You may wish to fix the size of a riser pipe or duct section.
Consider this simple CWS project with a riser between floors:
In this example, the riser has sized to 22m, but we wish to fix it at 15mm. To enable us to select the riser correctly, we need to set the pipe height to the mid point between the start and end of the pipe. The lowest point is .45m, and the highest 3, the midpoint is 1.7m.
From the Pipes menu, select the Defaults option. Now choose the "Special Height" from the dialog and set it to our mid point height (1.7m). Close the dialog and select the Fix/unfix pipes option from the Pipes menu.
While in Fix/unfix mode, RIGHT click as near to the center of the riser section as possible. It will help if you zoom into this area before trying to select the riser point.
If you select the area correctly, you will see a coloured dot highlighted in the center of the riser/floor change connector marker as in the zoomed image below. Once the section is correctly selected you can set the parameters of the section, as required.