Each  Placement3D  has 2 read-write properties that describe its transformation: 

• Matrix3D Placement3D::AbsoluteTransformation  – absolute transformation 
• Matrix3D Placement3D::RelativeTransformation  – transformation relative to a parent object 

The properties are represented by a 4x4 transformation matrix: 

M11      M12      M13     M14 

M21      M22      M23     M24 

M31      M32      M33     M34 

OffsetX OffsetY OffsetZ M44 

Here is an example of setting transformation matrix to a 3D object:

Vector3D oVector3D = new Vector3D();
oVector3D.X = 3.0;
oVector3D.Y = 4.0;
oVector3D.Z = 5.0;
Quaternion oQuaternion = new Quaternion(oVector3D, 2.0);
Matrix3D oMatrix3D = new Matrix3D();
oMatrix3D.Rotate(oQuaternion);
oMatrix3D.Translate(new Vector3D(1.0, 2.0, 3.0));
oComponent1.AbsoluteTransformation = oMatrix3D;

It is also possible to move a 3D object using the  Move()  method:

oComponent1.Move(1.0, 2.0, 3.0);

How to calculate transformation relative to a specified 3D object

Sometimes it is necessary to calculate the local transformation, i. e. relative to a specified 3D object.
For example, it could be the position of components on a rail from its beginning:

To calculate the position of the handle, it is necessary to use the  .RelativeTransformationOfMacro  property:

Matrix3D terminalTransformation = terminal.RelativeTransformationOfMacro;
var x_coordinate = terminalTransformation.Transform(new Point3D()).X;

How to calculate the position of edges of a component on a rail 

For this purpose, please use the  .Corners  property. At first, please recognize whether a rail is horizontally placed or vertically by checking its position according to a base line mate:

private bool isRailHorizontal(MountingRail rail)
{
    var baseMate = rail.BaseMate;
    return Math.Abs(baseMate.StartPoint.X - baseMate.EndPoint.X) > Math.Abs(baseMate.StartPoint.Y - baseMate.EndPoint.Y);
}

var terminalPosition = isRailHorizontal(rail)
                       ? Math.Abs( (terminal.Corners.LowerLeftBackAbsolute.X - rail.Corners.LowerLeftBackAbsolute.X))
                       : Math.Abs((terminal.Corners.LowerLeftBackAbsolute.Z - rail.Corners.LowerLeftBackAbsolute.Z));

Rotation angle of a 3D object

It can also be useful to get information about how an item was rotated during insertion from Placement options dialog:

To calculate this rotation, there should be used the  .RelativeTransformationOfMacro  property:

Matrix3D matrix = oPlacement3D.RelativeTransformationOfMacro;
double oRotationAngleZ = -1 * Math.Atan2(matrix.M21, matrix.M11) * (180.0 / Math.PI);