Changing the scene file during the simulation and applying the changes without breaking the simulation

[zbounik]

Hi,

How can I enable or disable a component (e.g the ODESolver) in the middle of the simulation by adding a key control? Is there any way other than using the handleEvent() function?

Best,
Zahra

[hugtalbot]

Hi @zbounik
Activating/de-activating is possible only for nodes (see the associated data activated or sleeping).

You can although destroy components in python if you would like, but this might have strong side-effects..
e.g.

nodeToDelete = self.rootNode.getChild(str(name))
for obj in nodeToDelete.objects:
     nodeToDelete.removeObject(obj)
self.rootNode.removeChild(str(name))

[zbounik]

Thank you.

[damienmarchal]

Hi @zbounik

The current way of changing a simulation at runtime to react to key pressed is to use a controller.

The simplest is to go with python. Here is an example:

import Sofa
from Sofa.constants import Key

class MyController(Sofa.Core.Controller):
     def __init__(self, *args, **kwargs):
          Sofa.Core.Controller.__init__(self, *args, **kwargs)
          self.target_node = kwargs.get("target", None)
       
     def onKeypressedEvent(self, event):
        if event["key"] == Key.P:
              self.target_node.setActive(False)
        elif event["key"] == Key.B:    
              self.target_node.setSleeping(False)              
        elif event["key"] == Key.A:
              self.target_node.removeObject(self.target_node.child2.position)
          
def createScene(root):
    root.addChild("child1")
    root.child1.addObject("MechanicalObject")
    
    root.child1.addChild("child2")
    root.child1.child2.addObject("MechanicalObject", name="position")
    
    root.addObject(MyController(name="PauseScene", target=root.child1))    

[zbounik]

Hi @damienmarchal,
This is very nice. Thank you.