Area lights in Mental Ray for lighting models and simple outdoor scenes with soft shadows

This setup can be used in conjunction with the Lume Glow skydome setup, replacing the Direct light with an mrArea Spot light.

This is a great way to get very controllable soft shadows.

Make sure mental ray and FG [final gather] are both on:

If you are converting from another kind of light you can run this script in the utilities tab

IMPORTANT

If you are going for that soft shadow, make sure you:
use a mr Area Spot
not a mr Directional light.

Use the DISC light for soft shadows

There is a very significant difference between using a disc ...

and a rectangle ...

Making the disc smaller sharpens the shadow but still keeps it soft.
[Pulling the light back has the same effect.]

Note -- in general you would not use the rectangle for soft shadows, but, if you expand the hotspot/falloff of the light enough, you will get a soft cast shadow:

If you think you notice any roughness to the shadow, you can increase the samples, which also increase render time.

5 samples on U and V

12 samples ... [slow] ...

Here is an example with shadow density pulled back to half: