PK_INSTANCE_sf_t

struct PK_INSTANCE_sf_s
    {
    PK_ASSEMBLY_t   assembly;   --- owning assembly
    PK_TRANSF_t     transf;     --- transform (must be a rigid motion,
                                --- reflection or PK_ENTITY_null)
    PK_PART_t       part;       --- instanced part
    };

typedef struct PK_INSTANCE_sf_s PK_INSTANCE_sf_t;


Specific Errors:
    PK_ERROR_not_in_same_partition  'assembly', 'transf' and 'part' are not in
                                    the same partition (MILD)

Used in:

PK_INSTANCE_ask
PK_INSTANCE_create

A PK_INSTANCE_sf_t contains the definition of an INSTANCE. If the transform is
PK_ENTITY_null, then it is treated as the identity transform.