| So you want pointentity only at one axis? You could copy PointEntity from the engine to your main program, and take out two of the three angles to do that.|
In maths, you would need to use atan2 to achieve this. These are 2D maths.
If you have two 2d coordinates, you can calculate the angle from point 1 to point 2 using atan2:
angle# = atan2( y2-y1, x2-x1 ) 'gives angle between (x1,y1) and (x2,z2)
The 3d scene could be seen as a 2d world lying down. Then, the y-coordinate is not important, and you only take x and z in account:
angle# = atan2( z2-z1, x2-x1 )
Here is a working sample: