To do this, LEGION Model Builder must be open.

1. Within LEGION Model Builder, select File > Import CAD.
   • The Open dialog box is displayed.
2. Browse to the CAD file to import, select it and click Open.
   • If there are any types of CAD object that LEGION Model Builder doesn’t recognise, the Incompatible CAD Detected window is displayed. This lists all incompatible CAD elements by type and number.
3. Check the contents of the window and click OK to move on.
   • The Layer Selection dialog box is displayed.
     
   • This lists all the Layers available for import and enables selection of Layers for inclusion as part of the import and also for inclusion in the eventual simulation. The Layers are also colour-coded:
     • White Layers contain fully supported CAD
     • Amber Layers contain some unsupported CAD
     • Grey Layers contain no supported CAD
     • Blue Layers are empty and contain no CAD at all
4. For each Layer to be imported, ensure that the Import tick box is ticked. To exclude a Layer, untick the box.
   Tip: If a Layer is hidden (a No in the Visible column) the Import option is automatically unticked.
5. For each Layer to be imported as Simulation CAD, ensure that the Simulation tick box is ticked. To exclude a Layer, untick the box.
   Tip: A Layer ticked as Simulation will be included in the eventual simulation that runs in LEGION Simulator. Take care to tick only those CAD Layers that contain genuine obstacles to Entity movement.
6. For each Layer that contains small objects which Autonavigation should ignore, ensure that the Autonavigation box is unchecked (this saves on memory and permits more accurate pedestrian movement).
7. By default, each Layer has all import options ticked if the Layer is not empty and all CAD therein is compatible. The Restore previous settings button can be used to set Layer states to the values they had after the last successful import. See the subsequent section Restoring Previous CAD Import Settings at end of this section.
8. Click OK to continue with the import.
   • Settings for Import, Simulation and Autonavigation tick-boxes for each named Layer are saved and can be restored in a future CAD import.
9. To import all CAD lines as the opposite of the current background colour, check the box marked Import all CAD in black or Import all CAD in white.
   • The box label changes to suit the current background colour.
10. Click OK. The CAD Import progress bar is displayed. If an imported CAD Layer name matches a CAD Layer already in the model, a prompt asks how to deal with this:
    
    • Automatically rename the CAD Layer = the Layer being imported is given a new name that does not exist in the model.
    • Use the existing CAD Layer (already present in model) = the Layer is not imported from the CAD file, and the existing Layer remains in the model.
    • Overwrite existing CAD Layer (use newly imported) = the contents of the existing Layer are deleted, then CAD elements from the CAD file are added to it. This effectively replaces the existing Layer.
      • If overwriting a CAD Layer bound to Platform-Train Interface Platform objects (see Platform-Train Interface (PTI) topic), those Platforms are automatically unbound. An alert is shown after import:
        
      • Affected Platforms are listed in the Output Bar. Clicking on a message will select the Platform object in the CAD workspace:
        
      • When progress is complete, the Drawing Units/Scale dialog opens.
11. Ensure the Drawing units and Drawing scale settings are correct for the CAD plan being imported.
12. Check the box marked Adjust model dimensions to fit imported geometry (this ensures that the LEGION model is large enough to contain the obstacles on your imported plan).
13. Click OK.
    • The CAD file appears in LEGION Model Builder workspace and the Object Directory and Layers dialog are populated with the new CAD Layers and objects.

After importing CAD, make sure that the correct CAD Layer is active. See Making Layers active.

Restoring Previous CAD Import Settings

By default, each Layer has all import options ticked if the Layer is not empty and all CAD therein is compatible. This happens each time you import CAD into a model, which can be inconvenient if CAD is frequently re-imported and different Layers require different import options.

For example, at the first CAD import the import options are configured like this:

When the OK button is clicked in the Layer Selection dialog, the import options of each named Layer are stored so they can be used again (i.e., restored) later.

Subsequent imports will set Layer import states to their default values (because LEGION Model Builder does not whether it should repeat the previous settings or start again):

Import, Simulation and Autonavigation tick-boxes can be restored to their previous settings by clicking the Restore previous settings button.

Import options are stored for each named Layer, so if the Layer still exists in the current CAD file its options will be restored to their previous import states.

Note: If the CAD file contains Layers that were not present at the previous import, there are no cached import options for them. Such Layers are assigned default states based on visibility, content, and compatibility.