Data Type	Member	Description
int	reason	Indicates why the callback was invoked.
XEvent *	event	Points to the event that triggered the callback.
XintView3DObject *	object	Object that was picked or selected.
XintView3DPickData	pick_data	Data associated with the point that was picked. (Set only if reason is XintCR_PICK)
int	side	XintSIDE_TOP, XintSIDE_BOTTOM or XintSIDE_UNKNOWN.
XintView3DEditVectorData	edit_vector_data	Structure containing information about the new location of the vertex being edited.

Structure XintView3DPickData is defined as follows:

    typedef struct {
                    XintVector3  point;          /* point that was picked */
                    XintVector3  normal;         /* Normal at intersection */
                    XintVector3 *vertex;         /* Closest vertex picked */
                    int          index;          /* Vertex index */
    } XintView3DPickData;

Structure XintView3DEditVectorData is defined as follows:

    typedef struct {
                    XintVector3  point;/* new value of vertex being edited*/
    } XintView3DEditVectorData;

Data Type	Member	Description
int	reason	Indicates why the callback was invoked.
XEvent *	event	Points to the event that triggered the callback.

The callback reason can be used to determine on which menu the help was requested.

Data Type	Member	Description
int	reason	Indicates why the callback was invoked.
XEvent *	event	Pointer to the XEvent that triggered the callback.
XintRayLeg3	ray	Information for the ray doing the selection and picking.
XintReal	distance	Distance of intersection between the ray and the objects.
Boolean	hit	True if ray intersects objects.
Boolean	do_view3d	True if using the View3D picking and selection algorithms.

Data Type	Member	Description
int	reason	Indicates why the callback was invoked.
XEvent *	event	Pointer to the XEvent that triggered the callback.
XintReal	azimuth	Current azimuth of the display (Rotation).
XintReal	dip	Current dip of the display (Rotation).
XintReal	twist	Current twist of the display (Rotation).
XintReal	zoom	Current zoom of the display (Zoom).
XintReal	x_offset	Current X offset of the display (Translation).
XintReal	y_offset	Current Y offset of the display (Translation).

Data Type	Member	Description
int	reason	Indicates why the callback was invoked.
XEvent *	event	Points to the event that triggered the callback.
XintView3DObject **	object_list	List of objects being removed from the View3D widget display list.
int	count	Number of objects being removed.
Boolean	doit	Set to False to prevent the objects from being deleted.