Polygon Modeling: (Inside Softimage Chapter 7) *** See Figure 7.13 fig7.10.addedge.jpg The polygon from Figure 7.11 with edges added between the new vertices. Edges can only be added within a single polygon. This means that if the vertices you want to connect belong to different polygons, you cannot add an edge. You have to find an edge between the two vertices and add an intermediate vertex, making two more edges to connect the points. Using the middle mouse button allows you to connect a series of vertices with shared edges. The right mouse button removes edges, which removes the polygons dependent on that edge, and may create a hole in your model. (d)Adding Polygons to a Mesh The Polygon]Polygon command has the same functionality as the Attach mode of the Draw]Polygon command, and it can be used by itself to either fill holes left in polygons or add new polygons that share edges with the current mesh. Polygons can only be added to open edges, so that no more than two polygons can ever share an edge. You can show the open edges of a mesh with the Show]Edge flags command (see Figure 7.14). After executing the Polygon]Polygon command, pick at least two vertices to attach a polygon. If you are adding a new polygon, then click somewhere off the mesh to place a new point in space, and continue to place new points until you have defined the polygon you want. To complete the polygon, click the middle mouse button. *** See Figure 7.14 fig7_12_edgeflag.jpg A polygonal mesh with holes showing the edge flags. If you are patching a hole in a polygon, continue to select only existing vertices until you have plugged the hole. Then use the middle mouse button to complete the polygon. (c)Take a Shortcut: Working from a Primitive Now that you know how to start from scratch, making your own objects out of nothing but ambition and the Polygon menu cell, I should tell you that it is almost always easier to start out with a simple geometric polygon primitive and use the polygon duplication and transform tools to create the object you need. From one polygon, you can make many by duplicating the original and transforming it in a number of interesting ways. Many types of angular, precise looking objects can be easily created this way, such as buildings, machines, ovens, and all manner of other manufactured devices. But before we dive in, first a word about the polygon transformations and the Polygon Local Coordinate system. (d)Polygon Transformations and Local Coordinates When you are in the POL (polygon) mode, remember that only the selected polygons are acted upon by the Transformation menusÕs cells and a number of other commands, including Duplicate and Delete. This means that the object stays as it is, and only the pink polygons colored pink are translated, scaled, rotated, and so on (see Figure 7.15). Don«t forget to return to OBJ mode when you want to work on the entire object and not just the individual polygons. *** See Figure 7.15 fig7_13_poltrns1.jpg A polygonal object with selected polys translating on their own axes.