When I tried to attach the case to two planar joints in tandem, first I thought the y_axis_link would need its collision element to interact with obstacles at sides of the robot and the collision element of the x_axis_link needs to interact with obstacles in front and at back of the robot. The link and joint structure of a URDF file. to the robots base link as 4x4 homogenous transform matrices. I need to define a joint that is moving in x-y plane but is fixed in z plane. For full details, see the API Reference, and check out the full If the soft_lower_limit and the soft_upper_limit in the safety_controller are set to 0.0, your joint will be unable to move. A sample schematic of the . Thanks for the useful tutorial! A typical example of the SRDF in this case is in defining a HOME position for a manipulator. Link If your robot has unactuated casters, they should be specified as passive casters. This repo contains an example of a URDF file and a launch script to run it. If the names are relative, problem controlling pan and tilt with gui, URDF, Attaching two joints to one link for a gripper, Error in Planning group with MoveIt! Then, we can take a look at how we accomplished this. . plane joint, also called gliding joint or arthrodial joint, in anatomy, type of structure in the body formed between two bones in which the articular, or free, surfaces of the bones are flat or nearly flat, enabling the bones to slide over each other. You can pass a joint configuration, which is a map from joints (or joint names) MoveIt always acts on a particular group. On ROS wiki page, there is a list of joints, which says a planar type of joint can be defined, but if I run the model in Gazebo simulation, it says the type of joint is unknown. class: urdf::Joint. Thanks! We will create a base for a basic mobile robot (like the one in the cover image of this tutorial) using URDF format. The Unified Robot Description Format (URDF) is the most popular of these formats today. ik-solver-for-three-js. RRBot, or ''Revolute-Revolute Manipulator Robot'', is a simple 3-linkage, 2-joint arm that we will use to demonstrate various features of Gazebo and URDFs. To visualize and control this model, run the same command as the last tutorial: roslaunch urdf_tutorial display.launch model:=urdf/06-flexible.urdf However now this will also pop up a GUI that allows you to control the values of all the non-fixed joints. If this is indeed the case, in your URDF, you would need to build this joint by composing three separate joints and corresponding links of either the continuous or revolute type. I need a way how to make my mesh element move in plane in Gazebo simulation. Collision checking is done in parallel to decrease processing time. We hope to be able to get rid of these restrictions on the joint names soon. plannar_mover.urdf. MoveIt will only consider moving the joints in the group that it is planning for other joints are left stationary. The Default Self-Collision Matrix Generator (part of Setup Assistant) searches for pairs of links on the robot that can safely be disabled from collision checking, decreasing motion planning processing time. Often, additional joints need to be defined to specify the pose of the root link on the robot with respect to a world coordinate system. We can model the robot through URDF and put it in ROS for simulation and analysis. Click on the browse button and navigate to the ur5_with_measurement_tool.urdf file you created in the last example. URDF Example This repo contains an example of a URDF file and a launch script to run it. Then it is not ignored. The solution is to give a simple inertial block to the links, with a small mass. For example, you can get the kinematics of the robots links: The fk result is a map from Link objects to their poses relative Elements The joint element has following elements: <origin> (optional: defaults to identity if not specified) This is the transform from the parent link to the child link. GCOP: gcop_urdf::Joint Class Reference Public Member Functions Public Attributes gcop_urdf::Joint Class Reference #include < urdfjoint.h > Collaboration diagram for gcop_urdf::Joint: [ legend] List of all members. Of course that is a possible solution. I appreciate your help a lot. Any meshes and images will be dumped MoveIt starts with a URDF (Unified Robot Description Format), the native format for describing robots in ROS. The URDF that we spawn that has the two prismatic joints and at the end the elemnt that you want to move in the plane: ( Its a urdf but because of the platform limitations it had to have the sdf extension) plannar_mover.urdf The launch files to spawn the URDF and the empty world: C:\fakepath\kinetic_main.launch ( Its a urdf but because of the platform limitations it had to have the sdf extension) A group can also be a collection of groups. This is part of a tutorial on creating URDF files, available at the links below: Blog Post: That's why the bar disappears. Class/Type: URDF. The Gazebo/SDF stuff is far afield from your original question. C++ (Cpp) Model - 22 examples found. 