Unroller splits up curves?

Rhino Developer
1

I’m trying to use the Unroller class to unroll a few curves and it seems like the unroller splits up 1 of the curves in 2 pieces after unrolling. Joining them afterwards works fine so they are within tolerance of each other. Is there something I’m overseeing or does this just happen sometimes?

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image285×640 2.92 KB

The code I’m using to go from the black to the green line:

Unroller unroll = new Unroller(brepToUseForEnrolling);
unroll.AddFollowingGeometry(curvesToUnroll);
unroll.AbsoluteTolerance = doc.ModelAbsoluteTolerance;
unroll.PerformUnroll(out Curve[] unrolledcurves, out Point3d[] unrolledpoints, out TextDot[] unrolleddots);

I tried both with setting the AbsoluteTolerance and without setting that to the modelabsolutetolerance.

And if this is just the way the unroller sometimes work: if I try to join the list of curves, will it mess up the order of the list?

2

Hi @siemen,

Obviously, we’ll need a sample file before we can answer your question.

Thanks,

– Dale

3

201106 Unroller.3dm (34.6 KB)

´´´

        var go = new GetObject();
        go.GeometryFilter = ObjectType.Surface;
        go.SetCommandPrompt("Select Surface to unroll");

        while (true)
        {
            go.Get();

            if (go.CommandResult() != Result.Success)
                return Result.Failure;

            break;
        }

        Brep unroller = go.Object(0).Brep();

        var gc = new GetObject();
        gc.GeometryFilter = ObjectType.Curve;
        gc.SetCommandPrompt("Select curve to unroll");

        gc.Get();

        Curve CurveToUnroll = gc.Object(0).Curve();

        Unroller unroll = new Unroller(unroller);
        unroll.AddFollowingGeometry(CurveToUnroll);
        unroll.AbsoluteTolerance = doc.ModelAbsoluteTolerance;
        Brep[] breps = unroll.PerformUnroll(out Curve[] unrolledcurves, out Point3d[] unrolledpoints, out TextDot[] unrolleddots);

        foreach (var curve in unrolledcurves)
        {
            doc.Objects.AddCurve(curve);
        }

´´´

4

Any idea what the problem could be @dale? I understand that the curve could potentially split where the curve overlaps the edge of the surface, but it seems like that’s not the case here, since I can join the 2 curves afterwards to a single curve again.

5

Hi @siemen,

I see the UnrollSrf command does the same. I am not sure why. But I’ll file an issue the a developer can review this behavior.

https://mcneel.myjetbrains.com/youtrack/issue/RH-61413

Thanks,

– Dale