How to render Slow-motion Smoke?

Support Particles and Physics Simulations
1

Hey guys,

I have an animation of a moving object, but I wanted to make it slow mo and it should be emitting smoke too.

So i went ahead and added time remapping Old frame to 25. Now it obviously renders 1 smoke sim per 4 frames.

How to fix this?
slowmO.blend (604.9 KB)

time scale in smoke settings is not helping at all.

2

Did a quick test, and for me time scale in smoke works as it should.

An alternative would be to increase the frame rate in Output. If you output a video file directly, you just have to change the FPS in the metadata afterwards.

1 Like
3

Thank you. But my actual scene is a bit complex, so i copy pasted the scene and re scale the key frames so its without time re mapping. then did the smoke sim with 0.03 value for temperature. Cheers!

This is great, Just for the knowledge sake. could you tell me more about the meta data? How do you change it?

4

There are plenty of tools I guess. Iā€™m on Linux and would use e.g. ffmpeg. No idea what one would use on Windows/Mac, but video transcoding tools often have that feature. What you do is just basically:

  • make Blender create a 100 FPS video
  • use tool to change the video file so it says it is actually 25 FPS (without changing the video frames itself at all)
  • video player will play it then at 25 FPS, thus it runs at a quarter of the speed Blender thought it would
5

Ah gotcha! the word meta data got me thinking down into wormholes. Cheers, Gold!

I just think that still blender doesnt have any data inbetween frames when i put time remapping to 25,

Heres an example

Since the time remapping is 25, i get 1 frame for every four frames. and i dont think rendering 100fps would help coz there will be nothing inbetween 4 frames for smoke.

:thinking:

6

You would have to disable time remapping for that. The reason why that approach was my second suggestion is, that you would have to adjust all anims (move the keyframes and such). It would all work the other way round. You would render just every 4th frame for the time range you want in normal time at 25fps and all frames for the slomo part.

7

Hmm i think thats the only way! cheers gold!