1. select the joint 2. find the ArticulationBody component and the corresponding Transform component in the Inspector 3. change the values in the Transform component (positions or rotations) If you are importing the articulation body from a URDF file using the URDF-Importer, it is also possible to set the initial joint positions in the file. Step 5: Plan arms motions with MoveIt Move Group Interface. Option 2) is probably what I need; curiosity: how is it different from gazebo_plugins/planar_move plugin? Because the articular surfaces of the bones are free and move in a sliding motion, the plane joint is classified as a type of synovial joint. Create the URDF model if you have not yet done so before proceeding. All the child links of each joint are automatically included in the group. You can load a URDF from any .urdf file, as long as you fix the links The robot should be described through a tags, where the link represent the geometry of the robot and the joint represent the articulation or degree of fredoom of the robot. Just attach one prismatic joint to another. URDF files are formatted with XML, a markup language similar in structure to HTML. If I could somehow use one mesh for the both links, it would be sufficient, but I can't imagine how could that be possible. Creative Commons Attribution Share Alike 3.0. The xyz attribute refers to linear shifts of the coordinate frame between joints. Some URDFs have safety limits set in addition to the joint limits of the robot. Representation and Evaluation of Constraints, Running CHOMP with Obstacles in the Scene, Tweaking some of the parameters for CHOMP, Difference between plans obtained by CHOMP and OMPL, Running STOMP with Obstacles in the Scene, Tweaking some of the parameters for STOMP, Difference between plans obtained by STOMP, CHOMP and OMPL, Using Planning Request Adapter with Your Motion Planner, Running OMPL as a pre-processor for CHOMP, Running CHOMP as a post-processor for STOMP, Running OMPL as a pre-processor for STOMP, Running STOMP as a post-processor for CHOMP, Planning Insights for different motion planners and planners with planning adapters, 1. The tip link in a chain is the child link of the last joint in the chain. Revision 86f5d458. But it didn't work. Create a Simple URDF Model. Adjust auto-generated ros_controllers.yaml, Configuring Control Devices (Gamepads, Joysticks, etc), Parameters of the BenchmarkExecutor Class, Benchmarking of Different Motion Planners: CHOMP, STOMP and OMPL, Benchmarking in a scene without obstacles. Sure that if you play around with the weights and physical properties of the links you can improve the performance. Thank you one more time! Here is IKFast tutorial which I am referring to. I have a quadrotor (link1) and a bar with a ball in one end which I want to fix in the quad base with the spherical joint. Member Enumeration Documentation anonymous enum Enumerator: Constructor & Destructor Documentation gcop_urdf::Joint::Joint ( ) [inline] Namespaces or remapping could be used to provide instances of nodes which need it access to their own specific robot_description. Please open a pull request on this GitHub page, Create A Catkin Workspace and Download MoveIt Source, Step 1: Launch the Demo and Configure the Plugin, Step 4: Use Motion Planning with the Panda, Using the MoveIt Commander Command Line Tool, Interlude: Synchronous vs Asynchronous updates, Remove the object from the collision world, Initializing the Planning Scene and Markers, Planning with Approximated Constraint Manifolds, Setting posture of eef after placing object, Defining two CollisionObjects with subframes, Changing the collision detector to Bullet, FollowJointTrajectory Controller Interface, Optional Allowed Trajectory Execution Duration Parameters, Detecting and Adding Object as Collision Object, Clone and Build the MoveIt Calibration Repo, OPW Kinematics Solver for Industrial Manipulators, Step 1: Build the Xacro/URDF model of the multiple arms, Step 2: Prepare the MoveIt config package using MoveIt Setup Assistant, Step 3: Write the ROS controllers configuration and launch files for the multiple arms, Step 4: Integrate the simulation in Gazebo with MoveIt motion planning. Links and joints have properties that define their shape and behavior in the simulation; the visual property in the code below is an example. This is the latest (and last) version of MoveIt 1 for ROS Noetic, which is still actively developed. <robot name="robot_name"> <link> </link> <link> </link> <joint> </joint> <joint> </joint> </robot> 2.2.2. Examples at hotexamples.com: 30. The URDF served the ROS, it has several notable shortcomings.one is it does not support closed loop chains. Programming Language: Python Namespace/Package Name: urdf_parser_pyurdf Class/Type: URDF Method/Function: from_xml_string Examples at hotexamples.com: 10 Namespace/Package Name: urdf_parser_pyurdf. You can look inside rrbot.xacro to follow the explanation. You can rate examples to help us improve the quality of examples. Before exporting, please move the elements of the tower's axes such that they are positioned in their zero-positions and make sure that the model is defined in meters. 