Week #21 – Creating and Customizing Library Parts
21-8. Rotating and Tilting Objects

ArchiCAD Training (Best Practices Lesson 21-8)

This 52 minute ArchiCAD training will teach you how to create objects that are rotated or tilted from their original orientations. This is particularly useful for forms and shapes that are easier to model on plan as if they were lying on the ground; they can then be flipped up to vertical or any chosen angle when they are saved as an object.

The lesson opens with a demonstration of creating a complex profile for a moulded casing around a door. ArchiCAD has many options for door leafs, some of which are fairly ornate, however it has no built-in options for ornamental casings to complement the door panel.

The complex profile is used with a column to create the casing on the sides, and with the beam tool for the casing across the top. A variation of the profile is generated for the beam element that faces a different orientation, then the beam profile works properly to represent the casing.

An issue is shown with regards to cleaning up the vertical and horizontal elements as they meet: they do not miter or join properly. This can be worked around in some cases, but will be visible in others, so this use of beams and columns is somewhat limited.

Creating Elements Lying Flat on the Plan, then Tilting Up While Creating a Custom Object

The casing outline is drawn lying on the floor plan with the wall tool set to the same profile shape. The wall tool automatically miters and cleans up the corners, so the geometry is clean.

To flip up these elements into position, they are selected on plan and viewed by themselves in 3D. The view orientation is set to a side elevation (parallel rather than perspective view) using the View menu > 3D View Options > 3D Projection Settings dialog. This view from “top” of the plan (90 degrees) will become the top view of the new object when it is saved.

The elements are selected in the 3D view, then the File menu > Libraries and Objects > Save Selection As… Object command is chosen. (In earlier versions of ArchiCAD, this command may be slightly different, but the concept is the same.) The new library part is given a name, then after the process is complete, the object tool is set up to place the new element.

This new object appears “upright” on the plan, and can then be moved into proper relationship with the doorway. If a different size is needed, the object can be stretched (like any other object) but will deform (distort) as it is extended in one direction. To have a clean, proper profile, multiple versions of the object can be created by modifying the original elements and saving the new version of the object. (It is often a good idea to make copies of the elements before changing them, so you have a reference archive of the original shapes to work with in case you need to update them.)

The lesson continues with an even more ornamental application, modeling a wrought iron gate. A photo is dragged and dropped into the plan, then resized to approximate scale. The wall tool is set to appropriate dimensions and material, then the gate is modeled lying horizontally on the ground. The process of viewing these elements in 3D from the side elevation is repeated, in order to create a new library part with the gate set upright.

Adding a Parametric Tilt Angle for a Custom Object

Sometimes it is important to be able to model a group of elements then tilt them at an arbitrary angle, perhaps changing the angle each time the elements are placed. To do this, a basic object is created by modeling a set of 4 profiled walls creating a molded frame casing, selecting the elements on the plan, then using the File menu > Libraries and Objects > Save Selection As… Object command.

This new object is then placed onto the plan, then selected. The library part file is opened with the File menu > Libraries and Objects > Open Library Part command.

A new parameter “rotation_angle” is added for rotation angle, and specified as an angle type of parameter rather than the default length type. In the 3D script, a single line of text is added just after the first few lines of descriptive comments:

  • rotx rotation_angle

This allows the object to rotate around the X-axis by changing the parameter value. However, the 2D symbol does not change when the object is tilted, which could be confusing. To remedy this, the 2D script for the object is edited, adding in two lines after the descriptive comments:

  • project2 3, 270, 1
  • end

This then tells the object to draw the 2D symbol from an accurate “projection” of the 3D model (which will vary depending on the tilt angle specified by the rotation_angle parameter). After the object is resaved, the changes will be visible for the element on the plan, which now has a symbol corresponding properly to the 3D geometry.

BONUS TRICK for ArchiCAD 16+ Users: Converting Elements into Morphs

A final “trick” is shown that will be of interest to users of ArchiCAD 16 and later. The gate elements are selected and converted to Morphs using the Design menu > Convert to Morph(s) command. These morphs may then be rotated freely in the 3D window along any axis or plane, unlike most other ArchiCAD elements.

To specify the right rotation plane, the cursor is placed along one of the edges before clicking to start the rotation. The compass preview will give feedback to let you know that you are setting the editing plane perpendicular to that edge. After setting the origin point and editing plane for this rotation, one can click along the horizontal axis then click on the vertical axis (snapping to the guide lines that show up onscreen) to quickly and precisely rotate the elements 90 degrees (or any other tilt angle).

The morph elements remain intact and can be edited directly (this is not demonstrated in this lesson). For simplicity in managing multiple morphs, it is often a good idea to combine them into a single Morph element using the Design menu > Modify Morph > Union command.

Thank you for visiting the Best Practices Course website. The video lessons are available for members only. If you are an active member and would like to watch the ArchiCAD training video on this page, please login to the website. If you are not currently a member, please visit the following pages for more information and to sign up for the Best Practices Course, the QuickStart Course or for the Best Practices ArchiCAD Coaching Program. Eric Bobrow, Creator of the Best Practices Course
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Eric

ArchiCAD Training: Custom Doors and Windows

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  1. Tom Markunas
    5 years ago

    Nice set of workarounds for what AC is lacking.

    As to the gate, one easy initial step would be to use Photoshop or Elements to Skew the gate’s perspective to be perfectly orthogonal. This would give you an easy trace background for all the parts of the gate.