Free Flow

[JHaywood]

I just started using Fume and was wondering what exactly the "Free Flow" does? The help file gives some information, but I don't quite get what it's saying, "Free Flow - If you check this, source parameters will still influence channel values, but the source, itself, will behave just like fluid. As a result, the source’s velocity will not interrupt fluid movement in any way."

Can someone give me a real-world example of the difference between turning this on or leaving it off?

[ddiener]

As i understood, it is like a collision-thing. With FF-off, smoke/fire will collide with the source, beeing blocked. FF-on means: smoke/fire/fuel are "flowing free", not colliding with the source.

[JHaywood]

Thanks, that makes sense.

[vjeko]

Think like this: solid source is like an object, and free flow (with velocity 0) is like a "brush" in a paint program. Non solid, not free flow source is somewhere in between - the difference isn't completely intuitive.
If you need powerful push (like source spewing fire), or collision object, use solid source.
If you need to add some fire or smoke, or run some expression, while not disturbing anything else, use free flow.
For usual fire or smoke, try plain source first.

Vjekoslav