|Show Diagram – display the selected diagram in the scene view
Load Diagram – Select and load an image to be displayed in the scene view.
Clear – Clear the diagram.
Diagram Scale – Set the scale in meters of the diagram
Draw Scale – Define the diagram scale. Click this button and then click on the start and end of the diagram scale (assuming it has one) to define the size of the scale. Then edit the scale value above to ensure your diagram is rendered at 1:1.