Well, I got it to work - though I was a little hasty and too lazy to calculate the velocity of the domino correctly and give that to the fluid, but bear with me - it’s not really that hard…
You’re going to hate this answer, but short of writing some python (which would take me longer anyway) you’re going to have to do some pen and paper calculations.
What I would do is measure the location of one of the vertices on the top of the domino (one of the two that hits the ground going the fastest) at both the frame before impact and the frame of impact. I’d do this by selecting it, snapping the 3d cursor to it then opening up the View->ViewProperties dialog - this will give you the position of the 3d cursor.
Then, I’d work out how far forwards it moved and how far downwards it moved, I’d write these two numbers down. Next, I’d look at the largest side of the domain and look at what I had the RealWorld units set to, I’d also write these two numbers down.
I’d then calculate how many meters/unit this works out to & write that down.:spin:
Then, I’d take this last number and multiply it by the number of units the vertex travelled in one frame. I now know how many meters per frame the object is moving when it hits the ground. Multiply that by 24fps and I have the number of meters per second it’s travelling at the time of impact. :whew!:
I just tried that, but it was all out of whack, muuuch too slow - then it dawned on me that the game engine is treating each unit as a meter when it does it’s calculations. Hmmm, so then I multiplied these numbers by the inverse of the domain RealWorld size (1/0.03 = 33) This seems to give quite a pleasing result, though to be honest, like much of the work one may do with fluids, I think (EDIT: I’m SURE) it may well be easier to go with some values that just look good.
But anyway, here’s all my figures in a worked example:
VertexX = -2.37
VertexZ = 0.12
VertexX = -2.39
VertexZ = -0.04
Travelled in 1 Frame:
X = -0.02 units
Z = -0.16 units
RealWorld Size: 0.03
Blender Units: 11.5
Meters/Unit: 0.03 / 11.5 = 0.0026 meters/unit
X = 0.02 * -0.0026 = -0.00005217 meters/frame
Z = 0.16 * -0.0026 = -0.000417 meters/frame
Velocity (meters/Second - uncorrected)
X = 24(fps) * -0.00005217 = -0.00012 m/s
Z = 24(fps) * -0.000417 = -0.010008 m/s
Velocity (meters/Second - corrected)
X = (1/0.03) * -0.00012 = -0.04 m/s
Z = (1/0.03) * -0.010008 = -0.33 m/s
:eek: Man, that’s way too much in the way of maths to be doing at 5:40am, but it does as I say, seem to give pleasing results. To be honest, I think it’d just be quicker and easier to take a guess at the initial velocity, bake at a resolution of about 50, render at 200*150 and insert into the sequence editor, SAVE the sequence editor file. Give it a try, and if it doesn’t work out, reopen the simulation file, tweak the values, re-render the fluid part, SAVE, then reopen the sequence file and re-render the sequence. Once a pleasing speed has been reached, go back and re-bake and re-render everything at a more suitable resolution.
Jebus! Did I really write that much??
Hmm, told you you weren’t going to like my answer…
Time for some breakfast methinks… enjoy!!