rtabmap_conversions

Conversions between RTAB-Map library types and ROS 2 messages.

This package is a library only — it contains no nodes, no launch files and no parameters. Every other rtabmap_ros package that touches a message goes through it: rtabmap_slam, rtabmap_odom, rtabmap_sync, rtabmap_util, rtabmap_viz and rtabmap_rviz_plugins.

You only need it directly if you are writing your own node against RTAB-Map’s C++ API and want to publish or subscribe to rtabmap_msgs.

Contents

• Usage
• What it covers
• Conventions worth knowing
• License

Usage

Add the dependency to your package.xml and CMakeLists.txt:

<depend>rtabmap_conversions</depend>

find_package(rtabmap_conversions REQUIRED)
target_link_libraries(my_node rtabmap_conversions::rtabmap_conversions)

Everything lives in a single header and the rtabmap_conversions namespace:

#include <rtabmap_conversions/MsgConversion.h>

// A pose message to an rtabmap::Transform and back.
rtabmap::Transform pose = rtabmap_conversions::transformFromPoseMsg(msg.pose);

geometry_msgs::msg::Pose out;
rtabmap_conversions::transformToPoseMsg(pose, out);

The naming is uniform: xxxFromROS() converts a message into an RTAB-Map type, xxxToROS() goes the other way. ToROS() functions write through a reference parameter so the message can be reused; FromROS() functions return by value.

What it covers

Full signatures and per-function notes are in the API documentation and in MsgConversion.h.

Conventions worth knowing

These cut across the whole API and are not obvious from the signatures. Per-function caveats — object lifetimes, which fields a given ToROS() fills — are documented on the functions themselves.

Null transforms. RTAB-Map distinguishes a null transform (unknown) from identity. Over the wire this is encoded as an all-zero quaternion, so transformFromGeometryMsg() and transformFromPoseMsg() return a null rtabmap::Transform for one. Always check isNull() before using a result. tf2::Transform cannot represent this — it stores rotation as a basis matrix — so transformToTF() returns a bool instead.

CameraInfo matrices are fixed-size arrays. k, r and p are std::array, so they are never “empty” — an unset matrix is all zeros. cameraModelFromROS() treats a zero k[0]/p[0] (the focal length) as absent.

License

BSD-3-Clause. See the repository root.