Boolean Operations

Here are a couple of practical examples.
Boolean Operations This tutorial can be completed using Bryce versions 3 to 5. Boolean Operations in Bryce are named after George Boole (1815 - 1864) who invented a system of algebra upon which they are based. Although it has a scary scientific-sounding title there is nothing particularly complicated about it. The operations consist of applying one of three attributes to different Bryce primitives which are then grouped together to cause the Boolean effect to become visible. The three attributes are Positive, Negative and Intersect. They are enabled by clicking on the [A] button and checking the appropriate attribute.
	Here are two objects, a sphere and a cube, centred on each other. The cube has been given a Positive attribute and the sphere a Negative attribute. Both are selected and are about to be grouped by clicking on the [G] button.
In this image and following images the Positive object is Green and the Negative object is Red. On the left are the two objects before grouping and on the right the objects after grouping. As you can see the space occupied by the negative object has been cut out of the positive object.
Here the cube is now negative and the sphere is positive and the images show the result before and after grouping. Whenever you use an object with a Negative attribute you also have the option of checking the Transfer Material of Negative Boolean. With this checked the Red from the negative shows on the cut surfaces of the positive. If it was unchecked the result would be all green.
	If one of the objects is given a Positive attribute and the other an Intersect attribute (it doesn't matter which, the result is the same) then when they are grouped you get the effect shown to the left. Only the space which is common to both objects is rendered. That is all there is to it.
It should be noted that the objects used can be single objects or grouped objects. When using groups it is important to make sure all the component objects have a positive or negative attribute and that the group itself is also given a positive or negative attribute before further boolean operations are carried out.
	Arched Opening in a Wall. Here a Positive cylinder is placed on top of a Positive stretched cube and both are grouped together. The group is given a Negative attribute. The wall is another stretched cube with a Positive attribute. Make sure the wall is narrower than the Negative group.
The image on the left shows the two objects before grouping the wall and the door group, the one on the right shows the result of grouping the two together. This could also be achieved by setting the cylinder and first cube both to negative and grouping the three individual objects together.
	Wine Glass Bowl Here a Positive sphere has a smaller Negative sphere centred inside it and both of them are grouped together. The group is made Positive. A negative cube cuts off the top to form the rim. Below left shows the arrangement before grouping and below right after grouping. At the bottom is a render of the bowl only with a glass material applied and also a finished glass with stem and base.