Boolean Operations

If you enter rotation angles, the baffle vane is first rotated about the x-axis, then about the y-axis, and finally about the z-axis.

The Baffle Vane dialog box is a modeless dialog box, so you can leave it open while you do other things like inserting other solid objects, moving objects, changing the view, or applying properties.

Boolean Operations

A common way to manipulate solid objects in a solid modeling program is to use Boolean operations. Boolean operations let you create complicated shapes from simple shapes. Boolean operations can also change the properties of an object. Therefore, they require care and planning in their use.

All three of the Boolean operators (Intersect, Subtract and Union) used in TracePro take two selections or operands, like arithmetic operators. The first selection represents the material and the second represents the tool. For example, to “drill” a hole in a block, you could position a cylinder inside a block, select the block and then the cylinder and then select Edit|Boolean|Subtract. The block would have a hole where the cylinder was subtracted from the block. In TracePro you can perform several operations on one object by selecting a first object for the material and several additional objects as tools, using a Shift (or Ctrl) Select selection. When selecting the tools, hold down the Shift (or Ctrl) key when pressing the left mouse button.

FIGURE 2.23 - Boolean Operations: Two Spheres, Intersection of Two

Spheres, Subtraction of Two Spheres, and Union of Two Spheres

Perform Boolean operations before you assign property values (Material Properties, Surface Properties, and Source Properties).

Note: when you perform a Boolean operation, the choice of existing properties to apply to the resulting object is often ambiguous. TracePro may delete some properties during a Boolean operation.

TracePro 5.0 User’s Manual

2.25

Creating a Solid Model

Intersect

The Intersect operator takes two or more objects and produces the overlapping volume of the solid objects. If the objects do not overlap, the result of the intersection is to delete the objects.

For example, you can create a biconvex lens element by creating two spheres that overlap a small amount, then use the Intersect operator to create the intersection of the two spheres. Since the space that is inside both spheres is in the shape of a biconvex lens, the result of the Intersect operation is to produce a lens.

To use the Intersect operator select two or more objects, you must do a multiple selection in TracePro using the Shift or the Ctrl Key. For example, to intersect four objects:

1.Select Edit|Select|Object or click the Select Object toolbar button.

2.Select the first object. You may click on the object in the model window or use the system tree.

3.Press and hold the Shift (or Ctrl) key and select the second, third and fourth objects.

4.Press Edit|Boolean|Intersect or click on the Intersect toolbar button to complete the intersection operation.

5.The resulting object is the overlapping volume of all four objects.

Subtract

The Subtract operator takes two or more objects and subtracts the overlapping volume of each secondary object from the first object. If none of the secondary objects overlaps the first object, nothing happens. If any objects completely enclose the first object, the result of the subtraction is to delete all the objects.

Note: The result of Boolean Subtraction is highly dependant on the order in which the objects are selected.

For example, if you wish to subtract objects B, C, D, and E from object A, you can do this by first selecting objects A, B, C, D and E in a multiple selection, then select the Subtract operator to complete the operation. The result is

result = A - B - C - D - E

You can create a mirror with a hole in the center by first creating a mirror, then a cylinder that protrudes through the center of the mirror. Then use the subtract operator to subtract the cylinder from the mirror and thereby create the hole. An analogy with a machining operation helps: think of the first object as a part and the second object as a tool. The subtraction operation is like the tool cutting the part.

To use the Subtract operator select two or more objects, you must do a multiple selection in TracePro using the Shift or the Ctrl Key. For example, to subtract three subsequent objects from a “base” object:

1.Select Edit|Select|Object or click the Select Object toolbar button.

2.Select the first object. You may click on the object in the model window or use the system tree.

3.Press and hold the Shift (or Ctrl) key and select the second, third and fourth objects.

2.26	TracePro 5.0 User’s Manual