> This page is for version Release 2.3. > For other versions, use one of these documentation indexes: > - Release 3.0 (default): https://docs.nvidia.com/isaaclab/3.0/llms.txt > - Release 2.3: https://docs.nvidia.com/isaaclab/2.3/llms.txt > - Release 2.2: https://docs.nvidia.com/isaaclab/2.2/llms.txt > - Release 2.1: https://docs.nvidia.com/isaaclab/2.1/llms.txt > For clean Markdown of any page, append .md to the page URL. > For a complete documentation index, see https://docs.nvidia.com/isaaclab/llms.txt. > For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://docs.nvidia.com/isaaclab/_mcp/server. # Creating Visualization Markers Visualization markers are useful to debug the state of the environment. They can be used to visualize the frames, commands, and other information in the simulation. While Isaac Sim provides its own `isaacsim.util.debug_draw` extension, it is limited to rendering only points, lines and splines. For cases, where you need to render more complex shapes, you can use the `markers.VisualizationMarkers` class. This guide is accompanied by a sample script `markers.py` in the `IsaacLab/scripts/demos` directory. ```python # Copyright (c) 2022-2025, The Isaac Lab Project Developers (https://github.com/isaac-sim/IsaacLab/blob/main/CONTRIBUTORS.md). # All rights reserved. # # SPDX-License-Identifier: BSD-3-Clause """This script demonstrates different types of markers. ~~~bash # Usage ./isaaclab.sh -p scripts/demos/markers.py ~~~ """ """Launch Isaac Sim Simulator first.""" import argparse from isaaclab.app import AppLauncher # add argparse arguments parser = argparse.ArgumentParser(description="This script demonstrates different types of markers.") # append AppLauncher cli args AppLauncher.add_app_launcher_args(parser) # parse the arguments args_cli = parser.parse_args() # launch omniverse app app_launcher = AppLauncher(args_cli) simulation_app = app_launcher.app """Rest everything follows.""" import torch import isaaclab.sim as sim_utils from isaaclab.markers import VisualizationMarkers, VisualizationMarkersCfg from isaaclab.sim import SimulationContext from isaaclab.utils.assets import ISAAC_NUCLEUS_DIR, ISAACLAB_NUCLEUS_DIR from isaaclab.utils.math import quat_from_angle_axis def define_markers() -> VisualizationMarkers: """Define markers with various different shapes.""" marker_cfg = VisualizationMarkersCfg( prim_path="/Visuals/myMarkers", markers={ "frame": sim_utils.UsdFileCfg( usd_path=f"{ISAAC_NUCLEUS_DIR}/Props/UIElements/frame_prim.usd", scale=(0.5, 0.5, 0.5), ), "arrow_x": sim_utils.UsdFileCfg( usd_path=f"{ISAAC_NUCLEUS_DIR}/Props/UIElements/arrow_x.usd", scale=(1.0, 0.5, 0.5), visual_material=sim_utils.PreviewSurfaceCfg(diffuse_color=(0.0, 1.0, 1.0)), ), "cube": sim_utils.CuboidCfg( size=(1.0, 1.0, 1.0), visual_material=sim_utils.PreviewSurfaceCfg(diffuse_color=(1.0, 0.0, 0.0)), ), "sphere": sim_utils.SphereCfg( radius=0.5, visual_material=sim_utils.PreviewSurfaceCfg(diffuse_color=(0.0, 1.0, 0.0)), ), "cylinder": sim_utils.CylinderCfg( radius=0.5, height=1.0, visual_material=sim_utils.PreviewSurfaceCfg(diffuse_color=(0.0, 0.0, 1.0)), ), "cone": sim_utils.ConeCfg( radius=0.5, height=1.0, visual_material=sim_utils.PreviewSurfaceCfg(diffuse_color=(1.0, 1.0, 0.0)), ), "mesh": sim_utils.UsdFileCfg( usd_path=f"{ISAAC_NUCLEUS_DIR}/Props/Blocks/DexCube/dex_cube_instanceable.usd", scale=(10.0, 10.0, 10.0), ), "mesh_recolored": sim_utils.UsdFileCfg( usd_path=f"{ISAAC_NUCLEUS_DIR}/Props/Blocks/DexCube/dex_cube_instanceable.usd", scale=(10.0, 10.0, 10.0), visual_material=sim_utils.PreviewSurfaceCfg(diffuse_color=(1.0, 0.25, 0.0)), ), "robot_mesh": sim_utils.UsdFileCfg( usd_path=f"{ISAACLAB_NUCLEUS_DIR}/Robots/ANYbotics/ANYmal-C/anymal_c.usd", scale=(2.0, 2.0, 2.0), visual_material=sim_utils.GlassMdlCfg(glass_color=(0.0, 0.1, 0.0)), ), }, ) return VisualizationMarkers(marker_cfg) def main(): """Main function.""" # Load kit helper sim_cfg = sim_utils.SimulationCfg(dt=0.01, device=args_cli.device) sim = SimulationContext(sim_cfg) # Set main camera sim.set_camera_view([0.0, 18.0, 12.0], [0.0, 3.0, 0.0]) # Spawn things into stage # Lights cfg = sim_utils.DomeLightCfg(intensity=3000.0, color=(0.75, 0.75, 0.75)) cfg.func("/World/Light", cfg) # create markers my_visualizer = define_markers() # define a grid of positions where the markers should be placed num_markers_per_type = 5 grid_spacing = 2.0 # Calculate the half-width and half-height half_width = (num_markers_per_type - 1) / 2.0 half_height = (my_visualizer.num_prototypes - 1) / 2.0 # Create the x and y ranges centered around the origin x_range = torch.arange(-half_width * grid_spacing, (half_width + 1) * grid_spacing, grid_spacing) y_range = torch.arange(-half_height * grid_spacing, (half_height + 1) * grid_spacing, grid_spacing) # Create the grid x_grid, y_grid = torch.meshgrid(x_range, y_range, indexing="ij") x_grid = x_grid.reshape(-1) y_grid = y_grid.reshape(-1) z_grid = torch.zeros_like(x_grid) # marker locations marker_locations = torch.stack([x_grid, y_grid, z_grid], dim=1) marker_indices = torch.arange(my_visualizer.num_prototypes).repeat(num_markers_per_type) # Play the simulator sim.reset() # Now we are ready! print("[INFO]: Setup complete...") # Yaw angle yaw = torch.zeros_like(marker_locations[:, 0]) # Simulate physics while simulation_app.is_running(): # rotate the markers around the z-axis for visualization marker_orientations = quat_from_angle_axis(yaw, torch.tensor([0.0, 0.0, 1.0])) # visualize my_visualizer.visualize(marker_locations, marker_orientations, marker_indices=marker_indices) # roll corresponding indices to show how marker prototype can be changed if yaw[0].item() % (0.5 * torch.pi) < 0.01: marker_indices = torch.roll(marker_indices, 1) # perform step sim.step() # increment yaw yaw += 0.01 if __name__ == "__main__": # run the main function main() # close sim app simulation_app.close() ``` ## Configuring the markers The `~markers.VisualizationMarkersCfg` class provides a simple interface to configure different types of markers. It takes in the following parameters: * `markers.VisualizationMarkersCfg.prim_path`: The corresponding prim path for the marker class. * `markers.VisualizationMarkersCfg.markers`: A dictionary specifying the different marker prototypes handled by the class. The key is the name of the marker prototype and the value is its spawn configuration. > **Note** > > In case the marker prototype specifies a configuration with physics properties, these are removed. > This is because the markers are not meant to be simulated. Here we show all the different types of markers that can be configured. These range from simple shapes like cones and spheres to more complex geometries like a frame or arrows. The marker prototypes can also be configured from USD files. ```python marker_cfg = VisualizationMarkersCfg( prim_path="/Visuals/myMarkers", markers={ "frame": sim_utils.UsdFileCfg( usd_path=f"{ISAAC_NUCLEUS_DIR}/Props/UIElements/frame_prim.usd", scale=(0.5, 0.5, 0.5), ), "arrow_x": sim_utils.UsdFileCfg( usd_path=f"{ISAAC_NUCLEUS_DIR}/Props/UIElements/arrow_x.usd", scale=(1.0, 0.5, 0.5), visual_material=sim_utils.PreviewSurfaceCfg(diffuse_color=(0.0, 1.0, 1.0)), ), "cube": sim_utils.CuboidCfg( size=(1.0, 1.0, 1.0), visual_material=sim_utils.PreviewSurfaceCfg(diffuse_color=(1.0, 0.0, 0.0)), ), "sphere": sim_utils.SphereCfg( radius=0.5, visual_material=sim_utils.PreviewSurfaceCfg(diffuse_color=(0.0, 1.0, 0.0)), ), "cylinder": sim_utils.CylinderCfg( radius=0.5, height=1.0, visual_material=sim_utils.PreviewSurfaceCfg(diffuse_color=(0.0, 0.0, 1.0)), ), "cone": sim_utils.ConeCfg( radius=0.5, height=1.0, visual_material=sim_utils.PreviewSurfaceCfg(diffuse_color=(1.0, 1.0, 0.0)), ), "mesh": sim_utils.UsdFileCfg( usd_path=f"{ISAAC_NUCLEUS_DIR}/Props/Blocks/DexCube/dex_cube_instanceable.usd", scale=(10.0, 10.0, 10.0), ), "mesh_recolored": sim_utils.UsdFileCfg( usd_path=f"{ISAAC_NUCLEUS_DIR}/Props/Blocks/DexCube/dex_cube_instanceable.usd", scale=(10.0, 10.0, 10.0), visual_material=sim_utils.PreviewSurfaceCfg(diffuse_color=(1.0, 0.25, 0.0)), ), "robot_mesh": sim_utils.UsdFileCfg( usd_path=f"{ISAACLAB_NUCLEUS_DIR}/Robots/ANYbotics/ANYmal-C/anymal_c.usd", scale=(2.0, 2.0, 2.0), visual_material=sim_utils.GlassMdlCfg(glass_color=(0.0, 0.1, 0.0)), ), }, ) ``` ## Drawing the markers To draw the markers, we call the `~markers.VisualizationMarkers.visualize` method. This method takes in as arguments the pose of the markers and the corresponding marker prototypes to draw. ```python while simulation_app.is_running(): # rotate the markers around the z-axis for visualization marker_orientations = quat_from_angle_axis(yaw, torch.tensor([0.0, 0.0, 1.0])) # visualize my_visualizer.visualize(marker_locations, marker_orientations, marker_indices=marker_indices) # roll corresponding indices to show how marker prototype can be changed if yaw[0].item() % (0.5 * torch.pi) < 0.01: ``` ## Executing the Script To run the accompanying script, execute the following command: ```bash ./isaaclab.sh -p scripts/demos/markers.py ``` The simulation should start, and you can observe the different types of markers arranged in a grid pattern. The markers will rotating around their respective axes. Additionally every few rotations, they will roll forward on the grid. To stop the simulation, close the window, or use `Ctrl+C` in the terminal.