alpha channel == 0 shader

[Dubbie]

Is there a shader in terragen2 that I can apply to my planet to make it render black with a alpha channel of value 0?

I want to render my sky and clouds in terragen and composite it over a landscape rendered in another application.
If this shader does not exist, is there an SDK that would allow me to write my own shader?

Regards,

Rhys.

[TheBlackHole]

In the planet node, turn off Surface visible. You should now get a groundless environment.

[Dubbie]

Thankyou very much for your tip. Switching off Surfaces Visible in the render node did the trick!