Get parameters of face at centroid using SOLIDWORKS API

This example demonstrate how to find the parameters (point coordinate and normal) at the center of the face using SOLIDWORKS API. This macro will work with any type of face (planar, cylindrical, toroidal, b-surface etc.)

Center is found as the average of minimum and maximum values of U and V parameters using the ISurface::Evaluate SOLIDWORKS API method.

Dim swApp As SldWorks.SldWorks
Dim swModel As SldWorks.ModelDoc2

Sub main()

    Set swApp = Application.SldWorks
    
    Set swModel = swApp.ActiveDoc
    
    If Not swModel Is Nothing Then
        
        Dim swFace As SldWorks.Face2
        Set swFace = swModel.SelectionManager.GetSelectedObject6(1, -1)
        
        If Not swFace Is Nothing Then
            
            Dim vPt As Variant
            Dim vNorm As Variant
            
            GetFaceCenterParameters swFace, vPt, vNorm
            
            Debug.Print "Coordinate at face center is: " & vPt(0) * 1000 & ", " & vPt(1) * 1000 & ", " & vPt(2) * 1000
            Debug.Print "Normal at face center is: " & vNorm(0) & ", " & vNorm(1) & ", " & vNorm(2)
        
        Else
            MsgBox "Please select face"
        End If
        
    Else
        MsgBox "Please open the model"
    End If
    
End Sub

Sub GetFaceCenterParameters(face As SldWorks.Face2, ByRef point As Variant, ByRef normal As Variant)
    
    Dim vUvBounds As Variant
    vUvBounds = face.GetUVBounds
    
    Dim centerU As Double
    Dim centerV As Double
        
    centerU = (vUvBounds(0) + vUvBounds(1)) / 2
    centerV = (vUvBounds(2) + vUvBounds(3)) / 2
    
    Dim swSurf As SldWorks.Surface
    Set swSurf = face.GetSurface
    
    Dim vEvalRes As Variant
    vEvalRes = swSurf.Evaluate(centerU, centerV, 0, 0)
    
    Dim dPoint(2) As Double
    Dim dNormal(2) As Double
    
    dPoint(0) = vEvalRes(0)
    dPoint(1) = vEvalRes(1)
    dPoint(2) = vEvalRes(2)
    
    dNormal(0) = vEvalRes(3)
    dNormal(1) = vEvalRes(4)
    dNormal(2) = vEvalRes(5)
    
    point = dPoint
    normal = dNormal
    
End Sub