IDLgrModel::GetCTM

The IDLgrModel::GetCTM function method returns the 4-by-4 double-precision floating-point graphics transform matrix from the current object upward through the graphics tree.

Syntax

Result = Obj->[IDLgrModel::]GetCTM( [, DESTINATION=objref] [, PATH=objref(s)] [, TOP=objref to IDLgrModel object] )

Return Value

Returns the 4-by-4 double-precision floating-point graphics transform matrix from the current object upward through the graphics tree.

Arguments

None

Keywords

DESTINATION

Set this keyword to the object reference of a destination object to specify that the projection matrix for the View object in the current tree be included in the returned transformation matrix. The resulting matrix will transform a point in the data space of the object on which the GetCTM method is called into a normalized coordinate system (-1 to +1 in X, Y, and Z), relative to the View object that contains the model object.

PATH

Set this keyword to a single object reference or a vector of object references. This keyword specifies the path in the graphics hierarchy to compute the transformation matrix. Each path object reference specified with this keyword must contain an alias. The transformation matrix is computed for the version of the object falling within that path. If this keyword is not set, the PARENT properties determine the path from the current object to the top of the graphics hierarchy and no alias paths are pursued. If IDLgrModel::GetCTM is called from within a Draw method, with the DESTINATION keyword set and the PATH keyword not set, the alias path used to find the object during the draw is used, rather than the PARENT path.

Note: For more information on aliases, refer to the ALIAS keyword in IDLgrModel::Add.

TOP

Set this keyword equal to the object reference to an IDLgrModel object to specify that the returned matrix accumulate from the object on which the GetCTM method is called up to but not including the specified model object.

Version History

5.0	Introduced