# INTRODUCTION

ProBasic / ProSurf

Tutorial on Entities

Copyright 1997 by New Wave Systems, Inc.

New Wave Systems, Inc.

79 Narragansett Ave.

Jamestown, Rhode Island 02835

USA

Tel: (401) 423-1852

Fax: (401) 423-1810

Web Site: newavesys.com

Tutorial on Entities for ProBasic/ProSurf

The best way to develop a good understanding of any Computer-Aided Design (CAD) program is by studying the geometric entities provided by the program and by studying the commands required to create a new entity, modify an existing entity, and to delete an entity. Entities are basic geometric objects used to construct more complicated 2-dimensional (2D) and 3-dimensional (3D) objects. Entities are also the lowest level of geometry that can be created and manipulated by the program. This tutorial introduces you to the entities and the basic entity operations provided by the ProBasic and ProSurf programs. (Note that when the tutorial refers to ProSurf in this tutorial, it really refers to BOTH ProBasic and ProSurf.)

ProBasic and ProSurf provide the following basic geometric entities:

1. Points

2. Lines

3. Poly-lines

4. NURB Curves

5. Combo line/curves

6. NURB Surfaces

As you will see, ProBasic and ProSurf combine entities 2 - 5 (lines, poly-lines, curves, combo curves) into one multi-purpose entity (generally called a 'curve'). This may seem more complicated than necessary, but it does simplify many tasks and makes it very easy to define complicated wire-frame objects. You may find these 'curve' entities much easier to use than your general-purpose CAD program (referred to as GP-CAD in this tutorial)

Aside: You will notice that there can be a good size overlap in functionality between ProSurf and your GP-CAD program (like AutoCAD LT). Although ProSurf specializes in surface shaping and smoothing, it can also do some tasks usually done in your GP-CAD program. After some experience with the ProSurf program, you may find there are many more non-boat-related tasks that can be performed in ProSurf and then sent over to your GP-CAD program using a 'DXF' or 'IGES' geometry transfer protocol.

In the following sections of this tutorial, keep in mind these questions:

1. What are the basic geometric entities?

2. How can the entities be used?

3. How do I create a new entity?

4. How do I manipulate an existing entity?

5. How do I delete an entity?

This tutorial assumes that you know how to start up the ProBasic/ProSurf program and you know how to perform the basic operations of any Windows-type program. If you haven't done so already, please go through the Overview tutorial before starting this tutorial.