Smart 3D Modeling Blog Series: Interactive Door-Wall Assembly – Blog 2 of 2

You can access the first blog from this blog series here.

Sample files for this blog series are shared here

Before you create a door-wall assembly, you need to create a parametric door cell and create desired variations of it. Following steps demonstrate the same:

  1. In a 3D model, create a Rectangular profile on the XY plane. Set the ACS origin at the bottom left corner.
  2. Apply 2D Fixed constraint to the bottom left vertex and direction of the segment.
  3. Apply 2D Parallel constraint and Perpendicular constraint to the edges of the profile. These constraints fix the rectangular shape of the profile so that any changes in the dimensions will not change the geometry. (If Place Block tool is used to create rectangular profile these constraints are taken care of automatically).


  4. Apply 2D Distance constraint to the two edges of the profile indicating the door width and the door thickness. This allows you to create variations of the door with respect to its width and thickness. Refer the image below.
  5. Create three variations for door types with different variables for dimensions (height, width and thickness). Variables are named values defined within a model, which can be used to drive a model’s geometry parametrically; a Variation is a named set of values associated with a variable. Following are the steps to create variables and variations:
    1. Open the Variables dialog by clicking the “fx” icon in the Dimensional ribbon group of the Constraints tab.
    2. Select the Variables section in the Variables dialog and click New.


    3. Give a desired name (e.g. D_Width) and set its type, value and other options in the Properties section. Similarly, create variables for other dimensions.
    4. Once you create the variables, select the Variations section and click New to create a variation. Add values to the dimensional variables. (You can also assign Variables directly associated with Item Types for doors.)
    5. Similarly, create more variations with different values for the door dimensions.
  6. Link variables for door width and door thickness to distance constraints applied to the profile. The profile is modified to display the assigned variables.


  7. Extrude the rectangular profile with extrude distance linked to door height variable using the Solid by Extrusion tool.


  8. For all the different variables and variations created for door types check if the door type changes as per the selected variation. From the Variables dialog select and apply the desired variation.


We will now create a simple assembly of a wall and a parametric door cell and set constraints to make it interactive.

  1. In a new DGN file, create a simple wall profile in a 3D model, with an opening for placing the door cell.
  2. Assign 2D geometric constraints like Fixed constraint to one of the vertices, Coincident and Perpendicular constraints to the edges as demonstrated in the video. (These constraints fix the shape of the wall in such a way that future changes to its dimensions will not disturb the geometry).


  3. Open the Cell Library dialog from the Cells dialog launcher in the Annotate tab and attach the door cell.
  4. Double-click on the cell to start the Place Parametric Cell tool.
  5. Select the desired Variation in the Place Parametric Cell tool setting and place it in the wall opening.
  6. Apply 2D Coincident constraint to the corresponding edges of the door and wall. (Constraints enable the wall opening to adjust to the variations in the door sizes.) 



  7. The opening in the wall adjusts to fit to the door dimensions. You can now extrude the wall profile to give desired wall thickness.
  8. Select the door using the Element Selection tool and from the Properties dialog change the Door Cell variations. The opening in the wall changes to adjust to the changing door sizes.

Changes in the parametric cell are reflected in the associated element and this makes the assembly interactive. Similar assemblies can be created for windows and other openings in walls as well as any other similar design situation.