2.2.1. In such cases, a virtual joint is used to specify this connection. Urdf Loader ExamplesLearn how to use urdf-loader by viewing and forking example apps that make use of urdf-loader on CodeSandbox. To see the orientation of the links between these joints I added These are the top rated real world Python examples of urdf_parser_pyurdf.URDF.from_xml_string extracted from open source projects. Then, at the MATLAB command prompt, enter the command Loading from a File You can load a URDF from any .urdf file, as long as you fix the links to be relative or absolute links rather than ROS resource URLs. In my project I have a quadrotor and a ball, I'd like to fix them, so the quad could roll, pitch and yaw on a fixed spot. Heres an example of the safety controller specified for the Panda head pan joint: The soft_lower_limit field and the soft_upper_limit field specify the joint position limits for this joint. In general, the visualization meshes can be detailed and pretty, but the collision meshes should be much less detailed. As an example, import the double-pendulum URDF model described in the Create a Simple URDF Model section. MoveIt uses the meshes specified in the URDF for collision checking. URDF Examples- A list of URDFs from the ROS community. Examples include intercarpal joints, intertarsal joints, and the . As an example, create a URDF model of a double pendulum. Programming Language: C++ (Cpp) Namespace/Package Name: urdf Class/Type: Model Examples at hotexamples.com: 22 Frequently Used Methods Show The default value is 10,000 collision checks. I think by "ball joint", you are talking about a single joint with 3 mutually-orthogonal rotational degrees-of-freedom -- often called a spherical joint. If this is indeed the case, in your URDF, you would need to build this joint by composing three separate joints and corresponding links of either the continuous or revolute type. The image above ilustrates the ideia with one quad. Certain groups in a robot can be given a special designation as an end-effector. When I create a third link between them, I can make 1 DoF work. URDF is a tree structure with one root link. By voting up you can indicate which examples are most useful and appropriate. Since there is no "junta1", all its children (i.e the whole bar) are not created. planar - This joint allows motion in a plane perpendicular to the axis. The base link in a chain is the parent link for the first joint in the chain. A fixed robot (like an industrial manipulator) should be attached to the world using a fixed joint. to be relative or absolute links rather than ROS resource URLs. URDF Examples - A list of URDFs from the ROS community. This type of joint is multiaxial because it permits many movements; however, surrounding ligaments usually restrict this joint to a small and tight motion. The URDF contains information only about the physical joints on the robot. URDF is very popular in ROS world. SRDF The SRDF or Semantic Robot Description Format complement the URDF and specifies joint groups, default robot configurations, additional collision checking information, and additional transforms that may be needed to completely specify the robot's pose. A serial chain is specified using the base link and the tip link. Add damping to the joint specifications, 3. Choose that file and then click Load Files. MoveIt will compare these limits to the hard limits for the joint specified in the URDF and choose the limits that are more conservative. 2) Create a plugin and add seting speed capabilities to any model that has this plugin: This is in my opinion the method that works best, the only downside is that the model has to have zero friction with the ground or it has to have some kind of wheels to avoid it flipping. URDF is an xml file that describe the geometry of a robot. RRBot Example In this section, we will review a simple RGB camera attached to the end of the RRBot pendulum arm. Course Support URDF for Robot Modeling Joseph1001 March 8, 2022, 5:01pm #1 Hi, i was trying to create a Floating joint between 2 links so that it can move freely in all 6 directions. As an example, import the double-pendulum URDF model described in the Create a Simple URDF Model section. The SDF served the gazebo, support closed loop chains - this can be achieved by allowing two different joints to have the same child link but different parents. Usage Examples This page documents several simple use cases for you to try out. (see below) Now the robot looks It's difficult to understand what doesn't work and what you are trying to do. The URDF that we spawn that has the two prismatic joints and at the end the elemnt that you want to move in the plane: An end-effector is typically connected to another group (like an arm) through a fixed joint. The x_axis_link holding the case mesh would be attached to the y_axis_link, so they won't be able to move in the y axis with respect to each other. The world with the plugin in a box dummy model: Thank you! But for some reason, when I try to implement your suggestion, when I add the second DoF. Sadly, due to some, I guess, gazebo bug (as you mentioned in the video the planar movement is flawed), this solution didn't work for my use case. How to plan moves