I’ve been reading some older threads that talked about problems with no solutions that others have had deactivating gravity for smoke simulations. Is it really not possible to deactivate gravity for smoke so it doesn’t drift up automatically?
All I want to do is make a particle driven smoke/fire explosion in space, which I would think would be a common thing to do in 3D animation.
I have a decent looking explosion with smoke and fire which works fine, except I can’t turn off the gravity. When the smoke floats “up” in space (where there is no “up”) it breaks the illusion.
That’s an interesting theory 3pointEdit. Thank you for the reply.
As soon as I’m in front of Blender again I’ll take a look at what effect adjusting the heat properties has. I’m a little worried that turning down the heat might affect the fire effect in a way that would prevent a good explosion effect, but I’ll have to wait and see.
You’re going for a “Hollywood” explosion, right? Is it set in the vacuum of space, or inside an air filled room? Can you show or describe how it would look?
For something remotely plausible or realistic, a smoke/fire sim won’t be appropriate. Not in the airlessness of space or even an air-filled room in microgravity.
Heh heh. Yes Spaced you find me out; I am seeking a Hollywood style space explosion as in the kind with which George Lucas so thoroughly ruined the public’s understanding of the airless vacuume of space. I kind of thought that was obvious since I said I wanted a “smoke/fire explosion in space,” but I should have clarified. My apologies.
Using 3pointEdit’s theory I actually have some promising results achieved just using the following simple setup:
-particle system applied to default cube (lifetime. = 200)
-particle/render = none
-“Quick smoke” applied to default cube.
-Cube/smoke/Flow Source = the particles
-Cube/smoke/Temp Diff = 0
-Domain/smoke/Temp Diff = 0
-Cube/smoke/Flow type = Fire + Smoke
-Cube/Field Weights/Gravity = 0
It doesn’t look good, but at least the gravity problem is solved. When I have more time I’ll experiment some more and report back. Thank you for your reply Spaced and thank you again 3pointEdit. I will probably be back with more questions.
Use a sphere emitter or some forcefields to get rid of the cube look. Or add some randomness to the particle system. With density, gravity, and tempdiff all zero’d out, the smoke doesn’t really go anywhere except straight along the normal. Nothing else is influencing it.
You know that in Star Wars they actually shot the explosions from above. The fireball erupted towards camera, which the audience assumed to be horizontal. Giving the effect of altered gravity.
Nothing is really obvious here on BlenderArtists, everyone has an individual interpretation of what is being asked - and often there may be multiple solutions.
I wouldn’t be so quick to dismiss the intelligence of the audience, Gravity’s massive destruction scenes and fire effects were rather well received.
As for Hollywood-style space explosions, why not recreate the effect like they did in Hollywood? Fire sim with regular gravity viewed from above or below?
Edit: clearly I had this tab open far too long… as 3pointEdit says
Too true! It was poor form on my part. It’s been a while since I’ve tried to be an active forum member.
Now there I have to disagree. Movie watchers are second in gullibility only to American News watchers (speaking from personal experience here as I am an American ). Gravity began with a text card explaining that Star Wars was a lie and that there’s no noise in space. Ignoring for the moment that it only played by those rules for a few action scenes before re-introducing space sound effects later in the movie, I think if you had a text card at the beginning of a movie saying that 1 + 1 = 17 most of the audience would believe it and the rest would suspend their disbelief for so long that they eventually forget it wasn’t true too. But maybe I’m wrong; I have been watching a lot of “News” lately.
Anyway, thank you Spaced and 3pointEdit for the ideas. I am still experimenting with the method of turning off the heat. If I’m more successful I’ll post information about it here for future reference. I do like the idea of rendering explosions for some shots in an old-school style method from above like they did/do with physical models, but it wouldn’t hold up very well with a dynamically moving camera. It might work really well for other shots though so thanks again for the ideas.
FYI the sound effects in Gravity all followed a rule. You could hear explosions from the astronauts point of view if they were in direct physical contact with an object, like the Soyuz or iss etc. I guess the idea was transmission of sound through the suit.
I didn’t mean “Hollywood explosion” in a derogatory way (well, maybe just a little), but more like ‘expanding-gas fireball with complimentary expanding planar shockwave’.
In a typical flying and shooting spacecrafts scene, smoke & fire explosions aren’t likely to be the most implausible thing
If your exploding-object is moving, then your dimwitted audience might accept a moving explosion. This would let you do a rising-smoke fire sim and animate it’s position to make the top of the smoke appear stationary.
