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SET GLOBAL TRANSFORMATION 3

PSGMT3

CALL SEQUENCE

CALL PSGMT3 (XFRMT)

INPUT PARAMETERS

REAL XFRMT(4,4)
Homogeneous 4 x 4 array.

PHIGS STATE

(PHOP, *, STOP, *).

EFFECT

A SET GLOBAL TRANSFORMATION 3 element is inserted in the open structure after element pointer or replaces the element indicated by element pointer, depending on edit mode. Element pointer is updated and points to the SET GLOBAL TRANSFORMATION 3 structure element. The values specified by the parameters are associated with the element.

When the SET GLOBAL TRANSFORMATION 3 element is interpreted, XFRMT replaces the current global modelling transformation. An array multiplication is then carried out between the global modelling transformation (G) and the current local modelling transformation (L) to obtain the composite modelling transformation (C): C <---- G x L.

The modelling transformation sequences carried out during a structure traversal are:

- The traversal of a structure starts, the current global modelling transformation is equal to the composite modelling transformation inherited from the parent structure. If the SET GLOBAL TRANSFORMATION 3 is encountered, current global modelling transformation is replaced by the element encountered.

- The traversal of a structure starts, the local modelling transformation is equal to the identity matrix. If the SET LOCAL TRANSFORMATION 3 element is encountered, the specified transformation is used to modify the local modelling transformation according to the specified composition type.

- The current global modelling transformation is combined with the local modelling transformation to form the composite modelling transformation.

- The composite modelling transformation transforms the modelling coordinate (MC) system, used to define the geometrical structure elements, into world coordinates (WC). Also, it is inherited by the following structure in the structure network as being its global modelling transformation.

EXTENSION TO THE PHIGS STANDARD

If GPHIGS is in NRS mode, the effect of this function is different from the effect described in the standard.

In NRS mode, (see OPEN PIPE), the element is not stored in a structure. It is sent to the workstation on which the pipe is opened.

ERRORS

5
Ignoring function, function requires state (PHOP,*, STOP,*)

SEE ALSO

set local transformation 3, translate 3, scale 3, rotate x, rotate y, rotate z, compose matrix 3, build transformation matrix 3, compose transformation matrix 3, open structure, open pipe (ext), inquire current element content, inquire current element type and size

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