Radius of curvature

Geometry
1

Hi everyone,
I am getting stuck for finding a solution to determine the radius of culvature on a curve located in 3D coordinate system, which helps me to check the radius of any point in a 3D curve.
I know in Rhino 3D or in AutoCAD I can check it freely. But in Revit, there is no such function like that.

RCulvature
RCulvature877×673 109 KB

2

If you have this curve in AutoCAD file link it to Revit and use bimorph package to get the geometry of it.

3

@ingenieroahmad Hi, I have BimorphNodes package, but I don’t see any nodes for the purpose checking the radius of curvature.

4

when you get the geometry you can deconstruct the polycurve to curves and get the required redius.

1 Like
5

It’s a good idea but not enough for me haha.
Look at the photo below. I used the node Curve.ApproximateWithArcAndLineSegments and received almost lines instead of arc. With lines, I can’t define the radius. Sometimes, I have a nurbscurve extremely smooth which deconstructing it only give me lines.

RCulvature_02
RCulvature_021119×803 115 KB

6

The diagram you posted indicates the solution.

Take a sampling of three points on any section of the curve. Draw an arch through the 3 points, and pull that radius.

Some loose design script on my phone which can serve as your guide (likely a typo in there - you can map to nodes or try editing as needed):

crv = nurbsCurve;
n = distanceOfRadiusSample;
o = offsetDistance;
pnts = Curve.PointAtSegmentLength(crv,[n-o,n,n+o]);
targetArc = Arc.ByBestFitThroughPoints(pnts);
sampledRadius = targetArc.Radius;
7

I feel myself so silly by keep paying attention in the math function than having a look at the geometry.
Thank you for the hint.

1 Like