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Add Properties to Classes vs. Groups

In Simplebim you can add properties to:

  • Object classes
  • Object groups

Object class in the most common case and this adds the property to all objects of a given object class (like wall).  When you add properties to object groups you add the properties to the group itself, not to the objects in the group. Let’s say you have a group representing a task, which has a start and end date. You can add the start and end date properties to this group itself and view/edit those properties by double clicking on the group in the Objects palette. In contrast, when you select the group in the Objects palette the Properties palette shows the properties of the objects in that group.

The fact that all objects of the same object class have the same properties is common for applications because this is how object oriented programming works by default. However, IFC does support attaching different properties to objects of the same object class. When such an IFC model is imported into an application the typical outcome still is that all objects of an object class have all the properties that exist on any of the objects of that object class. This happens because of how applications work, not because of IFC.

When importing IFC Simplebim works like most applications and all objects of an object class have all the properties that any of the objects in the object class have. However, when exporting IFC Simplebim only exports properties that have values. This means that if a property is irrelevant for a specific object, you can leave its value empty and this property will not be exported to IFC for the object in question. In the Simplebim user interface you can also set a filter in the Properties palette that hides all empty properties. As a result you can use Simplebim just as if all objects had only the properties they really need, even though in reality they have all the properties.

As a summary:

  1. Add all properties to the object classes
  2. Set the property values only for the objects for which the properties are relevant
  3. Hide the empty properties in the Simplebim Properties palette. This means that you will see in Simplebim exactly what you want.
  4. When you export to IFC, Simplebim will only export properties that have values. This means that the IFC will be exactly like you want.
  5. However, when you import the exported IFC into another application the empty properties will probably appear back. This is not because of Simplebim or IFC, but because of how that application works.