The following changes the direction of the view located at (500, 500, 500) and directed toward (0, 0, -1) (to rear of screen) toward the origin (0, 0, 0).
#define VIEW_PX 500.f
#define VIEW_PY 500.f
#define VIEW_PZ 500.f
#define VIEW_VX 0.f
#define VIEW_VY 0.f
#define VIEW_VZ -1.f
#define VIEW_ROLL 0
NJS_VIEW v;
v.px = VIEW_PX;
v.py = VIEW_PY;
v.pz = VIEW_PZ;
v.vx = VIEW_VX;
v.vy = VIEW_VY;
v.vz = VIEW_VZ;
v.roll = NJM_DEG_ANG(VIEW_ROLL);
njnjLookAtView(&v, 0.f, 0.f, 0.f);
njSetView( &v );
njClearMatrix();