Problem about density Scaling

Looking at your script fragment, I don't understand what you are trying
to do.
There is an example of use in examples/timeStepperUsage.py.
B

Many thanks for the reply from Pro. Burno.
I want to simulate a triaxial test of steel spheres. And I write the script according the example file (timeStepperUsage.py). However, the script fails, and all the particles disappear after some steps.
Thanks a lot!

>And I write the script according the example

Is that a new script? Because the above is not like in the example.
If it is a new one please show it.

I modified the "triax.py" file in "example/concrete/", according to the example file of densityscale (timeStepperUsage.py).

The followin script is the modified part:

.....

O.engines=[
 ForceResetter(),
 InsertionSortCollider([
  Bo1_Sphere_Aabb(aabbEnlargeFactor=enlargeFactor,label='bo1s'),
  Bo1_Facet_Aabb()
 ]),
 InteractionLoop(
  [
   Ig2_Sphere_Sphere_ScGeom(interactionDetectionFactor=enlargeFactor,label='ss2d3dg'),
   Ig2_Facet_Sphere_ScGeom(),
  ],
  [
   Ip2_CpmMat_CpmMat_CpmPhys(cohesiveThresholdIter=O.iter+5),
   Ip2_FrictMat_CpmMat_FrictPhys(),
   Ip2_FrictMat_FrictMat_FrictPhys(),
  ],
  [
   Law2_ScGeom_CpmPhys_Cpm(),
   Law2_ScGeom_FrictPhys_CundallStrack(),
  ],
 ),
 PyRunner(iterPeriod=1,command="addForces()"),
 NewtonIntegrator(damping=.3,label="newton"),
 CpmStateUpdater(iterPeriod=50,label='cpmStateUpdater'),
 PyRunner(command='plotAddData()',iterPeriod=10),
 PyRunner(iterPeriod=50,command='stopIfDamaged()'),
      GlobalStiffnessTimeStepper(label='ts'),
]

# run one step
O.step()

# reset interaction detection enlargement
bo1s.aabbEnlargeFactor=ss2d3dg.interactionDetectionFactor=1.0

O.timingEnabled=1
ts.active=True
newton.densityScaling=True

#... but not that of cell, hence we have to adjust it or the problem becomes unstable
for b in O.bodies:
    if isinstance(b.shape,Sphere):
        b.state.mass=1.0e20*b.state.mass

# initialize auto-updated plot
if runInGui:
  .........

Thanks a lot!

What is that?
> b.state.mass=1.0e20*b.state.mass

You don't find this in the example.

"
for b in O.bodies:
     if isinstance(b.shape,Sphere):
         b.state.mass=1.0e20*b.state.mass
"
This part is added by myself, to amplify the mass of each particle.
Thanks a lot!

So?
Removing those lines solved your problem?

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