vcSweptVolume

vcSweptVolume is a layout item used to measure and simulate volume displacement of moving objects and detect collisions.

See in: Overview

Module: vcCore

Parent: vcLayoutItem

Children -

Referenced by: -

Properties

Learn how to use properties here. The properties are also inherited from the parent class.

Name	Type	Access	Description
Decomposition	vcSweptVolumeDecompositionType	RW	Gets or sets how many convex hulls created from included nodes. See more For example one convex hull encompassing all nodes or several convex hulls based on geometry of each node.
DecompositionDecimationTarget	Integer	RW	Gets or sets the target count for decimated triangle sets. See more If Decomposition set to vcSweptVolumeDecompositionType.DECOMPOSITION, sets the number of triangle sets remaining after decimation process of input nodes with fewer triangle sets than decimation target, thereby allowing you to expedite/speed up the process. Set to zero to have no effect.
DecompositionQuality	Real	RW	Gets or sets the quality target for decomposed mesh. See more If Decomposition set to vcSweptVolumeDecompositionType.DECOMPOSITION, sets the quality of decomposition in range 0 to 100, thereby affecting the approximation of convex hulls to the shape of input node geometry. A higher value produces better approximation and convex-shaped triangle sets at the cost of increasing a component's data count and simulation performance.
InputNodeList	list	RW	Gets or sets the simulation nodes based on which the swept volume is created. See more The list and its contents are returned and assigned as a copies. Assign this property to apply any changes.
Material	vcMaterial	RW	Gets or sets the overall material applied to generated swept geometry. When set, this material overrides per-hull default materials for the stored volume result.
Method	vcSweptVolumeMethod	RW	Gets or sets the method used for generating convex hulls as swept geometry, for example hollow or filled convex hulls. Note: Each method type has about the same performance level.
TargetNode	vcNode	RW	Gets or sets the node used for containing swept geometry, which should be static and not move during simulation.

Methods

Learn how to use methods here. The methods are also inherited from the parent class.

Name	Return Type	Parameters	Description
begin	None	Optional Keyword[center = vcVector]	Starts swept volume process, thereby initiating decomposition. See more Parameters: center (vcVector): Defines a frame of reference or center point in input node. If omitted, process uses center point of input node bound box. Exceptions: RuntimeError: When TargetNode or InputNodeList have incorrect values.
clear	None	None	Removes all swept geometry of layout item from 3D world.
end	None	None	Stops swept volume process. After swept volume process has ended, you can perform capping of swept geometry. Exceptions: RuntimeError: When TargetNode or InputNodeList have incorrect values.
next	None	Optional Keyword[center = vcVector]	Executes an iterative process that renders swept geometry based on positions of input nodes. See more That is, you should call this method each time you want to render swept volume in 3D world during swept process. Parameters: center (vcVector): Defines a frame of reference or center point in input node as it moves during a simulation. If omitted, process uses center point of input node bound box. Generally, this is used to offset swept geometry. Exceptions: RuntimeError: When TargetNode is None.
store	vcFeature	None	Stores swept geometry in TargetNode, thereby allowing you to save swept geometry in component and/or layout. See more Generally, you should call store() method after calling end() method and before clear() method. Returns: vcFeature: The Geometry feature where swept volume is stored in TargetNode. The naming convention for feature is VC_SweptVolumeResult, and the feature is an immediate child of TargetNode root feature. None if no swept geometry has been generated. Exceptions: RuntimeError: When TargetNode is None.

