how can I make my cloud cast a shadow?

I’ve been creating clouds both using the new Cloud Generator by Nick Keeline and also using particle systems from scratch. In every instance, when I light the cloud(s) from above, they cast a box-like shadow into the ground directly below them. I’m sure the ‘box shadow’ is the shadow of the reigon in which the particles are contained.

I was wondering if anyone knows of a way to make the clouds themselves cast shadows.

Thanks everybody!

I don’t know if it is a good idea to cast shadows from clouds generated by particle systems, it shall become heavy processing, if it is possible even… Maybe it should be better to simulate that.

Give the ground a material, in the shadow tab you need to check the “Receive transparent” option, that’s the whole magic.