VB Get the angle in degree of the Y axis in my current view

[peter.stahl]

Hey guys,

it's a bit complicated to explain WHY - but I need to get the angle of the Y axis in the current view. The picture helps to explain what I need.

 

I have put together a code to turn the screen around the axis that stands vertical on my screendisplay (not the UCS axis!).  

If I would be able to measure how many degree the Y axis in my current view is off, let's say 5°, than I can rotate the view -5° back with my function below.

Do you have any idea how to measure the angle?

Public Sub RotateMe()
    Call RotateAroundDisplayAxis("Z", -5)
End Sub

Public Sub RotateAroundDisplayAxis(ByVal axis As String, ByVal degree As Integer, Optional ByVal CW As Boolean = True)
' collected by PS 2020.10.05
' This example simply rotates the view around an axis of the actual view - not the UCS!

' turning around the axis vertical to the screen from: http://ww3.cad.de/foren/ubb/Forum258/HTML/000587.shtml
' turning around the vertical & horizontal axis of the screen from: https://forums.autodesk.com/t5/inventor-customization/camera-upvector/td-p/757637

    Dim oView As View
    Set oView = ThisApplication.ActiveView
    
    Dim oCamera As camera
    Set oCamera = oView.camera
    
    Select Case axis
    Case "Z"
        Dim uVector As UnitVector
        ox = oCamera.Eye.x - oCamera.Target.x
        oy = oCamera.Eye.y - oCamera.Target.y
        oz = oCamera.Eye.Z - oCamera.Target.Z
        Set oNewUp = ThisApplication.TransientGeometry.CreateUnitVector(ox, oy, oz)
        
        If CW Then 'rotate CW
            oCamera.UpVector = oNewUp.CrossProduct(oCamera.UpVector)
        Else 'rotate CCW
            oCamera.UpVector = oCamera.UpVector.CrossProduct(oNewUp)
        End If
        
    Case "X", "Y"
        Dim FPoint As Point2d 'rotation points
        Dim TPoint As Point2d
        Dim rVal As Double 'rotation values
        Dim yVal As Double
        Dim radV As Double
        radV = Math.Atn(1) / 2.25 'PS: Math.Atn(1) = 45°
        rVal = degree * -radV
        
        If CW Then 'rotate CW
            Select Case axis
            Case "X"
                Set FPoint = ThisApplication.TransientGeometry.CreatePoint2d(0, 0)
                Set TPoint = ThisApplication.TransientGeometry.CreatePoint2d(0, rVal)
            Case "Y"
                Set FPoint = ThisApplication.TransientGeometry.CreatePoint2d(0, 0)
                Set TPoint = ThisApplication.TransientGeometry.CreatePoint2d(rVal, 0)
            End Select
        Else  'rotate CCW
            Select Case axis
            Case "X"
                Set FPoint = ThisApplication.TransientGeometry.CreatePoint2d(0, rVal)
                Set TPoint = ThisApplication.TransientGeometry.CreatePoint2d(0, 0)
            Case "Y"
                Set FPoint = ThisApplication.TransientGeometry.CreatePoint2d(rVal, 0)
                Set TPoint = ThisApplication.TransientGeometry.CreatePoint2d(0, 0)
            End Select
        End If
        
        oCamera.ComputeWithMouseInput FPoint, TPoint, 0, kRotateViewOperation
    End Select
    
    oCamera.Apply
    oCamera.Fit
End Sub

[_dscholtes_]

If you only want to rotate the screen such that the Y-axis is aligned vertical (and points up), I would store the direction of the Y-axis in a vector and set it as the UpVector of the camera object. After that, just Apply the new settings (without need for any calculations)

1. The direction of the Y-axis can be obtain with something like:
   oVectorY = <your open file>.ComponentDefinition.WorkAxes(2).Line.Direction.AsVector
2. You have to convert it to a UnitVector, like:
   oVectorUp = oVectorY.AsUnitVector
3. Set it to the camera object:
   oCamera.UpVector = oVectorUp
4. And apply settings:
   oCamera.Apply

If you do want to calculate the angle, I'd try the following:

1. Get the UpVector of the camera and store it as a vector (oVector1);
2. Store the direction of the Y-axis as a vector (oVector2);
3. Calculate the angle between them using: dAngle = oVector1.AngleTo(oVector2), where dAngle is a double.
   (I don't know which angle between the vectors is returned, the large or the small one)