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Starting Your Model

Modeling practices using MGED can be quite individual. The following is a suggested modeling method to start with; you may end up developing your own style as you become more familiar with MGED.

First of all, decide how you want to represent your model, including the amount of detail, types of solids and regions necessary. Have an accurate sketch or engineering drawing available, so that you can easily tranfer its information into the types of primitive solids necessary to create your model. Where possible it is recommended to start with a large block solid and ``subtract'' pieces from it. In this way you avoid errors with abutting faces of a collection of solids ``unioned'' together.

Next the solids are created using the make, cp, mirror or in commands. Depending on the complexity of the model, the solids may be created in the desired location or created at the origin and later translated to the desired location. Creation at the origin provides an opportunity to take advantage of possible symmetries in the geometry. Once all the solids are finished it is time to create the region[s], which will describe (to MGED) how to combine the solids to represent the model.

The region[s] are then given the desired item/air code (if this is necessary, otherwise leave it as the system default value), and material codes. The regions are then put onto a group, usually for functionality only. A group has no operations as such (like union [u], intersection [+] or difference [-]) and is just a collection of objects for convenient naming of a whole screen or collection of objects.



Wed Feb 16 13:46:53 EST 1994