Extracting Point Set From Face(s)

I'd suggest looking into the UF_MODL_ask_face_props function. Given a U,V point on a face, it will return a point location, first and second derivatives, and radius of curvature of the face. The UF_MODL_ask_face_uv_minmax function can be used in conjunction to set limits as you iterate over the face of interest.




I can try to put together a quick demo journal if you are interested.

Here's some code that will hopefully get you started:





Option Strict Off
Imports System
Imports System.Data
Imports NXOpen
Imports NXOpen.UF

Module points_on_face

Sub Main()

Dim theSession As Session = Session.GetSession()
Dim theUfSession As UFSession = UFSession.GetUFSession()
Dim lw As ListingWindow = theSession.ListingWindow
lw.Open()

Dim theFace As Face
If SelectFace("select a face", theFace) = Selection.Response.Cancel Then
Return
End If

Dim myDocs As String
myDocs = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments)
Dim outputFile As String = IO.Path.Combine(myDocs, "FaceData.csv")

Dim faceTable As New DataTable("Face")
faceTable.Columns.Add("ID", GetType(Integer))
faceTable.Columns.Add("U", GetType(Double))
faceTable.Columns.Add("V", GetType(Double))
faceTable.Columns.Add("X", GetType(Double))
faceTable.Columns.Add("Y", GetType(Double))
faceTable.Columns.Add("Z", GetType(Double))
faceTable.Columns.Add("U1_X", GetType(Double))
faceTable.Columns.Add("U1_Y", GetType(Double))
faceTable.Columns.Add("U1_Z", GetType(Double))
faceTable.Columns.Add("V1_X", GetType(Double))
faceTable.Columns.Add("V1_Y", GetType(Double))
faceTable.Columns.Add("V1_Z", GetType(Double))
faceTable.Columns.Add("U2_X", GetType(Double))
faceTable.Columns.Add("U2_Y", GetType(Double))
faceTable.Columns.Add("U2_Z", GetType(Double))
faceTable.Columns.Add("V2_X", GetType(Double))
faceTable.Columns.Add("V2_Y", GetType(Double))
faceTable.Columns.Add("V2_Z", GetType(Double))
faceTable.Columns.Add("norm_X", GetType(Double))
faceTable.Columns.Add("norm_Y", GetType(Double))
faceTable.Columns.Add("norm_Z", GetType(Double))
faceTable.Columns.Add("radius_U", GetType(Double))
faceTable.Columns.Add("radius_V", GetType(Double))

Dim uvMinMax(3) As Double
theUfSession.Modl.AskFaceUvMinmax(theFace.Tag, uvMinMax)

lw.WriteLine("U min: " & uvMinMax(0).ToString)
lw.WriteLine("U max: " & uvMinMax(1).ToString)
lw.WriteLine("V min: " & uvMinMax(2).ToString)
lw.WriteLine("V max: " & uvMinMax(3).ToString)

Const numPtsU As Integer = 10
Const numPtsV As Integer = 10
Dim stepU As Double = (uvMinMax(1) - uvMinMax(0)) / numPtsU
Dim stepV As Double = (uvMinMax(3) - uvMinMax(2)) / numPtsV

'time variables to record how long the operation took
Dim startTime As DateTime = Now
Dim endTime As DateTime
Dim timeElapsed As TimeSpan

For iu As Integer = 0 To numPtsU
For iv As Integer = 0 To numPtsV
Dim param(1) As Double
param(0) = uvMinMax(0) + iu * stepU
param(1) = uvMinMax(2) + iv * stepV

Dim pt(2) As Double
Dim u1(2) As Double
Dim v1(2) As Double
Dim u2(2) As Double
Dim v2(2) As Double
Dim norm(2) As Double
Dim radii(1) As Double

theUfSession.Modl.AskFaceProps(theFace.Tag, param, pt, u1, v1, u2, v2, norm, radii)
faceTable.Rows.Add(theFace.Tag, param(0), param(1), _
pt(0), pt(1), pt(2), _
u1(0), u1(1), u1(2), _
v1(0), v1(1), v1(2), _
u2(0), u2(1), u2(2), _
v2(0), v2(1), v2(2), _
norm(0), norm(1), norm(2), _
radii(0), radii(1))

Next
Next

endTime = Now
timeElapsed = endTime.Subtract(startTime)
lw.WriteLine("finished collecting surface data")
lw.WriteLine("Time elapsed: " & timeElapsed.ToString)
lw.WriteLine("")

' Create DataView
Dim view As New DataView(faceTable)

'write data to CSV file
Using myWriter As New IO.StreamWriter(outputFile, False)
myWriter.WriteLine("Face Tag, U param, V param, point(X), point(Y), point(Z), U'(X), U'(Y), U'(Z), V'(X), V'(Y), V'(Z), U''(X), U''(Y), U''(Z), V''(X), V''(Y), V''(Z), normal(X), normal(Y), normal(Z), radius(U), radius(V)")
For Each row As DataRowView In view
myWriter.WriteLine(row("ID") & "," & row("U") & "," & row("V") & "," & _
row("X") & "," & row("Y") & "," & row("Z") & "," & _
row("U1_X") & "," & row("U1_Y") & "," & row("U1_Z") & "," & _
row("V1_X") & "," & row("V1_Y") & "," & row("V1_Z") & "," & _
row("U2_X") & "," & row("U2_Y") & "," & row("U2_Z") & "," & _
row("V2_X") & "," & row("V2_Y") & "," & row("V2_Z") & "," & _
row("norm_X") & "," & row("norm_Y") & "," & row("norm_Z") & "," & _
row("radius_U") & "," & row("radius_V"))
Next
End Using

lw.WriteLine("face data written to: " & outputFile)

Diagnostics.Process.Start(outputFile)

End Sub

Function SelectFace(ByVal prompt As String, ByRef selObj As TaggedObject) As Selection.Response

Dim theUI As UI = UI.GetUI
Dim title As String = "Select a face"
Dim includeFeatures As Boolean = False
Dim keepHighlighted As Boolean = False
Dim selAction As Selection.SelectionAction = Selection.SelectionAction.ClearAndEnableSpecific
Dim cursor As Point3d
Dim scope As Selection.SelectionScope = Selection.SelectionScope.WorkPart
Dim selectionMask_array(0) As Selection.MaskTriple

With selectionMask_array(0)
.Type = UFConstants.UF_solid_type
.SolidBodySubtype = UFConstants.UF_UI_SEL_FEATURE_ANY_FACE
End With

Dim resp As Selection.Response = theUI.SelectionManager.SelectTaggedObject(prompt, _
title, scope, selAction, _
includeFeatures, keepHighlighted, selectionMask_array, _
selobj, cursor)
If resp = Selection.Response.ObjectSelected OrElse resp = Selection.Response.ObjectSelectedByName Then
Return Selection.Response.Ok
Else
Return Selection.Response.Cancel
End If

End Function

End Module

If you're new to all this, I recommend that you use VB or C# rather than C++. The .NET API and languages are much easier, which is why so many people use them.