GearHeads Corner

Art

I created the attached PivotEnergy.vcp & PivotEnergy2.vps files to investigate
the pivot energy setting. Each file has Body Energy Coefficient (BOE)=.99 and
varies PivotEnergy 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 simulation

  PivotEnergy.vcp Uses circles with off center center of gravity.Most of the
  circles except the .9 and 1.0 circles rapidly stop oscillating.

  PivotEnergy2.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 PivotEnergy2.vcp behaved like it did.

Based on the experiments, 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 rotational momentum?

Bill Michael

Hi Bill:


  Pivot Energy internally is called PivotFriction. Its applied to the rotationl body to simulate friction, it
is not linear but exponential so will have a great damping effect.

Art