SurfaceCurvature

Returns the curvature of a surface at a U,V parameter. See the Rhino help file for details on surface curvature.

Rhino.SurfaceCurvature (strObject, arrParameter)

strObject	Required. String. The object's identifier.
arrParameter	Required. Array. An array containing the U,V parameter to evaluate.

Array

An array of curvature information if successful. The array will contain the following information:

Element	Type	Description
0	Array (3-D Point)	3-D point at the specified U,V parameter.
1	Array (3-D Vector)	Normal direction (vector).
2	Number	Maximum principal curvature.
3	Array (3-D Vector)	Maximum principal curvature direction (vector).
4	Number	Minimum principal curvature.
5	Array (3-D Vector)	Minimum principal curvature direction (vector).
6	Number	Gaussian curvature.
7	Number	Mean curvature.

Null

If not successful, or on error.

Const rhObjectSurface = 8

Dim strObject, arrPoint, arrParam, arrData

strObject = Rhino.GetObject("Select a surface", rhObjectSurface)

If Rhino.IsSurface(strObject) Then

arrPoint = Rhino.GetPointOnSurface(strObject, "Pick a test point")

if IsArray(arrPoint) Then

arrParam = Rhino.SurfaceClosestPoint(strObject, arrPoint)

If IsArray(arrParam) Then

arrData = Rhino.SurfaceCurvature(strObject, arrParam)

If IsArray(arrData) Then

Rhino.Print "Surface curvature evaluation at parameter (" & CStr(arrParam(0)) & ", " & CStr(arrParam(1)) &"):"

Rhino.Print " 3-D Point: (" & Rhino.Pt2Str(arrData(0)) & ")"

Rhino.Print " 3-D Normal: (" & Rhino.Pt2Str(arrData(1)) & ")"

Rhino.Print " Maximum principal curvature: " & CStr(arrData(2)) & " (" & Rhino.Pt2Str(arrData(3)) & ")"

Rhino.Print " Minimum principal curvature: " & CStr(arrData(4)) & " (" & Rhino.Pt2Str(arrData(5)) & ")"