Sorry if this post gets too long, but I really would like some guidance before I spend another month working on this scene. Thanks in advance for any help someone can give.
For some background - The scene I’m currently stuck on will be approximately 14 seconds long, and for the last 10 of those I’m trying to make what should look like a cloud, or column of smoke drifting very slowly to the left of the screen. It needs to appear to be kilometers (or miles) away from the camera, so the movement needs to be very small - like 50 pixels or so over that 10 seconds. But at the same time, the camera is moving into final position.
I’ve so far tried to do this with smoke sims, but I can’t figure out how to slow the whole thing down. I’ve managed to keep it from rising too high by altering the heat and gravity but then I have to speed up its creation to get the desired volume and this makes the overall motion way too fast.
I’ve tried using the volume rendering (including the cloud generator add-on), but since the “texture” of the smoke is actually applied to the domain, any motion of the “cloud” object looks terrible. Like shadows cast on a moving object, the shadows stay still and unchanging while the back ground moves. The camera motion compounds this effect. It’s also taking 6 to 15 minutes to render each frame. The last attempt was nearly 20 hrs for the 480 frames.
I’m going to try one more time moving the domain as well as the cloud object to see if this eliminates the apparent flickering. But I would really like to know if there is some other trick or technique I’m missing. I’ve also considered rendering a smoke sim for say 50 or 100 frames and using the sequencer to stretch that out over the 480. Is that even possible? I haven’t gotten to learning that portion yet.
I can post the blend if needed, but it’s nearly 5 mb so I wasn’t sure if I should or not.
I have attached a scaled down version with a penciled in area where the smoke should be, if that helps.
the latest version of blender (2.54 beta) now has the ability to scale the timing of smoke sims, effectively slowing down time. Check it out!!
I think your bigger issue is likely to be selling the scale of the smoke with the smoke sim. For smoke that far away, I would probably actually use particles… maybe big billboard particles with nicely lit smoke-puff texture, or possibly try using the volume material with a cloud texture on a mesh that gives you the shape you want.
In my experience (as an fx artist for video games), smoke in the distance like that can be achieved quite nicely with some simple billboard particles and a nice texture.
Thank you for that.
I’ll check out the new version first I think. I tried using billboard particles in 2.49, but not with much success. If the new version doesn’t help, I’ll revisit it.
I did try doing the volume with a cloud texture, but that was based on a domain object having the texture. If I understand you correctly, I’ll try it directly on the “smoke” object. At this point, I’m almost tempted to just texture a plane with a smoke render and move that slightly. I’m sure it would look pretty flat though.
So I tried voxelfog’s suggestion of trying the time scaling in 2.54 and if anyone is interested, this is what I’ve learned (right or wrong) so far.
The ability to scale the time and particle speeds is very close to what I’'m trying to acheive, but not quite there. If I leave all the default settings alone, the smoke will reach a decent volume in about 60 frames or so. Turning them down to the lowest settings (Time scale’s lowest is .2) increases the time to volume to over 200 frames. If I had known about this before animating everything else, I could have taken that into account, and not started animating at frame 1. So would the time offsets in the object panel help with this? If so, would that apply to the domain object, the emitter or both?
The other thing I found is that the heat and gravity settings of the smoke seem to be independent of the global settings. If I set gravity along the X axis to something non-zero, and set Z to 0, the smoke still tries to rise or fall in the Z. Setting heat and gravity in the smoke panel to 0 or something negative comes close to the desired effect, but it also makes the smoke more flat and blocky, and less billowing.