StarLogo Project:

3D

WHAT IS IT?

This project shows how to create and rotate simple three-dimensional objects in StarLogo.

Objects are created by placing turtles randomly on the surface of the object.

HOW TO USE IT

The SPHERE, CYLINDER, and CUBE buttons create those objects.

The TURN-X, TURN-Y, and TURN-Z buttons make the objects rotate around the indicated axes.

THINGS TO NOTICE

Depth (along the Z axis) is indicated by shade of red.

Some objects (such as the cube) are easy to "see" from certain perspectives, but seem like a mess of turtles from other perspectives.

EXPLORATIONS

* Create other three-dimensional objects.

* Experiment with other ways of indicating depth along the Z axis (other than shade of color).

* To display the turtles on the two-dimensional screen, the turtles are projected directly onto the XY plane (as if viewed from inifinity). Change the program so that the user can control the position of the "camera" (so that points with the same X and Y values do not necessarily project to the same place on the XY plane).

* It is not always obvious how to distribute turtles evenly on the surface of a three-dimensional object. Try other ways of creating spheres and cylinders.

STARLOGO FEATURES

The TURN procedures use actual values rather than the trig functions, since the trig lookup tables in StarLogo do not have as many digits of accuracy.