To create your own models, see alternatives on the 3D models page Blender, Art of Illusion, Sketchup etc. are all good (but very different) alternatives. In addition, you could look at editing advanced properties for your models. See the DefaultFurnitureCatalog.Properties (and there is a short intro on how p. 9 of the SVG/properties guide).

If you create your own models, note that in addition to [font=courier new]LIGHT_SOURCE[/font] and other properties, you can also add [font=courier new]PLAN_ICON [/font] to use electrical symbols for each item to change their display in the 2D view.

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