Best Practices

To get the most out of LinkForge and ensure your robot simulations are stable and professional, follow these best practices.

Modeling for Physics

Physics engines like Gazebo or Bullet are highly sensitive to how geometry and mass are defined.

1. Scale and Units

  • Always use Meters: Blender can use various units, but ROS and URDF expect Meters. LinkForge automatically handles basic conversions, but modeling at a 1:1 scale in meters is the safest approach.

  • Apply Scale: Before creating links or joints, ensure all objects have an applied scale of (1, 1, 1). Select objects and press Ctrl+A > Scale.

2. Mesh Simplification

  • Collision vs. Visual: Use high-poly meshes for visuals, but always use simplified primitive shapes (Box, Cylinder, Sphere) for colliders. LinkForge allows you to set a primitive as the collision shape for a complex visual mesh.

  • Avoid β€œThin” Colliders: Very thin meshes (like a piece of paper) can cause tunneling errors in physics engines. Give your colliders some thickness.

3. Orientation

  • X-Forward, Z-Up: LinkForge uses direct 1:1 coordinate mapping (no automatic rotations). Following the ROS standard (X-axis forward, Y-axis left, Z-axis up) when modeling your robot in Blender will make joint configuration intuitive and match ROS expectations.

  • Root Base Link Origin: To comply with URDF kinematics standards, LinkForge automatically treats the root base link as the center of the local coordinate system (0, 0, 0). Any global translation or rotation applied to the root base link in Blender will be stripped upon export. You should position your robot wherever it is easiest to model in Blender, and spawn it at the desired world coordinates dynamically inside your simulator.

Modular XACRO Design

If you are building a complex robot (e.g., a quadruped or a high-DOF arm), modularity is key.

Use Macros for Repetition

Instead of defining 4 identical leg links manually, use LinkForge’s XACRO Export settings to group identical meshes.

Separation of Concerns

Consider organizing your robot into:

  • robot.xacro: The main assembly file.

  • materials.xacro: Centralized material definitions to ensure consistent colors.

  • constants.xacro: Store common values like PID gains or sensor offsets.

Performance Tips

Limit High-Quality Mesh Usage

Too many high-resolution meshes in a simulation will drop the Real-Time Factor (RTF). Use the Decimate Modifier in Blender to reduce triangle counts for your visual meshes before export.

Sensor Update Rates

Don’t set sensor update rates higher than necessary. A 100Hz LiDAR might be overkill for a slow-moving mobile robot and will consume unnecessary CPU cycles.

Control Configuration

Prefer Centralized Control

Use the centralized Control Dashboard to manage all joint interfaces. It provides a single view of all hardware configurations and ensures your ros2_control tags are generated correctly for modern Gazebo/ROS 2 integration.

Data Preservation

Importing Robots

When importing an existing robot (URDF/XACRO), LinkForge automatically disables Auto-Calculate Inertia to preserve your original, scientifically calibrated inertia tensors. Do not re-enable this checkmark unless you have modified the geometry significantly and want LinkForge to re-approximate the physics properties.