Try replace :

eBall.x= (camera.x+cos(cam_ang.pan)*(cam_dist*cos(cam_ang.tilt)));
eBall.y= -1*(camera.y+sin(cam_ang.pan)*(cam_dist*cos(cam_ang.tilt)));
eBall.z= (camera.z+sin(cam_ang.tilt)*cam_dist);

to

vec_set(eBall.x,cam_dist.x);
vec_rotate(eBall.x,camera.pan);
vec_add(eBall.x,camera.x);
vec_set(eBall.pan,camera.pan);

Not tested btw.

Thanx Vlau

Unfortunately:

vec_set(eBall.x,cam_dist.x);
vec_rotate(eBall.x,camera.pan);
vec_add(eBall.x,camera.x);
vec_set(eBall.pan,camera.pan);

doesn't seem to work.

cam_dist is a var so only has one value not x, y, z. Although it would be possible to define separate values for each of these.

I think the problem is not with updating the position coordinates for eBall but its orientation. Not sure how to get this and pass it to eBall after executing the orbit function...

will try something else now...