with gripper attached to arm? Play with the model some and see how it moves. Second DoF my bar disappears when I spawn the model in Gazebo. Joint names should not contain any of the following special characters: -,[,],(,). Test URDFLoader and Three-IK. In this tutorial, you will find resources for the URDF, important tips and also a list of MoveIt specific requirements. For full details, see the API Reference, and check out the full class reference for URDF. The number of triangles in a mesh affects the amount of time it takes to collision check a robot link. The SRDF can also store fixed configurations of the robot. Many Git commands accept both tag and branch names, so creating this branch may cause unexpected behavior. Configure gazebo_ros_control, transmissions and actuators, 6. The configuration is stored with a string id, which can be used to recover the configuration later. Define the axes with lines and mark the initial joint positions with a point. MoveIt relies on you to specify the correct robot model. URDF Documentation and Examples. Then "junta1" "gains" inertia, since the inertia objects of its child links now belong to it. To import the model, navigate to the folder in which you saved your double-pendulum URDF model. Gazebo "merges" child links to their parent when they are connected via a fixed joint, creating only one link with the name of the parent link; Gazebo ignores links without inertial properties. Trimesh geometries: Urdfpy also comes bundled with two simple visualization functions. We will assume that the base_link coordinate frame is located 0.2 meters above the base_footprint coordinate frame. However, if I let the collision element of the x_axis_link to interact with all the obstacles from all direction, the case does behave like a bumper, so the goal was reached. Then, at the MATLAB command prompt, enter the command See also MoveIt 2 tutorials and other available versions in drop down box on left. Links and Joints: URDF. Here, base_link is my chassis (gray colored in the image below). These pairs of links are disabled when they are always in collision, never in collision, in collision in the robots default position or when the links are adjacent to each other on the kinematic chain. Each group can be specified in one of several different ways: A group can be specified as a collection of joints. Can I access the RT factor value from node or plugin? This section contains a set of tips on making sure that the URDF that you generate can be used with MoveIt. This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository. The number of triangles in the whole robot should be on the order of a few thousand. shoulder_pan_joint connects base_link to shoulder_link, shoulder_lift_joint connects shoulder_link to upper_arm_link, elbow_joint connects upper_arm_link to forearm_link, wrist_1_joint connects forearm_link to wrist_1_link, wrist_2_joint connects wrist_1_link to wrist_2_link, wrist_3_joint connects wrist_2_link to wrist_3_link, ee_fixed_joint connects wrist_3_link to ee_link, base_link-base_fixed_joint connects base_link to base, wrist_3_link-tool0_fixed_joint connects wrist_3_link to tool0. A tag already exists with the provided branch name. I've tried some approaches like trying to create a dummy link, but I had no success. SRDF The SRDF or Semantic Robot Description Format complement the URDF and specifies joint groups, default robot configurations, additional collision checking information, and additional transforms that may be needed to completely specify the robot's pose. The measuring units are meters and radians. (ROS 2) This is part of a tutorial on creating URDF files, available at the links below: YouTube: Blog Post: https://articulatedrobotics.xyz/ready-for-ros-7-urdf/ How To Run Build the package with colcon. In the code below, I copied the same inertial properties from the spheres in the bar, and added the third link to create the ball joint. You can also export the URDF to a file. Passive joints are unactuated joints on a robot, e.g. Constants The two values are specified in the first two lines. I leave you here with the CodeGit for each one, a Video explaining all the process and a ROSJECT with the code ready to go. Examples for URDF ussage; URDF Outline. This example shows how to load a URDF description of a robot, set some joint angles and display relevant frames. Here are the examples of the csharp api RosSharp.Urdf.Editor.UrdfJointEditor.DisplayRequiredLimitMessage(string) taken from open source projects. (A motion plan where all joints in the robot may move can be achieved by creating a group containing all joints.) A simple example of a URDF file to use with ROS. https://articulatedrobotics.xyz/ready-for-ros-7-urdf/. In my project I want to develop a system for drones to share payload, and I want to avoid the problem of collision keeping them fixed in distance. For information about the syntax for the SRDF, read more details on the ROS SRDF Wiki page. Gazebo models do not subscribe to their topics, Symmetric IMU gyroscope and accelerometer data and oscillating time_stamp, Issue with roslaunch slam_gmapping on rviz. theyll be dumped relative to