Isn't this what the "Scatter Tool" does?

You can scatter 3D or 2D objects over 2D or 3D surfaces with or without surface alignment. It can create entire forests using billboard trees that use only 1 polygon that can render super-fast, and won't slow Poser down.

All of these examples were scattered over the default Poser GROUND plane.

Here's an example of scattering over 2D and 3D surfaces with surface alignment.

Surface alignment can be calculated even over morphed 3D objects.

You can even scatter figures of you like, with or without surface alignment. 

The interface is very simple. Below is the new version for Poser 12 and 13, which added some new features, like scattering over custom areas we can PAINT with the Group Tool. 

More examples of scattering in Poser 12.

Here's how you paint scattering areas with the Group Editor directly on the surface:

Create real-time CROWDS with billboards:

Each person is a single poly, so Poser won't even notice there is a 100 people on the scene. They auto-follow the camera, so they are always facing the right way for renders. 

There is an older version for Poser 11 (Python 2), and a new one for Poser 12 and 13 (Python 3). 

Hope this helps. :)

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