Speed control? 2004-08-15 - By Stephen Schick
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I'm stumped, and and any [advice/help/ideas/amusing anecdotes] would be
greatly appreciated!
I am attempting to animate a null along a path via a speed control.
There appear to be 2 options:
1. Work with deltas - for any time change, calculate the distance change
and add this to the current distance.
2. Calculate the whole distance travelled on any time change.
The problem with the delta solution is that any skipped frames, due to
scrubbing or jumping from frame-to-frame, will invalidate the calculation.
In our case, the speed control can be animated, and thus I need to be able to
determine the distance the null has travelled at any arbitrary frame.
So far I am using a scripted operator which sums the change in distance for
each frame up to the current frame, but needless to say this gets cripplingly
slow as the current frame gets further from the start frame:
-- ---- -----
currentFrame = In_UpdateContext.CurrentFrame
startFrame = GetValue( "PlayControl.In")
set speedo = activesceneroot.FindChild( "Speedo" )
for i = startFrame to currentFrame
set speed = speedo.EvaluateAt(i)
''' rotx of Speedo = units/sec
speedsum = speedsum + speed.rotx.Value
next
Out.Value = speedsum
-- ---- -----
This doesn't seem revolutionary, so I'm hoping someone might have tried
something similar before...
Thanks in advance!
Stephen.
--
I was never able to finish anything, but now
-- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ----
Stephen Schick sschick@(protected)
TD / 10th Level Grin Master T: 604.714.2600 x2133
Mainframe Entertainment F: 604.714.2641
200 - 2025 W. Broadway, Vancouver, BC V6J 1Z6
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