03-06-2009, 11:26 AM
The scene is simple but has 1000 frames so debugging it is tedious.
So I'll ask a couple of questions here hoping that someone had this problem and solved it
The scene: simple source emitting only smoke (animated strength) and a rather strong side wind balanced with the velocity damping in FFX ( basically a chimney smoke).
1. I noticed that changing the grid resolution changes the simulation. ie.:
- cell size 20: in 100 frames the smoke goes all the way to the other side of the frame
- cell size 10: in the same 100 frames smoke reaches only the half (middle) of the frame width
- cell size 5: reaches about a quarter
It's as if a unit for velocity or strength was a single cell not a real world unit - is that correct?
2. I had the scene animation range 0-200 frames and left the simulation for night on range 0-1000. When I came back today and changed the animation range to 0-1000 to view the simulation - it looked good till frame 200 and then something strange started to happen with the smoke shape and even parts of the smoke seemed to freeze in space, while other just passed them by.
When I resimulated with the animation range 0-1000 the problem did not occur.
Is there a bug with simulating out of animation range. I'm just asking as I was unable to recreate it in a shorter scene
3. The simulation up to frame 200 looks great, good clumpy detail, but afterwards the detail seems to elongate, as if a horizontal direction blur was added. The velocity of the fumes seems constant, so the smoke doesn't seem to speed up there (no animation on wind or velocity damping).
Is it possible that the smoke travelling trough the grid creates (through heat or pressure) some sort of a tunnel that after a while influences the shape of the smoke?
Like I said general questions here as submitting the scene would ask everyone to simulate a 1000 frames sim
So I'll ask a couple of questions here hoping that someone had this problem and solved it
The scene: simple source emitting only smoke (animated strength) and a rather strong side wind balanced with the velocity damping in FFX ( basically a chimney smoke).
1. I noticed that changing the grid resolution changes the simulation. ie.:
- cell size 20: in 100 frames the smoke goes all the way to the other side of the frame
- cell size 10: in the same 100 frames smoke reaches only the half (middle) of the frame width
- cell size 5: reaches about a quarter
It's as if a unit for velocity or strength was a single cell not a real world unit - is that correct?
2. I had the scene animation range 0-200 frames and left the simulation for night on range 0-1000. When I came back today and changed the animation range to 0-1000 to view the simulation - it looked good till frame 200 and then something strange started to happen with the smoke shape and even parts of the smoke seemed to freeze in space, while other just passed them by.
When I resimulated with the animation range 0-1000 the problem did not occur.
Is there a bug with simulating out of animation range. I'm just asking as I was unable to recreate it in a shorter scene
3. The simulation up to frame 200 looks great, good clumpy detail, but afterwards the detail seems to elongate, as if a horizontal direction blur was added. The velocity of the fumes seems constant, so the smoke doesn't seem to speed up there (no animation on wind or velocity damping).
Is it possible that the smoke travelling trough the grid creates (through heat or pressure) some sort of a tunnel that after a while influences the shape of the smoke?
Like I said general questions here as submitting the scene would ask everyone to simulate a 1000 frames sim