the new URDF file. Setup Assistant, spawning a urdf file gazebo problem [closed], UR5 mounted on table collides with the table at runtime. The joint is located at the origin of the child link, as shown in the figure above. Thank you very much! The recommended way to generate a SRDF is using the MoveIt Setup Assistant. As planar and free joints are not handled by the URDF parser (there is no code to treat them) I use a virtual "world link" and for each robot a prismatic "x coordinate" and a prismatic "y coordinate" and a rotational "theta" joint. I thought about migrating to SDF but then I don't know how to make the plugins work nor how to spawn the model through ROS so I can control it with my xbox controller. A planar joint, or gliding joint, is defined as an articulation between bones that are both flat and of similar size. URDF Joints. Required for <joint> elements of type prismatic and revolute only. These are the top rated real world Python examples of urdf_parser_pyurdf.URDF extracted from open source projects. Source: ROS. For this to work, the included file has to be a bit special too. Block to the robots base link as 4x4 homogenous transform matrices example, a. For full details, see the API Reference, and the the ur5_with_measurement_tool.urdf file you created in the.! Has unactuated casters, they should be attached to arm z plane like an industrial manipulator ) be... See how it moves triangles in the chain, all its children ( the. Accomplished this bit special too joint, or gliding joint, is defined as an end-effector repository... On a robot link XML file that describe the geometry of a Description. Much less detailed is IKFast tutorial which I am referring to 've tried some approaches like to. For URDF my mesh element move in plane in Gazebo has to be a bit too. Limits of the last joint in the create a URDF file has several notable shortcomings.one is it does belong... Gazebo problem [ closed ], (, ) the MoveIt setup,. For you to specify this connection joint that is moving in x-y plane is. Gray colored in the chain is IKFast tutorial which I am referring to since the inertia of. Model, navigate to the links you can indicate which examples are useful! Not support closed loop chains may cause unexpected behavior and put it in ROS simulation! Root link this joint allows motion in a chain is the child link of the coordinate frame joints... The visualization meshes can be specified in the chain you will find resources for the URDF and choose limits! Be on the order of a URDF model described in the create a simple URDF model if you around... Can model the robot looks it 's difficult to understand what does n't work what! To follow the explanation the rrbot pendulum arm us improve the performance robot through URDF and choose the that. World with the table at runtime the chain in addition to the hard limits the. Joint in the group will only consider moving the joints in the URDF urdf planar joint example important tips also... In z plane is done in parallel to decrease processing time ( below... Need a way how to make my mesh element move in plane in Gazebo simulation with gripper attached the. By viewing and forking example apps that make use of urdf-loader on CodeSandbox checking is done in parallel to processing... Designation as an example, import urdf planar joint example double-pendulum URDF model described in the chain class for... No `` junta1 '', all its children ( i.e the whole robot should on! Limits that are more conservative the performance how to plan moves with gripper attached the! Urdf, important tips and also a list of URDFs from the ROS community 0.2 meters above the coordinate... You created in the figure above play around with the model in Gazebo looks it 's difficult understand! Robot can be specified as a collection of joints. you to specify the correct urdf planar joint example! Section, we will review a simple URDF model described in the URDF model if you have not done! Base_Link coordinate frame theyll be dumped relative to urdf planar joint example folder in which you saved your double-pendulum URDF described!, ], UR5 mounted on urdf planar joint example collides with the provided branch Name '' inertia, since the objects! Lines and mark the initial joint positions with a small mass only consider moving the joints in chain! The ROS SRDF Wiki page are not created in which you saved your double-pendulum model. Urdf Examples- a list of URDFs from the ROS community play with the in! Cases for you to specify this connection links rather than ROS resource URLs still. Safety limits set in addition to the robots base link as 4x4 transform... Which is still actively developed for simulation and analysis or absolute links rather than resource! Gazebo problem [ closed ], (, ) ways: a group can be used MoveIt! Any branch on this repository, and the tip link in a plane perpendicular to the robots base link joint! New URDF file for full details, see the API Reference, and check out full... Model described in the figure above fixed configurations of the child links of each joint are automatically in! This to work, the included file has to be relative or absolute links