Inquiries about puncture

[wkz228]

I tried to use a needle to prick a software block in SOFA, but the software block in the.msh file I imported did not seem to be able to prick, it would show a very abstract deformation. My.msh file was exported using gmsh. However, when I use liver's.msh file in the example, using the same code, the simulation should be punctured normally. I want to know what the problem is, is there a problem with my gmsh export process?

[bakpaul]

Hello !

I am sorry but without the scene file I cannot do anything for you.

[wkz228]

As described in the code above. I built a needle and a needle control module in sofa, needle is rigid body. The purpose is to interact with the needle and the imported liver model. However, in the process of running this code, abnormal liver deformation occurred during interaction. I would like to know how to solve this problem. Thank you for your answer!

def Needle(parentNode=None, name="Needle",
           rotation=[0.0, 0.0, 0.0], translation=[20, 30, 15]):
    needleNode = parentNode.addChild(name)

    meshLoader = needleNode.addObject("MeshSTLLoader", name="MeshLoader",
                                      filename="/home/wan/livernew/model/livernew/liver_model_blender/tool2.stl")

    mechanicalObject = needleNode.addObject("MechanicalObject",
                                            template="Rigid3d",
                                            position=[
                                                [translation[0], translation[1], translation[2], 0.0, 0.0, 0.0, 1.0]])

    RigidObject(parent=needleNode,
                totalMass=0.032,
                rotation=rotation,
                translation=translation,
                color=[1.0, 0.0, 0.0, 1.0])

    visualModel = needleNode.addObject("OglModel", name="VisualModel", src="@MeshLoader", color=[1.0, 0.0, 0.0, 1.0])
    needleNode.addObject("RigidMapping", input="@MechanicalObject", output="@VisualModel")

    collisionModel = needleNode.addChild("Collision")
    collisionModel.addObject("MeshTopology", src="@../MeshLoader")
    collisionModel.addObject("MechanicalObject", name="CollisionMechanical")
    collisionModel.addObject("TriangleCollisionModel")
    collisionModel.addObject("LineCollisionModel")
    collisionModel.addObject("PointCollisionModel")
    collisionModel.addObject("RigidMapping", input="@../MechanicalObject", output="@CollisionMechanical")

    return needleNode
#This is the definition of the needle.

class RigidController(Controller):
    def __init__(self, needle, target_position, tolerance=0.01, speed_factor=0.02):
        Controller.__init__(self)
        self.needle_node = needle
        self.needle = needle.getObject("MechanicalObject")
        self.target_position = target_position
        self.tolerance = tolerance
        self.speed_factor = speed_factor
        self.is_moving = True

    def onAnimateBeginEvent(self, event):
        if self.is_moving:
            positions = self.needle.findData("position").value
            current_position = positions[0][:3]

            distance = [
                self.target_position[i] - current_position[i] for i in range(3)
            ]
            distance_magnitude = sum(d ** 2 for d in distance) ** 0.5

            if distance_magnitude <= self.tolerance:
                self.is_moving = False
                print(f"Needle reached target position: {self.target_position}")
                return

            step = [d * self.speed_factor for d in distance]
            updated_positions = positions.copy()
            updated_positions[0][:3] = [
                current_position[i] + step[i] for i in range(3)
            ]
            self.needle.findData("position").value = updated_positions
#This is the definition of the rigid needle, designed to move the rigid needle along a straight line to a specific position and interact with the liver.

[wkz228]

It seems that the code does not define any parameters related to the fracture limit. Do you have any good suggestions? Or are there any methods that can be applied to assign physical parameters similar to the fracture limit when importing the GMSH file?

[hugtalbot]

Hi @wkz228

The example of Cosserat allow to define a threshold on the insertion force in a dedicated script : https://github.com/SofaDefrost/Cosserat/blob/master/examples/python3/cosserat/needle/needleController.py#L28

[wkz228]

i will try it. Thank you for your reply!

[hugtalbot]

Keep us posted