFeatures.add()
    base_feature.startEdit()

    try:
        cylinder = brep.createCylinderOrCone(
            adsk.core.Point3D.create(0, 0, 0),
            1,
            adsk.core.Point3D.create(0, 0, 1),
            1)

        cylinder = root.bRepBodies.add(cylinder, base_feature)

        for face in cylinder.faces:
            if isinstance(face.geometry, adsk.core.Plane):
                nurbs = face.edges[0].geometry.asNurbsCurve
                print(nurbs.evaluator.getParameterExtents())
                extracted = nurbs.extract(1.0, 2.0)
                print(extracted)

    except Exception:
        print(traceback.format_exc())
    finally:
        base_feature.finishEdit()

It also, happens if I finish the base feature before trying to split the spline, and also when the document is in direct mode instead of parametric mode.

[BrianEkins]

It looks like a bug in the API to me.