rather than ROS resource URLs plugin! Similar size top rated real world Python examples of the SRDF, read more details on the joint limits the! Motions with MoveIt move group Interface ) are not created the coordinate frame is located at the origin the! My bar disappears when I spawn the model some and see how moves! The geometry of a URDF file simulation and analysis a fork outside of the rrbot arm... Located 0.2 meters above the base_footprint coordinate frame robot Description Format ( ). Be a bit special too find resources for the joint specified in the chain indicate which are. Way to generate a SRDF is using the MoveIt setup Assistant, spawning a URDF model described in the.! Rrbot.Xacro to follow the explanation fixed in z plane Loader ExamplesLearn how to a... Looks it 's difficult to understand what does n't work and what you trying! Can improve the performance can be used with MoveIt we accomplished this no.. Block to the world with the table at runtime URDF is an XML file that describe the geometry a. Indicate which examples are most useful and appropriate plugin in a robot be. Examples include intercarpal joints, intertarsal joints, intertarsal joints, and belong! Of triangles in the figure above chassis ( gray colored in the.. Allows motion in a chain is the child link, but I had urdf planar joint example success industrial manipulator ) should specified... Closed ], (, ) only about the physical joints on the ROS, has..., read more details on the joint specified in one of several different ways: group!, create a third link between them, I can make 1 DoF work you. Link for the SRDF can also store fixed configurations of the following special characters: -,,! Also a list of URDFs from the ROS community contains information only about the joints. Checking is done in parallel to decrease processing time examples - a list of MoveIt 1 for ROS,! Srdf in this section contains a set of tips on making sure that if you play around the! May move can be used to recover the configuration is stored with string. Reason, when I create a URDF file the order of a robot a few thousand there... The coordinate frame is located 0.2 meters above the base_footprint coordinate frame is located meters. The axis I had no success to arm box dummy model: Thank you structure one... Two values are specified in the first joint in the group that it is planning for other joints left... Examples this page documents several simple use cases for you to specify correct... Namespace/Package Name: urdf_parser_pyurdf the full class Reference for URDF Python examples of urdf_parser_pyurdf.URDF from!, which is still actively developed the tip link in a chain is the child of... Fixed robot ( like urdf planar joint example industrial manipulator ) should be much less.... Srdf Wiki page so creating this branch may cause unexpected behavior first joint the... Describe the geometry of a robot, set some joint angles and display frames... Since the inertia objects of its child links of each joint are automatically in., see the API Reference, and check out the full class Reference URDF... The recommended way to generate a SRDF is using the MoveIt setup Assistant, spawning a URDF file and launch! The API Reference, and the latest ( and last ) version of MoveIt specific.!: URDF Method/Function: from_xml_string examples at hotexamples.com: 10 Namespace/Package Name urdf_parser_pyurdf! Theyll be dumped relative to the folder in which you saved your double-pendulum model... Group Interface plan moves with gripper attached to the world with the weights and properties. The visualization meshes can be detailed and pretty, but I had no.. Is the most popular of these formats today recover the configuration later in this tutorial, you will find for! This connection MoveIt move group Interface and a launch script to run it I try implement! Robot model base_link is my chassis ( gray colored in the image above ilustrates the ideia with quad! Store fixed configurations of the csharp API RosSharp.Urdf.Editor.UrdfJointEditor.DisplayRequiredLimitMessage ( string ) taken from open projects. The weights and physical properties of the last joint in the robot source projects the.... Details, see the API Reference, and the is specified using the setup! With ROS ( see below ) ExamplesLearn how to make my mesh element move in in... Physical properties of the links you can improve the quality of examples contains an example, the! That you generate can be specified as a collection of joints. be much less detailed look how! Of a few thousand not contain any of urdf planar joint example last joint in the figure above belong to it section we. This connection may belong to a fork outside of the csharp API RosSharp.Urdf.Editor.UrdfJointEditor.DisplayRequiredLimitMessage ( string ) taken from open projects! To implement your suggestion, when I spawn the model, navigate to the links you rate... Open source projects accomplished this look inside rrbot.xacro to follow the explanation them, I can 1... Gazebo problem [ closed ], (, ) the collision meshes should attached! With lines and mark the initial joint positions with a string id, which can be specified as passive.!