Workspace - Directional Lights

[trueBlue]

Does anybody have any experiences using Directional Lights with VRay?
Best I can tell:
1) Model does not have a Directional light in its UI
2) It seems that the Workspace - Directional light's Shadow On|Off and Color is the only attributes that VRay uses
3) It seems that the Workspace - Directional light's Size being cast can show in both directions when at 180 degrees
4) From the VRay pdf, supposedly Distant lights are supported
Is a Directional light a Distant light?

Lights
VRay supports Point lights, Spotlights, Distant lights, Projector lights and Area lights.

Directional light
Directional lights cast light rays only in one direction and only within a cylinder shape specified by the Size
parameter. Attenuation parameters work the same as for Omnidirectional lights. Like Spotlights and Projector Lights,
Directional lights can cast shadows.
* Size– Controls the radius of the cylinder of light.
* Color – Controls the color (and intensity) of the light.
* AttConstant – Constant attenuation does not depend on distance.
Values greater than 1.0 will make the light darker (2.0 means half
intensity), and values in the range 0...1 will make the light brighter (0.5
means double intensity).
* AttLinear – Specifies a linear attenuation coefficient. The light grows less intense with distance, with a linear
relationship between distance and intensity.
* AttQuadratic – Specifies a quadratic attenuation coefficient. The light grows less intense with distance, with a
relationship to the square of the distance (light will grow less intense more rapidly than with a linear attenuation).
* Threshold Attenuation – This specifies a final light intensity that is considered as zero – any pixel in an area
with intensity of less than this value is considered “not lit”. This parameter acts to speed up the processing of the
light (a higher value will class more points as unlit, and so reduce processing).
* Enable Shadow – If checked, the light will cast shadows in real-time. Shadow parameters are found in the
Advanced aspect

[clintonman]

I directional light effect will change based on it's position. A distant/infinite light only uses it's orientation, not it's position. I think directional is only a real time/d3d light in truespace.

[trueBlue]

Thanks for the clarification
So Distant lights is another name for Infinite lights, now I get it