An arbitrary number of MODEL section statements may be grouped together through the use of the brace bracket characters, { and }. The start of the group is marked by the opening brace, {. The end of the group is marked by the closing brace, }. All statements between the braces are treated as though they were one single statement. Transformation statements (rotate, translate and scale) only have effect within the group. Instances and literals create objects in the scene. Assignments effect the value of variables, which retain their values across the boundaries of the group. All other statements behave in their normal manner. Groups may be nested to any degree.
Groups are useful for two purposes. First, groups allow hierarchies of objects and transformations to be constructed. When used in this sense, they are identical to the groups found in the interactive package. Second, groups are useful for ex-tending the range of effect of if statements and for statements. This usage of groups is not presently available in the interactive package. It is, however, vary similar to syntactic constructs in “C” and other programming languages.
