Vertex Groups allow you to save selections of vertices, so that later you can reselect them easily. This is useful when creating complex models that may need adjustment later. For example: when working on a face, if you find that you are constantly selecting the same group of vertices around the nose, it would make sense to save that selection for easy access. It's important to understand that the selected vertices haven't actually been "put" into a group, though. Vertex groups just contain lists of vertices. So, there is no reason that a vertex cannot be listed in several different vertex groups. Vertex Groups are created in the "Links and Materials" panel of the Edit buttons, in the Vertex Groups section of buttons. With your selection of vertices made as you like, press the "New" button in the Vertex Groups panel. Some new controls will appear, including a naming field and popup menu button for choosing other, already created vertex groups. Figure PMD.22.1: The Vertex Group controls. The default name for the first vertex group created is simply "Group", but can be replaced with something that will help you to remember its contents better. Once you have entered a name, click the "Assign" button to assign the selected vertices to the named group. Remember that simply clicking the "New" button only creates an empty vertex group - your selection will not be saved into it until you click the "Assign" button. The other controls in that part of the panel do the following: Delete: Deletes the named vertex group. Note that this does not delete the vertices, it just removes the saved selection. Remove: Removes the selected vertices from the currently active vertex group. Select: Examines the named vertex group and selects its vertices in the 3D view. This is an additive selection, so anything that was already selected in the 3D view remains selected. Desel.: The opposite of Select. Any vertices that are selected in the 3D view, but are in the named vertex group, are deselected. Mirroring Another time-saving feature in Blender is the Mirror modifier. It allows you to only model half of a model and see it duplicated in mirrored form, creating the other half. It is useful for modeling symmetrical things, like this head as seen in the illustration below. Fig. PMD.23 Adding a mirror modifier in Blender is just like adding a Subsurf modifier: click the "Add Modifier" button on the Modifiers panel of the Edit buttons and choose "Mirror". The mirrored half will appear as ghosted lines in Wireframe mode, but will be fully solid in Solid mode. Enabling the "Do Clipping" button in the Modifiers panel will prevent any vertices you transform from crossing the center line of the mirror effect. When you have finished symmetrical modeling, pressing the "Apply" button in the Modifiers panel will make the mirrored half of the model into actual geometry that can be selected and modified independently. Loop Cut In addition to the other subdivision controls that you have learned, the loop subdivide tool allows you to quickly and uniformly subdivide all the edges that are within the same "loop". In the illustration below, you can see the cut line looping around the eye, which will allow the modeler to add crease lines. To initiate a Loop Cut, press Ctrl-R and move the cursor over the model. While moving the cursor, you'll notice that when Blender detects groups of edges that it can cut, a magenta line will appear to indicate the location of a possible loop cut. When the magenta line indicates the loop that you would like to cut, press the LMB once to begin the cut. Then, Blender will allow you to slide the cut back and forth between the outer edges by moving the mouse. You can even increase or decrease the number of cuts made along the loop by using the scroll wheel. When you have the cutting line positioned exactly as you like, pressing the LMB will have Blender make the cuts. Pressing the RMB at any point in the procedure cancels the cut. Fig. PMD.24: A new loop is being cut around the eye on the right side of the image. Edge Slide Once you begin using the Loop Cut tool to add detail to your models, you may find that edge loops become even more useful. For example: what if the cut that was made around the eye in the previous illustration fell along the center of the edges, but you had really wanted it nearer to the exterior loop? Instead of moving each edge individually, you can simply Alt-RMB select the edge loop, then choose "Edge Slide" from the Ctrl-E Edge Specials menu in the 3D view. This allows you to slide the edge back and forth between the two bounding loops. LMB accepts the slide, while RMB cancels. This tool will actually allow you to slide any selectable edge loop, regardless of what tools were used to create it. Edge Loop Delete One of the elements in the X-key delete menu we have not mentioned is the "Edge Loop" option. With an edge loop selected, using this option from the X-key delete menu will remove the edges, but join the faces on either side. The effect is as though an edge loop had never been cut there. This is a great tool for cleanly reducing the polygon count of your meshes once you have them looking the way you want. Conclusion In this introduction, you have seen the basic tools for polygon modeling in Blender and learned a little about how you can begin to work with them. If you haven't already worked through the tutorial section of this chapter, it's a good way to see this theory put into practice, and to learn a few more tricks as well. Best of luck, Kevin Braun Mesh Modeling Tutorial By