TABLE OF CONTENTS To introduce the idea of 3D surfaces.
To compare 3D surface models with 3D solid drawing models.
To give examples of 3D surface models.
3D surface models will be introduced in this chapter. The 3D models described in earlier chapters have all be constructed using the tools from the Solids toolbar. 3D surface models are constructed using tools from the Surfaces toolbar (see page 174). 3D surface model drawings are constructed from 3D surface meshes. In some instances it appears as if 3D solid models are the same as 3D surface models, but in fact there are distinct differences.
The surface meshes of 3D solid models are controlled by the settings of the variable ISOLINES.
The surface meshes of 3D surface models are controlled either by the number of segments or by the two variables SURFTAB1 and/or SURFTAB2.
The Boolean operators Union, Subtract and Intersect can be used to join, subtract or intersect 3D model objects, but have no action when used with 3D surface objects.
The three 3D cubes shown in the upper drawing of Fig. 18.3 have been constructed as follows:
Left-hand cube: using the Line tool.
Central cube: using the Box tool from the Solids toolbar (Fig. 18.1).
Right-hand cube: using the Box tool from the
