Ok, I've been trying to make a realistic looking tornado and this is what I've come up with so far. It's an alpha plane and I think it's a little too transparent. I've tried every thing I can think of to get it to look a little more solid. I've never seen a tornado up close (don't want to either) so I can't say if you can see through them or not. What do you think???

Here are the transparency settings:

The shape looks like a tornado that is either just starting or just ending. I've seen em up close and you can't see thru it or the clouds from which it is desending and the end tends to flatten and spread once on the ground from the debris it kicks up. I think you're on the right track however.

This could be a hard one. Here is an alpha plane picture of a real tornado I tried. Also with yours perhaps a spiral bump map added? Or a spiral object with a cloud like texture added as well? :) Well done.!!BTW

A little better but I still have to get some kind of spiral bump map to make it look more realistic.

This is starting to take shape, very nice. I was thinking what about making a bump map from a picture of a real Tornado? :)

I have the original picture this was created from. I'll try that as a bump map when I get a chance. If I can get this to look some what decent I can post it in the free section.

Almost there!!! Just needs a little more fine tuning. Background clouds on this could have been a little darker but I was just doing a quick render. I also think I need to soften up the contrast on the tornado so it doesn't look as hard.

Well done!! :)