Changing the material while running

Hello,

changing the matrial is of particles is as easy as

b = O.bodies[someID]
b.mat = someOtherMaterialInstance # b.material = ... also works

but be careful, that change of material have NO effect on already existing
interactions!

The error you get is because of python types (as the error message says).
You can try O.bodies[i] instead of O.bodies[n]:

def change():
    for i in n:
        if O.bodies[i].state.pos[2] <= 1:# should be O.bodies[i] instead of
O.bodies[n]???
            #for i in n: # Why this second loop?
                O.bodies[i].material = O.materials[frict] # As suggested by
Alex, assign material directly, not its label
                ...

cheers
Jan

2015-03-17 13:21 GMT+01:00 Shenyang Cai <
<email address hidden>>:

> New question #263780 on Yade:
> https://answers.launchpad.net/yade/+question/263780
>
> Hi all!
>
> I want to change the material of certain spheres while running the
> program, and here is my script:
>
>
> from yade import pack
>
> frict=O.materials.append(FrictMat(young=1e6,
> poisson=0.3,
> density=2600))
> con=O.materials.append(CpmMat(young=1e6,
> poisson=0.3,
> epsCrackOnset=0.1,
> relDuctility=0,
> density=2600))
>
> floor=utils.wall(position=(0,0,0), axis=2, material=frict)
> O.bodies.append(floor)
>
> sp1=pack.SpherePack()
> sp1.makeCloud((-0.5,-0.5,1),(0.5,0.5,2),rMean=0.05,rRelFuzz=0.2)
> m = sp1.toSimulation(material=con) #defining the lower cube of spheres
>
> sp2=pack.SpherePack()
> sp2.makeCloud((-0.25,-0.5,3),(0.75,0.5,4),rMean=0.05,rRelFuzz=0.2)
> n = sp2.toSimulation(material=con) #defining the upper cube of spheres
>
> for i in m:
> O.bodies[i].shape.color = (1,1,1)
>
> O.engines=[ForceResetter(),
> InsertionSortCollider([Bo1_Sphere_Aabb(aabbEnlargeFactor=1.7),
> Bo1_Wall_Aabb()]),
> InteractionLoop(
> [Ig2_Sphere_Sphere_ScGeom(interactionDetectionFactor=1.7),
> Ig2_Wall_Sphere_ScGeom()],
> [Ip2_CpmMat_CpmMat_CpmPhys(),
> Ip2_FrictMat_CpmMat_FrictPhys()],
> [Law2_ScGeom_CpmPhys_Cpm(),
> Law2_ScGeom_FrictPhys_CundallStrack()]
> ),
> NewtonIntegrator(damping=0.3, gravity=(0,0,-9.81)),
> PyRunner(command = "change()", iterPeriod = 300,label =
> "checker")
> ]
> O.dt=0.5*utils.PWaveTimeStep()
>
> def change():
> for i in n:
> if O.bodies[n].state.pos[2] <= 1: #when two cubes collide
> for i in n:
> O.bodies[n].material.label = frict #here I want to change
> the upper cube's material from CpmMat to FrictMat
> checher.command = "done()"
> return
>
> def done():
> return
>
>
>
>
> The error message is:
> ArgumentError Traceback (most recent call last)
> /usr/bin/yadedaily in <module>()
>
> /usr/bin/yadedaily in change()
> 38 def change():
> 39 for i in n:
> ---> 40 if O.bodies[n].state.pos[2] <= 1:
> 41 for i in n:
> 42 O.bodies[n].material.label = frict
>
> ArgumentError: Python argument types in
> BodyContainer.__getitem__(BodyContainer, list)
> did not match C++ signature:
> __getitem__(pyBodyContainer {lvalue}, int)
>
> I am wondering whether an object's material can be changed while the
> program is running .
> Thanks!
>
> --
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