Chapter 1 Introduction to Three-Dimensional Modeling 17 Copyright Goodheart-Willcox Co., Inc. snap mode refers to a spline and the point at which one curve ends and the next curve begins. The point cloud object snap modes can be used when working with point clouds. Point clouds are discussed in Chapter 15. The 3D AutoSnap markers that appear when drawing can be displayed in a different color than 2D AutoSnap markers. Set the color for 3D AutoSnap markers by accessing the Display tab in the Options dialog box. Pick the Colors… button in the Window Elements area to access the Drawing Window Colors dialog box. Select the desired context in the Context: list and then select a color for the 3d Autosnap marker element in the Interface element: list. Sample 3D Construction Sample 3D Construction The example provided here illustrates how you can move from a layout sketch to an exact 2D drawing with parametric constraints, then quickly extrude the object into a 3D solid model. Techniques illustrated here are discussed throughout the book. The object shown is the plastic housing for a 24/15-pin cable connector. The fi nal rendi- tion of this object would include internal cutouts, rounded edges, and holes, but is not shown in this example. Creating a 2D Sketch A 2D layout can be drawn quickly using the Drafting & Annotation workspace. In doing so, you can create a quick sketch without close attention to exact dimensions or you can use direct distance entry and polar tracking for accuracy. If appropriate, constraints can then be used to apply accurate dimensions and geometric relation- ships, such as perpendicularity and parallelism, to the object. See Figure 1-20A. In this example, only half of the object is drawn, since it is symmetrical. Then the MIRROR command is used to complete the layout. See Figure 1-20B. Converting to a Region The object is still composed of just 2D lines. Therefore, it must be changed to an object that can be converted into a solid model. The REGION command is used for this purpose. After selecting this command, you are prompted to select objects. Be sure to OPTIONS Application Menu Options Type OPTIONS OP Figure 1-19. The 3D object snaps can be set in the Drafting Settings dialog box. REGION Ribbon Home Draw Region Type REGION REG