Saturday, May 13, 2017

Revit Show Hidden Lines Overview

Ever since Revit 2015, every model view, except perspective, has an instance parameter called Show Hidden Lines. This parameter has up to three possible options available via a drop-down list; None, By Discipline and All. This is a high-level way in which to control how hidden lines function in a given view.

  • This view parameter can also be controlled by a View Template.

By Discipline

Mechanical and Electrical both have specific hidden line options in their respective settings dialog on the Manage tab. These discipline specific settings can be overridden per the other two options, as we will discuss next.

  • Prior to Revit 2015 By Discipline was the only "hardwired" option. 


This setting will turn off all hidden lines controlled by the MEP settings AND those controlled by the Show Hidden Lines tool on the View tab.
  • FYI: The Show Hidden Lines tool has been around for a long time. This tool is used to reveal the outline of an item which is being obscured by another element. This appears to only work when the view’s discipline is set to Architectural or Coordination.
There are a few things None does not affect. This setting does not affect the Beyond line controlled by elements falling between the Bottom and View Depth settings in the View Range dialog. This does not affect the hidden lines set using the Linework tool or line work assigned to the Hidden Lines sub-category within a family. It is interesting, however, that the Show Hidden Lines tool is also dependent on the Hidden Lines sub-category and IS affected by the None setting.

The image below shows a simple reception desk family in plan view, note these three points:
  • Item #1 was set to use Hidden Lines via the Linework tool 
    • Selected line style controls color and pattern
  • Item #2 was set to Hidden Lines via the line’s properties within the family
    • Hidden Line color and pattern controlled by Furniture sub-category
  • Item #3 has Hidden Lines showing using the Show Hidden Lines feature
    • This is a low wall extending under the worksurface
    • Hidden Line color and pattern controlled by Wall sub-category
When Show Hidden Lines is set to None, only the lines related to Item #3 are hidden. Everything else stays the same.


This option is interesting in that all obscured edges appear as Hidden Lines in the entire view. The images below show the same reception desk in plan and 3D view. Notice all the 3D geometry is shown through the work and transaction surfaces. Also note that the color and line style is being controlled by the elements sub-category (in this case, furniture). Also, the view scale controls the line pattern size.

Individual hidden lines can be removed using the Linework tool with the line style set to <Invisible Lines>.

This functionality is not available for perspective views nor does it work on linked models. The “All” option is also not an option for MEP plan views.

The “All” option is available for MEP 3D views. The example below is a bit complex but highlights the topic under discussion well.

Discipline: Mechanical, Show Hidden Lines: All

Below are three images of the same area of an MEP ventilation plan, each with a different Show Hidden Lines setting selected. FYI: Because “all” is not an option for the Mechanical discipline (in plan view), the Coordination discipline was used in the “all” example below.

Discipline: Mechanical, Show Hidden Lines: None

Discipline: Coordination, Show Hidden Lines: All 

Discipline: Mechanical, Show Hidden Lines: By Discipline

Another example of using the “All” option for Show Hidden Lines is documenting wall openings in structural drawings. In the first image below, a plan view, we see an opening in the wall. Prior to Revit 2015, if the opening did not occur directly on the section cut plane the opening was not visible by default. Now, with the section view’s Discipline set to Structural and Show Hidden Lines set to All, the opening’s edges will appear IF the opening is within the view depth—as shown in the second image below. Notice that the Hidden Lines sub-category for Walls is what governs the lines displayed. Architecturally this is not as clean as the window, in the opening, would also appear dashed.

So that's a quick overview of the Show Hidden Line view property in Revit! Please comment on this post if you have any additional related tips or tricks.