I'm simulating two M16x75 bolts (0.075m long),
each about 120 grams. 75 masses per bolt, about
1.5 grams per mass. All connections are generated
with the default length. I set stiffness to 750 and
dampening to 375, to keep deformations acceptable.

Everything works fine, but slow, because I need to set
time_step to 1/1400000 to prevent the instability warning.
From the source I understand that the warning is
generated when acceleration is more than 1e7. F=m*a so
there is a 10000 N force acting on (one of) my masses.
All of this is happening while by bolts are still
free-floating in mid-air. I never get an instability
warning during the rest of the simulation when the actual
collisions happen.

Can someone tell me more about what might course this
large force? Is it just that some masses are moved by
gravity, and are pulling in the not-yet-moved masses?

Can there be small rounding errors in the initial position
of the masses or the length of the connections?
The .DAT file seems to have sufficient deciaml places for
the mass length position and speed in my situation.

jaap

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