Can you provide a demo rendering urdf file?

[williamlzw]

I am doing robot simulation and plan to do simulation based on jitterphysics2. I am not familiar with physics engines and don't know how to use jitterphysics2 to write joint code in urdf. Can you provide a demonstration of joint motion in urdf and render it?
The following is the urdf path:
https://github.com/unitreerobotics/unitree_rl_gym/blob/main/resources/robots/go2/urdf/go2.urdf
The mesh is in .dae format, how to render it?

[williamlzw]

This is the reference code for reading urdf files:
https://github.com/siemens/ros-sharp/tree/master/Libraries/Urdf

[notgiven688]

This looks like an interesting project—creating a demo that reads URDF files! The format seems fairly simple, so this could be a great way to get familiar with both JitterPhysics2 and URDF. You might want to start by parsing the file structure and identifying the joints. If you run into specific issues with integrating JitterPhysics2, feel free to ask! I'm converting this to a discussion since it's more of an exploration rather than a bug or missing feature in the engine.

[williamlzw]

<joint
    name="Head_upper_joint"
    type="fixed" dont_collapse="true">
    <origin
      xyz="0.285 0 0.01"
      rpy="0 0 0" />
    <parent
      link="base" />
    <child
      link="Head_upper" />
    <axis
      xyz="0 0 0" />
  </joint>

<joint
    name="FL_hip_joint"
    type="revolute">
    <origin
      xyz="0.1934 0.0465 0"
      rpy="0 0 0" />
    <parent
      link="base" />
    <child
      link="FL_hip" />
    <axis
      xyz="1 0 0" />
    <limit
      lower="-1.0472"
      upper="1.0472"
      effort="23.7"
      velocity="30.1" />
  </joint>

How to define these two types of joints using jitterphysics2?

[williamlzw]

<link
    name="RL_foot">
    <inertial>
      <origin
        xyz="0 0 0"
        rpy="0 0 0" />
      <mass
        value="0.04" />
      <inertia
        ixx="9.6e-06"
        ixy="0"
        ixz="0"
        iyy="9.6e-06"
        iyz="0"
        izz="9.6e-06" />
    </inertial>
    <visual>
      <origin
        xyz="0 0 0"
        rpy="0 0 0" />
      <geometry>
        <mesh
          filename="../dae/foot.dae" />
      </geometry>
      <material
        name="">
        <color
          rgba="1 1 1 1" />
      </material>
    </visual>
    <collision>
      <origin rpy="0 0 0" xyz="-0.002 0 0" />
      <geometry>
        <sphere radius="0.022" />
      </geometry>
    </collision>
  </link>

How to render such a link node?