# Revision history [back]

Hi Venkat,

As you might be aware, a rotation can be expressed in several different representations. RPY is often used as it is fairly easy to visualize and recognize what the rotation is, but it has some problems with regards to singularities. Under the hood, TF uses quaterions, which means that if you are broadcasting and listening to a transform in euler angles like RPY, it will have to translated to and from quaternions. A single rotation can be expressed in several different set of RPY angles, for instance, a Pitch of 180 degrees is identical to first a roll of 180 degrees and then a yaw of 180 degrees (Like your camera_frame -> bundler_camera_frame)

An easy way to check that the transforms are what you intend for them is to use the TF plugin in RVIZ. If they are not what you intended, there is another problem, but I suspect this was the root cause.

Hi Venkat,

As you might be aware, a rotation can be expressed in several different representations. RPY is often used as it is fairly easy to visualize and recognize what the rotation is, but it has some problems with regards to singularities. Under the hood, TF uses quaterions, which means that if you are broadcasting and listening to a transform in euler angles like RPY, it will have to translated to and from quaternions. A single rotation can be expressed in several different set of RPY angles, for instance, a Pitch of 180 degrees is identical to first a roll of 180 degrees and then a yaw of 180 degrees (Like your camera_frame -> bundler_camera_frame)--> bundler_camera_frame)

An easy way to check that the transforms are what you intend for them is to use the TF plugin in RVIZ. If they are not what you intended, there is another problem, but I suspect this was the root cause.

Hi Venkat,

As you might be aware, a rotation can be expressed in several different representations. RPY is often used as it is fairly easy to visualize and recognize what the rotation is, but it has some problems with regards to singularities. Under the hood, TF uses quaterions, which means that if you are broadcasting and listening to a transform in euler angles like RPY, it will have to translated to and from quaternions. A single rotation can be expressed in several different set of RPY angles, for instance, a Pitch of 180 degrees is identical to first a roll of 180 degrees and then a yaw of 180 degrees (Like your camera_frame --> bundler_camera_frame)) For your base_link --> camera_frame, it also works out.

An easy way to check that the transforms are what you intend for them is to use the TF plugin in RVIZ. If they are not what you intended, there is another problem, but I suspect this was the root cause.