For cable tray: In the Add Cable Trays dialog box, under Layout Method, click Use Rise/Run, and specify a value in degrees. Then click Cable TrayFind or Conduit. You can perform the following to route cable trays in the 3D model. Before routing, consider the following guidelines: Cable tray lines are continuous, consisting of interconnected straight cable tray pieces and. When I change the size of a block (for example cable tray, length of pipe) I click on the object, then click one of the arrows to amend it. Create a new project. Learn how to draw pipe and duct networks, connect components, generate schemes, and create slots and openings.