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Author Topic: Experiment at understanding Pivot energy  (Read 1074 times)
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« on: January 15, 2020, 05:17:10 PM »


I created the attached PivotEner gy.vcp & PivotEner gy2.vps files to investiga te
 the pivot energy setting. Each file has Body Energy Coefficie nt (BOE)=.99 and
 varies PivotEner gy from ~0 (.0001) to 1.0 in steps of .1

In each case I do select all the shapes in the main layer so I can see
the movement of the center of gravity during the simulatio n
   PivotEner gy.vcp Uses circles with off center center of gravity.M ost of the
   circles except the .9 and 1.0 circles rapidly stop oscillati ng.

   PivotEner gy2.vcp  repeats the above using crosses.  The effect is the same
     except for the .0001 (~0) case.  The ~0 case seems to behave like the
    1.0 case.  This only happened when the value was less than .1.  I didn't
    expect the shape of the object to have any effect.

I have no idea why the .0001 case in PivotEner gy2.vcp behaved like it did.

Based on the experimen ts, it seems that as you lower the value of pivot energy
from the default .9999 the ability to maintain rotation about a pivot decreases .
Is this a form of friction or something to do with moment of rotationa l momentum?

Bill Michael

* PivotEnergy.vcp (1226.52 KB - downloaded 72 times.)
* PivotEnergy2.vcp (1193.65 KB - downloaded 61 times.)
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« Reply #1 on: January 18, 2020, 10:46:54 AM »

Hi Bill:

  Pivot Energy internall y is called PivotFric tion. Its applied to the rotationl body to simulate friction, it
is not linear but exponenti al so will have a great damping effect.

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