On light preset, Light types Angle directional and Double-Angled directional functions only at 0º and 180º (±25º).
Direction and Direction2 parameters only work at 0º and 180º with a margin of ±25º. Trying to set a light to 90º with Direction and Direction2 parameters for cutoff planes, does not work.
Example:
In this scenario, light is directed along the X-axis at a 9º angle over the horizontal. The vector XY (1,-0.1) determines the cutoff plane normal.
Relative position: 0,1,0
Direction (Y/Z/X): 0, 0, 1
Direction2 (Z/X/Y): 0, 1, -0.1
In the second scenario, the light is directed along the Y-axis, at -90º with an angle of 9º over the horizontal
Relative position: 0,1,0
Direction: -1,0,0
Direction2: 0.1,1,0
Doesn’t work. Tried several combinations without success, getting weird results.
The cutoff plane appears to be set at intersecting the y-axis, regardless of the direction of the light, but should be able to intersect and rotate on the X-axis for lights pointing along or close to the Y-axis.
This type of lights are relevant and are used when creating PAI/VASI lights or lights with a specific beam angle.