3D Monitoring is a subsection of the Monitor toolbox that provides tools that will display information in 3D view in real-time. 

You can find descriptions of these checkboxes with the help button at the top right in the Monitor toolbox.

Real time hidden lines - Real-time hidden line makes hard to see lines in the 3D more visible.

Show Wireframe - Displays the whole wireframe of the 3D model in real time.

Show RED frame rate - Displays the current frame rate of CET as well as the time taken by the application as well as the red engine. It will also pops up a dialog that displays 3D stats as well as LOD budgets and its associated graphs.

Colorful LODs - Gives a color to the 3D to show which LOD they are currently using. (Color Legends : Yellow : Super Blue  : High Green  : Medium Red  : Low)

Trace Render Time - Displays the Render time on your emacs console once the render is completed.

Show BSP - Displays the BSP bounds in the 3D.

Identify CmSym Snappers -For catalogue items, those that are using cm3D will have cm3D tag and those that are using cmSym will have a cmSym Tag. Makes it easier to identify which format are the catalogue using.

Enable LOD Budget Update - Enable/ Disable Dynamic LOD Update. Only for CET version 9.0 and above. The old LOD updater uses pixel size to determine which LOD it needs. The new one has a budget that it will use to determine which LOD supposed to be high and low.

Enable Dimension Monitoring -Enabling this and clicking on a desired snapper will show its dimensions, variable name, XYZ axis and center point all in real time 3D.