Roland Hess Based on the Blender Summer of Code tutorial by Michael Worcester In the previous chapter, you learned how to manipulate objects in Blender. You've seen how to move, scale and rotate objects, as well as some ways to set Blender to different modes. But now we want you to actually edit the object itself. Blender has several modes for dealing with objects, but the two most frequently used are Object Mode and Edit Mode. In Object Mode you work with the object as a whole - you can move objects, scale them and rotate and parent them. In Edit Mode you concentrate on one particular object, and make changes to the mesh that gives the object its shape. So, what's a mesh? I hear you asking. Usually, Blender (and computers in general) represents 3D objects by a set of vertices (or points) connected by edges. Three (or sometimes four) vertices can form the boundaries of a "face". A face is just a part of a mesh that is "filled in", and will look solid when rendered. Vertices and edges do not render, but faces do. Here are some images to attempt to make this clearer. Image:Dummy.png Figure MMT.00: [no text] In Edit Mode, you manipulate the object at the vertex level. Figure MMT2.55: Where we'll be heading in this tutorial. This model is what we hope to achieve in this tutorial. In theory, you could come close to making this all in object mode, but what you need to learn is when and where to use the different tools Blender has to offer. Knowing that this is the product of experience, doing this tutorial will give you some idea of how to choose your tools. Anyway, enough about theory. Let's get down to modeling. Start up Blender (or use Ctrl-X to begin a new session if Blender is already running) and press the Z-key. The Z-key toggles between shaded mode and wireframe mode. You can switch between these two modes whenever you want to see how you're model is coming along. In this tutorial, some screenshots will be in wireframe mode and some will be in solid mode. You don't have to be there too, though. We tried to choose the best mode just to let you see what was going on in the illustration. RMB select the default cube in the center of the scene, then press the X-key and confirm its deletion. The first thing you are going to do is to create the basic shape of one of the pillars. You could do this with a simple cube, but as the pattern on each side of the pillar is identical, you are going to create one side, then duplicate it. Use the spacebar to bring up the toolbox, then select the following menu items: Add, then Mesh, then Cube. I know, you just deleted the default cube, but we want to get you familiar with using the toolbox. Figure MT2.A: The toolbox, about to add a cube. You may remember from the previous chapter that when you add a new object, that object begins its life in Edit mode. You should be able to see 4 yellow dots at the corners, which are called vertices. A yellow vertex means that it is currently selected. Press the A-key and watch all the vertices turn pink. (This is also the case for edges and faces.) To recap, just as the A- key toggles select all/deselect all for objects, it does the same in Edit mode, only with vertices. Figure MT.04: The cube in Edit mode. Selecting Vertices There are several ways to select vertices in Blender. - RMB. Just like object mode, clicking on (or near) a vertex with the RMB will select it. Holding down Shift while RMB clicking will build a selection. RMB on an already selected vertex will deselect. - Border select. Press the B-key, then LMB drag over the area you want to select. Border select is always additive, so using it will add to the selection set you already have. - Circle select. Press the B-key twice, and the cursor turns into a circle. You are now in circle select mode. You can "paint" a selection with this circle by LMB dragging. MMB dragging deselects. The mouse's scroll wheel increases and decreases the size of the circle. RMB ends circle select mode. - Lasso select. Holding down Ctrl while LMB dragging lets you "lasso" vertices for selection. As you draw around the vertices you would like to select, a dashed line is drawn to show where you have dragged so far. Releasing the LMB completes the shape you have been drawing, then selects any vertices that fall within it. Using Numpad 7, view the cube from the top. Now, select the four verts nearest the top of the screen. There's only two, you say? Remember that for right now, you're looking straight down on the top of a three dimensional cube, and can only see two vertices because the others are directly behind them. If you like, you can rotate the view a bit by dragging with MMB just to make sure (or toggle in and out of perspective mode with Numpad-5), then return to the top view with Numpad 7. So, using any of the above selection modes, except for standard RMB, select the four vertices (which will look like only two) nearest to the top of the screen. Press the X-key, then select "Vertices" from the Erase menu that pops up. Figure MMT2.01: The cube with the top vertices selected. Just so you can see what you did, here's an off-axis view of the cube with those four vertices removed. It's now just a square. Figure MMT2.02: The plane that's left when you delete the vertices. Use Numpad-1 to change to a front view. A-key to select all the vertices (or you can Shift- RMB all four for practice), then press G-key to enter Grab mode. We would like you to move the quad to be in the exact position as the next illustration: Figure MMT2.03: The remaining quad with its lower left vertex at the origin.