1. V106.02 part 2 Obtained from a Guildford County workshop- Summer, 2014

2.  All 3D modeling programs contain certain basic geometric shapes that can be combined with or subtracted from other shapes to form more complex objects.  Some programs contain more objects than others, but a sample list of basic primitives includes: Sphere Cube or box Cylinder Torus Cone Plane

3.  Arcs, ellipses, circles, curves, and freehand curves are basic 2D shapes typically provided within modeling programs called SPLINES. Shapes may be combined to create complex objects.

4.  Splines are curves or polygons that are composed of segments that can be manipulated by control points placed along the curve.  Control points may be made “active” and then dragged using a handle attached to the point.

5.  Typical parameters include center point, radius, height, width, etc.  Parameters affect the size, placement, and orientation of the object.

6.  Values provided automatically by the software are called the defaults.

7.  Boolean tools or operations are used to create objects by combining, subtracting, or determining the common intersections of various objects such as primitives.  Union or Addition (+ or  ) is used to combine objects together into one new object.  Subtract or Difference (  ) is used to remove part or all of an object where objects overlay each other.  Intersection (* or  ) is used to calculate the overlapping volumes of objects so that the overlap becomes the object.  Named for the British mathematician George Boole.

8.  Extrusion, sweeping, or lofting allows you to create a 2D shape and then extend it along a path or curve to form a 3D object. The 2D shape may be open (curves that do not connect back onto the beginning or closed (lines connect back onto the beginning).

9.  A variation of sweeping is lofting, where a series of curves (open or closed) is lofted or spaced parallel to each other, and then a surface is generated that connects the contours.  Lofting may also be done using a profile shape and a curve along which the profile is lofted. An example of where lofting is used would be for modeling boat hulls and terrains.

10.  Revolve or lathe operations allow the user to create a 2D shape and then revolve it around an axis.  Lathe operations emulate the lathe found in manufacturing shops. A lathe is a tool used to rotate and shape material by bringing cutting tools against the material while it spins.  T he revolution may be a full 360 degrees or any smaller angle.  Lathe operations are often used to model objects such as bowls, bottles, and dishes.

11.  Transformations or Transforms are actions that scale, rotate, and move objects  Scale changes the size or proportions of an object along one or more axes.

12.  Rotate refers to tilting or changing the direction that an object is facing.  Rotation is usually assigned to a particular axis. For example, the object might be rotated along its X- axis.  Most programs assign a default location for rotational axes. This location (pivot point) may need to be relocated to create to the desired movement.  Move is used to advance an object from one position to another.

13.  Modifiers are used to modify an existing shape.  Examples include taper, bend, twist, smooth, and stretch.

14.  Copy or Clone tools allow selected objects to be reproduced in their exact size and form.  Mirror tools allow selected shapes to be copied or flipped about a defined center.

15. END PART 2