im have 3dmodel(obj) how i can create a rule with this model like paris cga and courtyard.cga
You can use the i() operation to insert obj files.
In the Paris example, the code extrudes a footprint to the building's height, then it splits it into facades and floors and puts textures on each floor. In this example, there is no obj file for the entire building.
To create a courtyard, you can use setback() to split a lot into a courtyard and building footprint. Then, insert the obj on the building footprint using i(). To get different shapes for the courtyard, you can also use other operations (or a combination of them) like split, splitArea, offset, setback, shapeL, shapeU, shapO, and innerRectangle.