Non-touching interactions not being recognized as real, despite interactionDetectionFactor > 1

Hi Bruno,

I have turned setCohesionNow=True (in fact, I had it that way before I asked the question). The distant interactions are still non-real. Here is a list of my engines.

O.engines=[
 ForceResetter(),
 InsertionSortCollider([Bo1_Sphere_Aabb(aabbEnlargeFactor=1.5), Bo1_Facet_Aabb()]),
 InteractionLoop(
  [Ig2_Sphere_Sphere_ScGeom6D(interactionDetectionFactor=1.5), Ig2_Facet_Sphere_ScGeom6D()],
  [Ip2_CohFrictMat_CohFrictMat_CohFrictPhys(setCohesionNow=True, setCohesionOnNewContacts=True)],
  [Law2_ScGeom6D_CohFrictPhys_CohesionMoment(),Law2_ScGeom_FrictPhys_CundallStrack()]
 ),

 NewtonIntegrator(damping=damping, gravity=[0, 0, gravity], label='integrator')
]

Which engine could be causing the trouble?

Please post a simple but complete script showing the problem.

damping = 0.4 #ratio
gravity = -9.80665 #m/s

mat42 = O.materials.append(CohFrictMat(isCohesive=True, frictionAngle=radians(42), density=4200, poisson=0.42, young=4.2e9, alphaKr=0.242, alphaKtw=0.1642, normalCohesion=4.2e5, shearCohesion=8.4e5))
Mat42=O.materials[mat42]

O.bodies.append(utils.facet([(-42,-42,0),(42,-42,0),(0,63,0)],wire=False,color=(0.42,0.42,0.42)))
cld = pack.SpherePack()
cld.makeCloud((-1,-1,1),(1,1,5),rMean=0.25,rRelFuzz=0.3)
cld.toSimulation(material=Mat42)

O.engines=[
 ForceResetter(),
 InsertionSortCollider([Bo1_Sphere_Aabb(aabbEnlargeFactor=1.5), Bo1_Facet_Aabb()]),
 InteractionLoop(
  [Ig2_Sphere_Sphere_ScGeom6D(interactionDetectionFactor=1.5), Ig2_Facet_Sphere_ScGeom6D()],
  [Ip2_CohFrictMat_CohFrictMat_CohFrictPhys(setCohesionNow=True)],
  [Law2_ScGeom6D_CohFrictPhys_CohesionMoment(),Law2_ScGeom_FrictPhys_CundallStrack()]
 ),

 NewtonIntegrator(damping=damping, gravity=[0, 0, gravity], label='integrator')
]

O.run(1)

len(O.interactions)
#returns the number of "interactions", including distant contacts; usually between 150 and 250

allIntrs = []
for b in O.bodies:
    for i in b.intrs():
        allIntrs.append(i)
print len(allIntrs)
#always seems to return 0

Hi,
There are two problems in your script.
The first problem is completely unrelated to non-touching particles. It is a wrong usage of O.run(). That is why we need to see complete script. Always.

This means "start a timestep and start counting interactions" in parallel:
   O.run(1)
   count interactions

Obvisously if running one timestep is not a lot faster (and it is not) than counting interactions the result is junk.

You need to first run an iteration, then count:
   O.run(1,True)
   count interactions

The other problem is the tensile strength you define is less than the tensile force generated by the distant interactions. Make normalCohesion=1e20 and you will find 258 interactions with the above script. You can change the tensile strength of existing interactions/materials later (i.e. after iteration 1).

Thanks Chareyre, that solved my question.