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ArchiCAD Tip: Priority-based Intersections - Wall and Beams

This functionality enhances Floor Plan intersection of Composite Walls.

Within ArchiCAD, it is possible to assign a intersection priority to:
(i) a complete Wall (via Wall Settings)
(ii) individual wall skins (through Attributes > Composites)
(iii) wall components, if the wall is developed from a Complex Profile (through Design > Complex Profiles > Profile Manager)

An 'intersection priority' (for walls) is simply a number value between 0 and 16.
The higher the value, the more dominant or important the skin is considered.

Wall skins intersect with each other based on their intersection priority, if assigned, or based on the intersection priority of the complete Wall.

These 'intersection priority' values are assigned to composite skins in the Composites dialog, found in Options > Element Attributes > Composites.

Below are two screenshots:
• the first from the standard Wall settings dialog, showing the Intersection Priority parameter when using a single skin wall
• the second showing the composites dialog, with each skin having different priority values, and the location of that paramater for the selected skin

Remember, Composites are a set of 'Attributes', and 'Attributes' are project-specific, not global - thus need to be managed appropriately.

An 'intersection priority' value is assigned to each component/fill of a Complex structure, just as they are assigned to each skin of Composite Structures.

These two types of Walls will also intersect according to the following rules:
• Skins with higher priorities will block/stop skins with lower priorities.
• Skins with equal priorities will form a mitred joint (if they have the same fill pattern)
• Skins with equal priorities will block/stop each other (if they have different fill patterns)

Some basic rules-of-thumb for assigning intersection priority numbers
• Finish skins, such as plasterboard, such be given lower numbers, e.g. 0-4
• Brick finishes and/or voids, such be given intermediate numbers, e.g. 5-8
• Structural skins, such a concrete block, should be given higher numbers, e.g. 9-12

Beam elements also have an intersection priority value, which are also simply a number value between 0 and 16.
Thus, when a Wall intersects with a Beam in 3D, ArchiCAD can determine which is "dominant" depending on their Priority Numbers.
Based on the comparison, either the beam will automatically cut a hole in the wall, or the wall will remove a slice from the beam.

Describing the screenshot below:
• the beam in the foreground is Priority 9
• the beam in the background is Priority 7
• the wall is Priority 8
As can be seen in the foreground, the beam is piercing a hole in the wall, hence the additional contour around the intersection area.

An example of similar wall structures with different priorities and different intersection outcomes is linked below.
This diagram was created by ArchiCAD-Talk User, Cecilia (and linked here directly from ArchiCAD-Talk)
It was originally referenced in the ArchiCAD-Talk Forum discussion here

Another useful link relating to Composites is given here, created by James Murray.

Last Updated: 06 February 2013