In the case of Occurrence <-> IFC Occurrence configuration, you will note that there are a "+" buttons available to the right for the configuration name;
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These enable you to create creating "Sub" Configurations which you may want are used to apply to only Occurrences of specific IFC Categories.
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To create a Sub Configuration which you that would like to apply to only IFC Category “Walls”, select the "+" button within the Occurrence <-> IFC Occurrence Configuration, then select "Walls" as follows:
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After selecting "OK", a new (Sub) Configuration window will appear. Here , you need not (and cannot ) set up the "Key Attribute used for comparing" (your Main “Occurrence <-> IFC Occurrence” Configuration would have that already), but rather you can pick is where the properties on either side are added and choose the direction in which you'd like the values of the properties to go.
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The Category specific configurations will allow you to synchronize different data based on what type of object you to synchronize. The result in the Attribute Configuration Settings looks like this, where there are established two category-specific configurations for IfcWall and IfcSlab;
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