TransformBy Example [ActiveX and VBA Reference: AAR]

TransformBy Example

Sub Example_TransformBy()
    ' This example creates a line and rotates it 90 degrees
    ' using a transformation matrix.
    
    ' Create a line
    Dim lineObj As AcadLine
    Dim startPt(0 To 2) As Double
    Dim endPt(0 To 2) As Double
    startPt(0) = 2: startPt(1) = 1: startPt(2) = 0
    endPt(0) = 5: endPt(1) = 1: endPt(2) = 0
    Set lineObj = ThisDrawing.ModelSpace.AddLine(startPt, endPt)
    lineObj.Update
    
    ' Initialize the transMat variable with a transformation matrix
    ' that will rotate an object by 90 degrees about the point(0,0,0)
    ' (More examples of transformation matrices are listed below)
    Dim transMat(0 To 3, 0 To 3) As Double
    transMat(0, 0) = 0#: transMat(0, 1) = -1#: transMat(0, 2) = 0#: transMat(0, 3) = 0#
    transMat(1, 0) = 1#: transMat(1, 1) = 0#: transMat(1, 2) = 0#: transMat(1, 3) = 0#
    transMat(2, 0) = 0#: transMat(2, 1) = 0#: transMat(2, 2) = 1#: transMat(2, 3) = 0#
    transMat(3, 0) = 0#: transMat(3, 1) = 0#: transMat(3, 2) = 0#: transMat(3, 3) = 1#
    
    ' Transform the line using the defined transformation matrix
    MsgBox "Transform the line.", , "TransformBy Example"
    lineObj.TransformBy (transMat)
    ZoomAll
    MsgBox "The line is transformed.", , "TransformBy Example"
    

' More examples of transformation matrices:

' Rotation Matrix: 90 Degrees about point 0,0,0
        ' 0.000000  -1.000000  0.000000  0.000000
        ' 1.000000  0.000000  0.000000  0.000000
        ' 0.000000  0.000000  1.000000  0.000000
        ' 0.000000  0.000000  0.000000  1.000000
        

' Rotation Matrix: 45 Degrees about point 5,5,0
        ' 0.707107  -0.707107  0.000000  5.000000
        ' 0.707107  0.707107  0.000000  -2.071068
        ' 0.000000  0.000000  1.000000  0.000000
        ' 0.000000  0.000000  0.000000  1.000000
        

' Translation Matrix: move an object by 10,10,0
        ' 1.000000  0.000000  0.000000  10.000000
        ' 0.000000  1.000000  0.000000  10.000000
        ' 0.000000  0.000000  1.000000  0.000000
        ' 0.000000  0.000000  0.000000  1.000000

' Scaling Matrix: scale by 10,10 at point 0,0,0
        ' 10.000000  0.000000  0.000000  0.000000
        ' 0.000000  10.000000  0.000000  0.000000
        ' 0.000000  0.000000  10.000000  0.000000
        ' 0.000000  0.000000  0.000000  1.000000
        

' Scaling Matrix: scale by 10 at point 2,2
        ' 10.000000  0.000000  0.000000  -18.000000
        ' 0.000000  10.000000  0.000000  -18.000000
        ' 0.000000  0.000000  10.000000  0.000000
        ' 0.000000  0.000000  0.000000  1.000000
End Sub