.TH lookat  3 "R1c" "Silicon Graphics"
.SH NAME
.I lookat
- define a viewing transformation
.SH SYNOPSIS
.nf
.TP \w'FORTRAN\ \ \ 'u
C
.B "lookat(vx, vy, vz, px, py, pz, twist) "
.B "Coord vx, vy, vz, px, py, pz; "
.B "Angle twist;"
.IP 
.TP \w'FORTRAN\ \ \ 'u
FORTRAN
.B "subroutine lookat(vx, vy, vz, px, py, pz, twist)"
.B "real vx, vy, vz, px, py, pz"
.B "integer*2 twist"
.IP 
.TP \w'FORTRAN\ \ \ 'u
Pascal
.B "procedure lookat(vx, vy, vz, px, py, pz: Coord; twist: Angle);"
.sp
.SH DESCRIPTION
.I Lookat
defines the viewpoint and a reference point on the line of sight
in world coordinates.
The viewpoint is at \f3(vx, vy, vz)\f1.  The viewpoint and \f3(px, py, pz)\f1
define the line of sight.  \f3Twist\f1 
measures right-handed rotation about the \f3z\f1-axis in the 
eye coordinate system.
.SH "SEE ALSO"
.I polarview