Copyright Goodheart-Willcox Co., Inc. Chapter 17 Materials in AutoCAD 473 Adjusting Material Maps Adjusting Material Maps Simply applying a map to a material property rarely results in a realistic scene when the scene is rendered. The maps usually need to be adjusted to produce the desired results. Maps can be adjusted at the material level or the object level. A combination of these two adjustments is usually required to produce a photorealistic rendering. Material-Level Adjustments Material-level adjustments involve changing the properties of the map in the material defi nition. Map properties are discussed in previous sections. Sometimes, these adjustments may be enough to get the materials looking the way you want them. Other adjustments become necessary when the same material is applied to more than one object in the same scene. If you make changes at the material level, they affect all objects with that same material. If you need different objects to have different settings, then you will have to make object-level adjustments. Object-Level Adjustments Material mapping refers to specifying how a mapped material is applied to an object. When a mapped material is attached to an object, a default set of mapping coor- dinates, or simply default mapping, is used to apply the map to the object. AutoCAD allows you to adjust mapping at the object level for 2D-mapped (texture- mapped) materials. The MATERIALMAP command applies a grip tool, or gizmo, based on one of four mapping types: planar, box, spherical, or cylindrical. See Figure 17-36. The colored edge represents the start and end of the map. For best results, select the mapping type based on the general shape of the object to which mapping is applied. Do not be afraid to experiment with other mapping types. Any mapping type can be used on any object, regardless of the object’s shape. However, only one mapping type can be applied to an object at any given time. After one of the mapping types is selected, you are prompted to select the faces or objects. You can select multiple objects or faces. After making a selection, the gizmo is placed on the selection set. The command remains active for you to adjust the mapping or enter an option. Drag the grips on the gizmo to stretch or scale the material. The effects of editing a color map are dynamically displayed if the current visual style is set to display mate- rials and textures. Otherwise, exit the command and render the scene to see the effect of the edit. To readjust the mapping, select the same mapping type and pick the object again. The gizmo is displayed in the same location as before. The Move and Rotate options of the command toggle between the move and rotate gizmos. Using the gizmos, you can move and rotate the map on the object. The Reset MATERIALMAP Ribbon Visualize Materials Planar Box Cylindrical Spherical Type MATERIALMAP Figure 17-36. These are the four material map gizmos. From left to right: planar, box, spherical, and cylindrical. The colored edge represents the start and end of the map.