Odd smoke rendering issues + a question

I’m back to Blender after an extended break and have found loads of cool new features :smiley:

I’m playing around with the new smoke stuff and have an idea of something I want to do but I’m unable to get the effect I want.

http://dl.dropbox.com/u/909010/Forums/BlenderArtists/Screen%20shot%202011-06-11%20at%2012.08.30.png

Shows a flaming logo thing that I’d like to get looking better. This is animated in a video but the shot above shows the two issues I’m having. Just above the letters the smoke seems to be broken up into horizontal bands. The video seem to alternate 30 or so frames with the bands and then without. It looks pretty distracting yet I can’t figure out what is causing it. Lower resolution seems to help but then the letters don’t look right - this leads me onto the next issue.

I’d like the letters to have the smoke flowing smoothly out from the surfaces. As you can see in the image below fire tends to do this.

http://www.loupiote.com/photos_m/1112235738-torch-fire.jpg

But on my animation the letters seems to ‘fizz’. All the Blender smoke animations I can find on google show this effect. Is it something I’ll just have to live with?

My settings:
Hi-res FFT smoke with 160 divisions
Particle emitter with 50k particles over 250 frames - negative gravity to help.

I made a slick fire shader / node network that gives you epic results like this. I’m using it to promote the Rebel Squared dubstep release dubstep superheroes. I tried to make 3D fire many ways, then learned how to do it in real life (that’s the best!!!) and then learned to do it in ligthwave 3D with turbulance 4D and then I did it in blender 3D. If you’re interested, I could give you a test scene (privately). I’m going to release a tut this summer once I work out some glitches in the system.