Can anyone tell me the difference between Volumetric clouds and regular ole clouds in 3D. 

Please try to keep it a bit simple.
Thanks

i believe one of the differences is how lighting flows around or through them compare to each other

Density of cloud centers.  Both Vue 7 Infinite and Carrara 7 Pro have such clouds.  But you have to look at their renders and compare.

Here are two renders from Vue 7 Infinite using the same cloud: http://www.shonner.com/drafts/vue7_clouds.htm

Volumetric clouds are 3 dimensional.

Coldrake

Quote - Volumetric clouds are 3 dimensional.

Coldrake

Hmmm, I've used other cloud & fog type products which were 3D, but weren't sold as "volumetric" nor did they take so long to render.  Don't get it.

3D and volumetric are different things.  Both are 3D though.  A cube of fog is not volumetric.

3D models as used by Poser are just empty shells.  Use a simple primitive, like cube or sphere with texture and transparency to fake fog or clouds and only the outer surfaces effect the lighting.  True volumetric means the model is treated as if it had volume, lighting will be scattered, defused and refracted by this volume, producing more realistic effects.

In Carrara, volumetric clouds look like frayed cotton balls.  In Vue, volumetric clouds look like cotton balls that are clumpped together.  These are the defaults in both apps and can be adjusted more so in Vue.

Thank you so much for all your info folks.  I think I get it now :- )