Question:
I would like to realize ‘Project Curve to Surface’ capability using Inventor API. This means the function below. Is it possible to implement using API ?
Solution:
As shown in the UI, there are 3 types of projections:
1. project along a vector:
projects the spline along the normal to the surface. i.e. project each point of the spline to the surface along the normal vector. In UI, the projection of Inventor allows the user to select a direction to project. For 2d curve, the default direction is the normal of the plane the curve locates in. While if you try to project a 3d curve, you must select a direction. Otherwise, the [OK] button is disable.
2. project to the closet point:
finds the closest point of each spline point on the surface.
3. curl to the surface:
forms the projected curve around the curvature of selected face or faces. Note: For Wrap to Surface output, the faces must be a cylinder, cone, or planar. The curves must be planar and tangent to the selected faces
It is easier to implement 1 or 2. For 1, we just need to build the normal and project the point by FindUsingRay. For 2, the method is Face.GetClosestPointTo . The following code asks the the user to select a spline (2d/3d) and a surface. next project and create a 3d spline on the surface.
Private Sub test()
‘ get inventor appliaction
Dim _InvApp As Inventor.Application = Nothing
_InvApp =
System.Runtime.InteropServices.Marshal.
GetActiveObject("Inventor.Application")
Dim oPartDoc As PartDocument
oPartDoc = _InvApp.ActiveDocument
Dim oTG As TransientGeometry
oTG = _InvApp.TransientGeometry
Dim oDef As PartComponentDefinition
oDef = oPartDoc.ComponentDefinition
‘select the spline to project
Dim oObject As Object
oObject =
_InvApp.CommandManager.Pick(
SelectionFilterEnum.kSketch3DCurveFilter,
"Pick a sketch spline")
Dim oSplineToPro As Object
oSplineToPro = oObject
‘select the surface to project to
oObject =
_InvApp.CommandManager.Pick(
SelectionFilterEnum.kPartFaceFilter,
"Pick a surface")
Dim oSurface As Face
oSurface = oObject
‘projection type
Dim oProType As String
oProType = "project along vector"
‘oProType = "project to the closet point"
‘get spline param extents
Dim oEV As CurveEvaluator
oEV = oSplineToPro.Geometry.Evaluator
Dim oMinP As Double
Dim oMaxP As Double
Call oEV.GetParamExtents(oMinP, oMaxP)
‘ number of points we want to project
Dim oNumOfPt As Integer
oNumOfPt = 50
‘the result points of projection
Dim oPointCoords As ObjectCollection
oPointCo
ords =
_InvApp.TransientObjects.
CreateObjectCollection()
‘ select a vector for type 1: "project along vector"
Dim oVectorForProject As UnitVector
oVectorForProject =
oTG.CreateUnitVector()
If oProType = "project along vector" Then
Dim oObjectTemp As Object
oObjectTemp =
_InvApp.CommandManager.Pick(
SelectionFilterEnum.kAllLinearEntities,
"Pick a linear edge")
If Not oObjectTemp Is Nothing Then
Dim oLine As LineSegment
oLine = oObjectTemp.Geometry
oVectorForProject =
oLine.Direction
Else
MsgBox("select a linear edge as" &
"the projection vector!!")
Return
End If
End If
‘ iterate each point and get the projection point
Dim i As Integer
For i = 0 To oNumOfPt
Dim params(0) As Double
params(0) = oMinP + i * (oMaxP – oMinP) / oNumOfPt
Dim points(2) As Double
Call oEV.GetPointAtParam(params, points)
Dim oInvPt As Inventor.Point
oInvPt = oTG.CreatePoint(points(0), points(1), points(2))
‘type 1
If oProType = "project along vector" Then
Dim oFoundEntities As ObjectsEnumerator =
_InvApp.TransientObjects.CreateObjectCollection()
Dim oLocatePtArray As ObjectsEnumerator =
_InvApp.TransientObjects.
CreateObjectCollection()
‘ project each point of the spline to
‘the surface along the normal vector
oDef.FindUsingRay(oInvPt,
oVectorForProject,
0.000000000000001,
oFoundEntities,
oLocatePtArray,
True)
If oLocatePtArray.Count > 0 Then
oPointCoords.Add(
oTG.CreatePoint(oLocatePtArray(1).x,
oLocatePtArray(1).Y,
oLocatePtArray(1).Z))
End If
‘type 2
ElseIf oProType = "project to the closet point" Then
‘finds the closest point of each spline point on the surface.
Dim oClosestPt As Inventor.Point
oClosestPt =
oSurface.GetClosestPointTo(oInvPt)
oPointCoords.Add(
oTG.CreatePoint(oClosestPt.X,
oClosestPt.Y,
oClosestPt.Z))
Else
End If
Next
‘ create the 3d sketch spline with the result points
Dim oNew3dSketch As Sketch3D
oNew3dSketch = oDef.Sketches3D.Add
oNew3dSketch.SketchSplines3D.Add(oPointCoords)
End Sub
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