3ds Max 2012 Bible - Kelly L. Murdock [357]
The Unfold Mapping option splits the model and unfolds it by adjacent faces into a single segment.
Arranging and grouping clusters
Within the Edit UVW dialog box is a square area that represents the texture bitmap. The goal is to use as much of this texture space as possible to ensure that the maximum amount of detail from the texture is used on the model. The various buttons in the Arrange Elements rollout help with this task.
After all the various clusters are separated from each other, the Pack Custom button packs all the clusters to fit within the texture space using the settings in the Pack dialog box, shown in Figure 33.12. This dialog box is accessed using the flyout under the Pack Custom button or using the Tools⇒Pack UVs menu command.
The Pack UVs menu command lets you combine UVs into a smaller space. Packed UVs are easy to move and work with because they use a smaller resolution bitmap. Two packing algorithms are available in the Pack dialog box. The Linear Packing method is fast but not very efficient, and the Recursive Packing option is more efficient, although it takes longer. Within the Pack dialog box, the Spacing value sets the amount of space between each segment, and the Normalize Clusters option fits all clusters into the given space. The Rotate Clusters option allows segments to be rotated to fit better, and the Fill Holes option places smaller segments within open larger segments.
FIGURE 33.12
The Pack dialog box includes settings for crunching all clusters within the given texture space.
The Arrange Elements rollout also includes a Rescale Elements button that scales all clusters relative to each other. The Pack Together button fits all clusters within the texture space without normalizing. The Pack Normalize fits all clusters and allows scaling while fitting. You can select to enable or disable rescaling and rotating, and the padding value is the space between the clusters.
Within the Element Properties rollout are buttons to create, destroy, and select groups. For each group, you can set a Rescale Priority that determines which groups are rescaled during packing. To create a group of clusters, select two or more clusters using the Face subobject mode and click the Group Selected button. The Selected Groups label identifies each group with a number when selected.
New Feature
The ability to group clusters together is new to 3ds Max 2012. •
Accessing the Unwrap Options
The Options⇒Preferences menu command (Ctrl+O) opens the Unwrap Options dialog box, shown in Figure 33.13, and lets you set the Line and Selection Colors as well as the preferences for the Edit UVWs dialog box. You can load and tile background images at a specified map resolution or use the Use Custom Bitmap Size option. It also has a setting for the Weld Threshold and options to constantly update, show selected vertices in the viewport, and snap to the center pixel.
The Bitmap Options section lets you specify the exact size of the loaded bitmap. This only affects how the bitmap is displayed in the interface and doesn't change the actual bitmap file dimensions. The Tile Bitmap option places the bitmap end to end for the specified number of tiles. The Constant Update option causes the viewport to update along with the texture map. The Show Hidden Edges option lets you make the hidden edges visible or invisible. The Center Pixel Snap causes the Pixel Snap button at the bottom right of the interface to snap to the center of the background pixels instead of to its edges.
Tutorial: Controlling the mapping of a covered wagon
The covered wagon model created by Viewpoint Datalabs is strong enough to carry the pioneers across the plains, but you can add a motivating slogan to the wagon using the Unwrap UVW modifier. In this tutorial, you add and edit the mapping coordinates for the covered wagon using the Unwrap UVW modifier.
FIGURE 33.13
In the Unwrap Options dialog box, you can set the preferences for the Edit UVWs dialog box.
To control how planar maps are applied to the side of a covered wagon, follow