@M4Rc0
With a little bit of trig you can do it quite easily.
Pick a point on a plane that you want to pivot around. In my example I will use the x,z plane so I will be rotating around the y axis at point (50,0,100). Pick the distance from the point that you want the arc to be (the radius actually). And pick an angle to rotate.
Then, using x = radius * cos(angle) + x point to rotate around
and z = radius * sin(angle) + z point to rotate around, you can easily do your pivot. If you want the object to face the point it is arcing around then use the command POINT OBJECT to keep it facing the point of pivot.
Here's an example:
sync on
sync rate 60
rem a cube so we can see what direction it is facing
make object cube 1,25
rem the point we want to rotate around and the distance
posx=50
posz=100
radius=50
rem position the camera and tilt it down 45 degrees
position camera 50,200,0
point camera 50,0,50
do
rem the angle and the resulting x and z coordinates
ang#=wrapvalue(ang#+1)
x#=radius*cos(ang#)+posx
z#=radius*sin(ang#)+posz
rem reposition the object at the new coordinates and point it at our focus
position object 1,x#,0,z#
point object 1,posx,0,posz
sync
loop
Enjoy your day.