Its possible to define and utilize offset frames with a T-probe or T-mac. This allows you to take a 6D measurement, but record a frame that is spatially offset from its base position as the measurement. The offset frame utilizes a fixed transform relative to its position and orientation. Defining one is idea for scenarios where you are defining a tool tip on a robot for example.
An offset frame can be defined and saved within a measurement profile. Additional details on this can be found in the section on measurement profiles.
An offset frame can also be defined as part of a target definition. This is important for multi-sided T-Mac’s because it allows measurements from each face to return a common transform. It also provides an option to have the offset applied to all measurements from this target.
Rigidly mount the T-Mac as desired such that it is visible from your instruments location. Then record or construct the desired frame you wish to return from the measurement. This may means measuring the end effector for the robot for ex- ample. Ensure that the T-Mac and Robot do not move. Also measure common points in case additional instrument stations will be required and a tie in will be necessary.
Lock onto the T-Mac and set the measurement profile to a 6D Discrete Measurement profile (this will allow you to measure an offset transform for the target definition).
Open the Reflectors and Targets database and click on the manufacturer’s definition to open the offset frame definitions.
This dialog allows you to select from a list of offset frames (only a single offset frame will be visible when locked onto a regular T-Mac or T-Probe). Select the desired frame which corresponds to the desired face and a familiar offset frame measurement dialog will open. You can then select the offset frame and measure the current position to compute the offset definition.
Move the tracker without moving the robot to a new location and tie it in to the prior station. You can then add an additional offset frame for this T-Mac face. The process can be continued until each face of the T-Mac has been calibrated with offset frame definitions.
These offset frames will be persisted for each face of each reflector. You may clear a given offset frame by clicking its row in the grid and selecting (Clear Frame).