Example: Basic Swept Volume

import vcCore as vc

comp = vc.getComponent()
world = vc.getWorld()
sv = None


def start_sweep():
  """Initializes and returns a swept volume layout item"""
  #Create swept volume object
  sv = world.findLayoutItem('swept')
  if sv is None:
    sv = world.createLayoutItem(vc.vcLayoutItemType.SWEPT_VOLUME)
    sv.Name = 'swept'
  #Setup nodes to include/exclude in node list and scope
  target_name = "Sanding Tool"
  nodes = comp.findNode(target_name)
  if nodes is None:
    print("Failed to find node with name: {}".format(target_name))
    return None
  entry = vc.vcNodeListEntry.new()
  entry.Node = nodes
  entry.Type = vc.vcNodeListEntryType.INCLUDE
  entry.Scope = vc.vcNodeListEntryScope.NODE
  sv.InputNodeList = [entry] #List of vcNodeListEntires
  #Set Decomposition and Method
  sv.Decomposition = vc.vcSweptVolumeDecompositionType.CONVEXHULL  # DECOMPOSITION | CONVEXHULL | CONVEXHULL_TRIMESH
  sv.Method = vc.vcSweptVolumeMethod.HULL_FROM_HULLS_V2 # LOFTING, HULL_FROM_HULLS, HULL_FROM_SILHOUETTES, HULL_FROM_HULLS_V2
  #Define container of swept volume geometry (must be static/not move)
  sv.TargetNode = comp
  return sv


async def OnRun():
  """Executed when the simulation is running"""
  global sv
  sv = start_sweep()
  if sv is None:
    return
  sv.begin()
  while True:
    sv.next()
    await vc.delay(0.05) #Defines how often the swept volume is updated


def OnStop():
  """Stop updating the swept volume when the simulation is stopped"""
  if sv is not None:
    sv.end()
 

def OnReset():
  """Remove swept volume as needed. Note that the generated swept volume is parented to target node"""
  if sv is not None:
    sv.clear()

Example: Robot Tool Swept Volume

import vcCore as vc

comp = vc.getComponent()
world = vc.getWorld()
sim = vc.getSimulation()


finalized = False
sweptdefinition = None


def OnFinalize():
  """Triggered when the component is loaded/initialized. Initializes the swept volume"""
  global follownode, boundcenter, sweptdefinition, finalized
  if finalized:
    return
  # Change the name of the node according to your model
  target_name = "Sanding Tool"
  follownode = world.findComponent(target_name)
  if follownode is None:
    print("Failed to find node with name: {}".format(target_name))
    return
  boundcenter = follownode.BoundingBox.Center
  # You may also want to change the name of the layout item.
  # Keep it specific in case you have multiple items
  sweptdefinition = world.findLayoutItem("PressGripperSweptDefintion")
  if(sweptdefinition):
    sweptdefinition.delete()
  sweptdefinition = world.createLayoutItem(vc.vcLayoutItemType.SWEPT_VOLUME)
  sweptdefinition.Name = "PressGripperSweptDefintion"
  # The following entry includes only the target node to be included
  entry = vc.vcNodeListEntry.new()
  entry.Node = follownode
  entry.Type = vc.vcNodeListEntryType.INCLUDE
  entry.Scope = vc.vcNodeListEntryScope.NODE
  sweptdefinition.InputNodeList = [entry] #List of vcNodeListEntires
  # Create a node in component to consist of the swept volume only.
  # This is handy when defining collision queues
  sweptnode = comp.findNode('Swept')
  if not sweptnode:
    sweptnode = comp.createLink('Swept')
  sweptdefinition.TargetNode = sweptnode
  # This is the fastest combination of method and decomposition to generate swept volume
  sweptdefinition.Decomposition = vc.vcSweptVolumeDecompositionType.CONVEXHULL # DECOMPOSITION | CONVEXHULL | CONVEXHULL_TRIMESH
  sweptdefinition.Method = vc.vcSweptVolumeMethod.HULL_FROM_HULLS # LOFTING, HULL_FROM_HULLS, HULL_FROM_SILHOUETTES, HULL_FROM_HULLS_V2
  finalized = True
 
  
def OnReset():
  """Triggered when the simulation is reset. Tell the Swept Definition to clear recording"""
  if sweptdefinition:
    sweptdefinition.clear()
 

def OnStart():
  """Tell the Swept Definition to start recording"""
  OnFinalize()
  sweptdefinition.begin(follownode.WorldPositionMatrix * boundcenter)
 

def OnSimulationUpdate(time):
  """Tell the Swept Definition to record one step"""
  if finalized and sim.IsRunning:
    sweptdefinition.next(follownode.WorldPositionMatrix * boundcenter)
 

def OnStop():
  """Tell the Swept Definition to stop recording"""
  if sweptdefinition:
    sweptdefinition.end()