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[Václav Šmilauer <eudoxos@xxxxxxxx>]

Hi, thanks for your responses. One thing that I find baffling...

I create a facet that reads like this in the .xml file:

   <physicalParameters _className_="BodyMacroParameters"  se3="{0 0 0 1
0 0 0}" mass="0" velocity="{0 0 0}" inertia="{0 0 0}"
angularVelocity="{0 0 0}" young="70000" poisson="0.2"
frictionAngle="0.5236" />
   <geometricalModel _className_="Facet"  diffuseColor="{1 1 1}"
wire="1" visible="1" shadowCaster="0" vertices="[{1 0 0} {0 1 0} {-1 0
0} {0 -1 0}]" />
   <interactingGeometry _className_="InteractingFacet"  diffuseColor="{1
1 1}" vertices="[{1 0 0} {0 1 0} {-1 0 0} {0 -1 0}]" />

The intent was to have unit square slab in the xy plane; its
se3.position is in the origin. However, in the rendering, I get facet
with 5 edges!

I am attaching the code and screenshot of the rendering.

> Edge is the intersection of two faces.
> Since the facets are distinct objects, and they are not connected to any 
> combinatorial structure (such as, for example, triangulation), the scope of 
> interaction with an edge will be the scope of interaction with two faces 
> simultaneously. To exclude such a dual interaction imposed edges as separate 
> body. (Similarly for vertices as the intersection of two or more edges).
>   
I find edges useful only if there is falling onto a convex object
between two facets, such that in the direction of both facets, there
will be no projection of the sphere on the respective facet; the sphere
would fall through then, right?
>> I tried running your model but didn't succeed (will investigate shortly).
>>     
> What happened?
>   
That was a bug with initializers I fixed now (r1401)
>> They > are calculated in postProcessAttributes, is that why in your example,
>> you save the simulation and load it again? 
>>     
>
> Yes.
>   
Added that to the python wrappers - see in the attached script.

# encoding: utf-8
o=Omega()
from yade import utils
from math import *

from yade.wrapper import *
def facet(center,vertices,relative=False,young=30e9,poisson=0.2):
	if not relative: relCenter=[0,0,0]
	else: relCenter=center
	vStr='['+' '.join(['{%g %g %g}'%(v[0]-relCenter[0],v[1]-relCenter[1],v[2]-relCenter[2]) for v in vertices])+']'
	b=Body()
	b.shape=GeometricalModel("Facet",{'wire':True,'visible':True})
	b.shape.setRaw('vertices',vStr)
	b.mold=InteractingGeometry("InteractingFacet")
	b.mold.setRaw('vertices',vStr)
	b.mold.postProcessAttributes() # calculates normals etc. - instead of saving and loading the whole simulation
	b.phys=PhysicalParameters("BodyMacroParameters",{'se3':[center[0],center[1],center[2],1,0,0,0],'mass':0,'inertia':[0,0,0],'young':young,'poisson':poisson})
	b.bound=BoundingVolume('AABB',{'diffuseColor':[0,1,0]})
	b['isDynamic']=False
	return b

o.bodies.append(facet(center=[0,0,0],vertices=[[1,0,0],[0,1,0],[-1,0,0],[0,-1,0]],young=7e4))
o.bodies.append(utils.sphere([.1,0,1],0.2,wire=False,young=7e4))
o.bodies.append(utils.sphere([0,-.1,1.5],0.2,young=7e4))
o.bodies.append(utils.sphere([0,.1,2],0.2,young=7e4))
o.dt=1e-5

o.initializers=[
	StandAloneEngine('PhysicalActionContainerInitializer'),
	MetaEngine('BoundingVolumeMetaEngine',[EngineUnit('InteractingSphere2AABB'),EngineUnit('InteractingFacet2AABB'),EngineUnit('MetaInteractingGeometry2AABB')])
]

o.engines=[
	StandAloneEngine('PhysicalActionContainerReseter'),
	MetaEngine('BoundingVolumeMetaEngine',[
		EngineUnit('InteractingSphere2AABB'),
		EngineUnit('InteractingFacet2AABB'),
		EngineUnit('MetaInteractingGeometry2AABB')
	]),
	StandAloneEngine('PersistentSAPCollider'),
	MetaEngine('InteractionGeometryMetaEngine',[
		EngineUnit('InteractingSphere2InteractingSphere4SpheresContactGeometry'),
		EngineUnit('InteractingFacet2InteractingSphere4SpheresContactGeometry'),
	]),
	MetaEngine('InteractionPhysicsMetaEngine',[EngineUnit('SimpleElasticRelationships')]),
	StandAloneEngine('ElasticContactLaw'),
	DeusExMachina('GravityEngine',{'gravity':[0,0,-10]}),
	DeusExMachina('NewtonsDampedLaw',{'damping':0.2}),
]

o.run(5)

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