Hi Luigi,
There is no direct way to retrieve this information from the API, however concerning BlockReferences you could use the "BlockReference.BlockTransform" property that returns a 3d matrix and compute those angles (called Euler angles) yourself.
An example of such a computation is illustrated by the code below. Unfortunately it applies to Inventor, but you will be able to invoke equivalent methods from the ARX.Net API on the Matrix3d object.
Concerning Solid3d, this class doesn't expose a transformation property or equivalent information, so unless you created the solid aligned with (X,Y,Z) axis and keep track of any transformation that is applied to it (by keeping a total transformation matrix up-to-date each time the solid is transformed), you won't be able to determine anything about its orientation in space.
Here is the Inventor solution to retrieve the matrix angles:
If we look at the properties of a part in an assembly, we can see the x,y,z coordinates and angles. How can we get the angle values via API?
Solution
There is no direct way to get these angles via API. However, it should be possible to get them via the 4x4 homogeneous transformation matrix.
t11 t12 t13 tx
t21 t22 t23 ty
t31 t32 t33 tz
0 0 0 1
tx, ty, and tz represent the translations along x, y, and z directions.
From the values of other elements of the matrix, one can get the Eulerian/ Cardanian angles.
Public Function Acos(value) As Double
Acos = Math.Atn(-value / Math.Sqr(-value * value + 1)) + 2 * Math.Atn(1)
End Function
Sub CalculateRotationAngles(ByVal oMatrix As Inventor.Matrix, ByRef aRotAngles() As Double)
Const PI = 3.14159265358979
Const TODEGREES As Double = 180 / PI
Dim dB As Double
Dim dC As Double
Dim dNumer As Double
Dim dDenom As Double
Dim dAcosValue As Double
Dim oRotate As Inventor.Matrix
Dim oAxis As Inventor.Vector
Dim oCenter As Inventor.Point
Set oRotate = ThisApplication.TransientGeometry.CreateMatrix
Set oAxis = ThisApplication.TransientGeometry.CreateVector
Set oCenter = ThisApplication.TransientGeometry.CreatePoint
oCenter.X = 0
oCenter.Y = 0
oCenter.Z = 0
'
' Choose aRotAngles[0] about x which transforms axes[2] onto the x-z plane
'
dB = oMatrix.Cell(2, 3)
dC = oMatrix.Cell(3, 3)
dNumer = dC
dDenom = Sqr(dB * dB + dC * dC)
' Make sure we can do the division. If not, then axes[2] is already in the x-z plane
If (Abs(dDenom) <= 0.000001) Then
aRotAngles(0) = 0#
Else
If (dNumer / dDenom >= 1#) Then
dAcosValue = 0#
Else
If (dNumer / dDenom <= -1#) Then
dAcosValue = PI
Else
dAcosValue = Acos(dNumer / dDenom)
End If
End If
aRotAngles(0) = Sgn(dB) * dAcosValue
oAxis.X = 1
oAxis.Y = 0
oAxis.Z = 0
Call oRotate.SetToRotation(aRotAngles(0), oAxis, oCenter)
Call oMatrix.PreMultiplyBy(oRotate)
End If
'
' Choose aRotAngles[1] about y which transforms axes[3] onto the z axis
'
If (oMatrix.Cell(3, 3) >= 1#) Then
dAcosValue = 0#
Else
If (oMatrix.Cell(3, 3) <= -1#) Then
dAcosValue = PI
Else
dAcosValue = Acos(oMatrix.Cell(3, 3))
End If
End If
aRotAngles(1) = Math.Sgn(-oMatrix.Cell(1, 3)) * dAcosValue
oAxis.X = 0
oAxis.Y = 1
oAxis.Z = 0
Call oRotate.SetToRotation(aRotAngles(1), oAxis, oCenter)
Call oMatrix.PreMultiplyBy(oRotate)
'
' Choose aRotAngles[2] about z which transforms axes[0] onto the x axis
'
If (oMatrix.Cell(1, 1) >= 1#) Then
dAcosValue = 0#
Else
If (oMatrix.Cell(1, 1) <= -1#) Then
dAcosValue = PI
Else
dAcosValue = Acos(oMatrix.Cell(1, 1))
End If
End If
aRotAngles(2) = Math.Sgn(-oMatrix.Cell(2, 1)) * dAcosValue
'if you want to get the result in degrees
aRotAngles(0) = aRotAngles(0) * TODEGREES
aRotAngles(1) = aRotAngles(1) * TODEGREES
aRotAngles(2) = aRotAngles(2) * TODEGREES
End Sub
This code example is based on the theory from http://kwon3d.com/theory/euler/euler_angles.html
Philippe Leefsma
Developer Consultant
Developer Technical Services
www.autodesk.com/joinadn
Philippe Leefsma
Developer Technical Services
Autodesk Developer Network