ball_collision.scn

<Node name="root" dt="0.05" gravity="0 -9.810 0">
    <VisualStyle displayFlags="hideBehaviorModels hideCollisionModels hideMappings hideForceFields showVisualModels hideInteractionForceFields" />
    <RequiredPlugin name='SofaMiscCollision'/>
    <RequiredPlugin name="SofaPython" pluginName="SofaPython" />

    <FreeMotionAnimationLoop solveVelocityConstraintFirst="0" />
    <LCPConstraintSolver maxIt="1000" tolerance="1e-6" initial_guess="false" build_lcp="true" multi_grid="false" printLog="0" mu="1.9"/>

    <CollisionPipeline depth="6" verbose="0" draw="0" />
    <BruteForceDetection name="N2" />
    <!-- <LocalMinDistance name="Proximity" alarmDistance="03" contactDistance="01" useLMDFilters="0" /> -->
    <MinProximityIntersection name="Proximitty" alarmDistance="3.0" contactDistance="1.0" />
    <CollisionResponse name="Response" response="FrictionContact" />


    <Node name="Input">
        <PythonScriptController filename="keyboardControl.py" classname="KeyboardControl"/>
        <!-- <PythonScriptController filename="sofaTest.py" classname="clothMesh"/> -->
        <MechanicalObject template="Rigid" name="DOFs" position="0 0 0  0  0  0  1.0"/>
        <Node name="VisuAvatar" activated="true" >
            <OglModel name="Visual" fileMesh="mesh/sphere.obj" color="blue" scale="1"/>
            <RigidMapping input="@.." output="@Visual"/>
        </Node>
        <Node name="RefModel">
            <MeshObjLoader filename="mesh/sphere.obj"  name="loader"/>
            <Mesh src="@loader"  />
            <MechanicalObject src="@loader" name="instrumentCollisionState" />
            <RigidMapping />
        </Node>
        
    </Node>



    <Node name="ball">
        <EulerImplicitSolver name="ODE solver" rayleighStiffness="0.05" rayleighMass="1.0" />
        <CGLinearSolver name="linear solver" iterations="25" tolerance="1e-10" threshold="10e-100" /> 
        <MechanicalObject name="ballState" template="Rigid3d"/>
        <UniformMass name="mass" totalmass="0.1" />
        <LCPForceFeedback activate="true" forceCoef="0.001"/>
        <UncoupledConstraintCorrection compliance="100"/>
        <Node name="ball_surf" >
            <MeshObjLoader name="meshLoader" filename="mesh/sphere.obj" />
            <Mesh src="@meshLoader" />
            <MechanicalObject name="ballCollisionState" template="Vec3d" src="@meshLoader" scale="3" translation="0 0 0"/>
            <UniformMass totalMass="0.1" />
            <UncoupledConstraintCorrection compliance="1"/> 
            <RigidMapping input="@.." output="@ballCollisionState"/>
            <Node name="VisualModel" >
               <OglModel name="ballVisualModel" src="@../meshLoader" color="1.0 0.2 0.2 1.0" scale="3" translation="0 0 0"/>
               <IdentityMapping input="@.." output="@ballVisualModel"/>
            </Node>

        </Node>
        <Sphere />

        <VectorSpringForceField  object1="@Input/RefModel/instrumentCollisionState" object2="@ball/ball_surf/ballCollisionState" stiffness="100000" viscosity="0" />

    </Node>

    <Node name="Floor">
      <MeshObjLoader name="loader" filename="mesh/floorFlat.obj" triangulate="true" scale="10" translation="50 -10 50"  />
      <MeshTopology src="@loader" />
      <MechanicalObject src="@loader" name="DOFs" template="Vec3d"  />
      <Triangle simulated="0" moving="0" contactFriction="100"/>
      <Line simulated="0" moving="0" contactFriction="100"/>
      <Point simulated="0" moving="0" contactFriction="100"/>
      <OglModel name="FloorV" />
    </Node>

</Node>

keyboardControl.py

import Sofa

class KeyboardControl(Sofa.PythonScriptController):
	# called once graph is created, to init some stuff...
	def initGraph(self,node):
		print 'initGraph called (python side)'
		self.MechanicalState = node.getObject('DOFs')
		gravity = node.findData('gravity').value
		print gravity
		self.rootNode = node.getRoot()
		#self.clothMesh = self.rootNode.getChild('SquareGravity')
		self.ballMesh = self.rootNode.getChild('ball')
		self.node = node
		# print self.ballMesh.getObject('ballState').scale
		return 0
	 
	 
	# key and mouse events; use this to add some user interaction to your scripts 
	def onKeyPressed(self,k):
		
		# free_position is a scalar array : [tx,ty,tz,rx,ry,rz,rw]
		free_position=self.MechanicalState.free_position

		# translation speed
		speed = 1 

		# UP key : front
		if ord(k)==19:
			self.rootNode.reset()
		# DOWN key : rear
		if ord(k)==21:
			self.rootNode.cleanup()
		# LEFT key : left
		if ord(k)==23:
			free_position[0][1]-=speed	
			self.MechanicalState.free_position=free_position
		# RIGHT key : right
		if ord(k)==22:
			free_position[0][1]+=speed
			self.MechanicalState.free_position=free_position
		# PAGEUP key : up
		if ord(k)==18:
			free_position[0][0]-=speed
			self.MechanicalState.free_position=free_position
		# PAGEDN key : down
		if ord(k)==20:
			free_position[0][0]+=speed
			self.MechanicalState.free_position=free_position
			
		
		print self.ballMesh.getObject('ballState').position, self.node.getObject('DOFs').position
		
		return 0 
	 
	# def reset(self):
	# 	print 'reset'
	# 	return 0

	# def cleanup(self):
	# 	print 'cleanup called (python side)'
	# 	return 0