GroIMP allows the reuse of external 3D models (e.g., ``.dtd`` files created in the RGG editor) by referencing them directly in XL code. This is done using the ``Reference(…)`` constructor.
To instantiate a 3D object into the scene:
Reference("cherry_new.dtd");
This creates a single node representing the geometry of the external object but does not import its internal graph structure.
This example creates three identical tree models placed along the y-axis:
protected void init()
[
Axiom ==> for(int i=0; i<3; i++)(
Translate(0, 1, 0)
[
Reference("cherry_new.dtd");
]
);
]