Keying fluidsim in IPO

Support Animation and Rigging
#1

Can someone take me through the use of the fluidsim in the IPO editor?

I need the flow to start at 6 seconds into the animation and finish at around 14 seconds.
So I need to key the fac-time but how?

Any help greatly appreciated!

#2

Are you using a flow object or an inflow object?
For inflow you would just key the ‘Active’ channel.

For fluid and the fac-time ipo:

select the domain object
key the fac-time as follows:

  • basically fac-time runs from 0 to 1(vertically) 0 being the start, and 1 the end.
    so for a 14 second animation = 350 frames at 25 fps, if you have a linear line running
    from frame 0, y = [0] to 350, y = [1] there is no effect; you would see what you would normally see with no fac-time ipo.
  • a horizontal ipo line is like freezing the action, so for a flat line from (0,0) to (150, 0) would “freeze” the first 6 seconds of animation.
  • a steeper ipo line (say 2*) would double the speed of the fluid animation.

One thing to be mindfull of is that the start time is in seconds (=0) while Blender uses a start frame of 1; so if you’re not carefull you might get an “off by 1 frame” issue.

#3

Thanks a lot Jarell.
I googled the subject and couldn’t find anything!

To clarify:
I setup the domain and fluid.
Open IPO editor select fluidsim and fac-time.
Set the frame I want the fluidsim to start on the timeline.
Control-click on the IPO grid to set keyframe.
Then select the end time in the timeline.
Control-click on the IPO grid to set keyframe.

Tried that but no keying happens in the IPO editor.
What am I doing wrong?

#4

Set the frame I want the fluidsim to start on the timeline.
Then select the end time in the timeline.

You don’t need to set the frame before keying.
When you press [Ctrl]+ LMB (Left Mouse Button) click in the graph area of the IPO Curve Editor, you add a point like adding a point on an X(frame) vs Y(factor, in this instance) graph to get an "input vs. output type result.

Then tab into edit mode, select one of the points, press [n] to bring up the “transform properties” panel and enter an exact number in the fields at the bottom of the panel for each point.

#5

Thanks Jarell.
Great and timely advice!