Creating proper connections is done automatically and properly in ArchiCAD depending on the intersection priotity set within the Building Material dialog. But In some instances this may not occur as anticipated, especially referring to the latest versions of ArchiCAD, namely version 17 and 18.
A specific instance where unwanted connection may occur is where a Solid Composite Wall and a Cavity Composite Wall of same intersection priorities are in connection. Even though one may expect proper connection to occur automatically, You may find that the Cavity Wall takes precedence at the corner of intersection and by so doing exposes the section of Cavity Wall, and in most cases this may not be practical for Architectural Drawing purposes.
But fortunately to avoid this inconvenience ArchiCAD provides a way to workaround this issue, it involves changing of connecting skin intersection priorities and application of Legacy mode. Below I have outlined a typical example to provide a solution to this issue.
First lets outline the list of materials and their intersection priorities before performing the workaround, see below;
When Composite skins intersection priorities are set as in the table above, we will not achieve proper connection. See below;
To achieve a proper connection, Intersection priority should be lower for the Internal Wall of the Cavity, as a result we may have to create a copy of a Brick skin in the Building Material Dialog Box and assign a lower Intersection Priority
The connection looks better now but if you take a closer look you will see that there is a separator line between the Solid Wall and the Cavity Internal Wall which may provide false interpretation of the connection.
To rid this Separator Line we have to check the Use Legacy and Intersection Surface Methods For Model Elements radio button, Go to Options > Project Preferences > Legacy and Click Ok.
See Video clip below:
If you think Cavity and Solid Composites should auto connect properly without a workaround for future versions of ArchiCAD please drop a comment and we shall log a wish.