Key Engineering Takeaways
- •Never write raw repetitive URDF—use Xacro macros to parameterize wheel diameters, mass properties, and colors.
- •Separate complex visual STL/DAE meshes from simplified convex hull collision geometries (cylinders, boxes) to speed up collision checking 100x.
- •Accurate inertial tensors (ixx, iyy, izz) are strictly mandatory for realistic physics simulation in Gazebo and MuJoCo.
- • XML syntax basics
- • 3D coordinate systems
URDF Anatomy: Links, Joints, Visuals & Collisions
A URDF defines the kinematic tree of a robot consisting of Links (rigid bodies) connected by Joints (revolute, continuous, prismatic, fixed, floating).