Essential Blender- P7 ppsx

With your selection of vertices made as you like, press the "New" button in the Vertex Groups panel.. Once you have entered a name, click the "Assign" button to assign the selected verti

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

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

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

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 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:

Shift-Figure MMT2.03: The remaining quad with its lower left vertex at the origin

Notice that the lower right vertex is exactly at the intersection of the red and blue axes (x and z) In order to move the quad exactly onto that, hold down the Ctrl key while moving in Grab mode With the Ctrl key down, the movement snaps to a grid, allowing you to easily put the lower left vert exactly on the origin

Here's an alternate trick for doing precision movement Undo (Ctrl-Z) the translation you just performed Now, press the G-key to enter Grab mode, followed by (and type exactly what is inside the quotes) "x1" Then hit Enter Now, type "gz1" and hit Enter The quad should have moved one full unit to the right, then one full unit up Blender accepts numeric keyboard input

in transformation modes Obviously, you won't use that trick all the time, but it's excellent, for example, if you want to move something along a single axis for a specific distance, or to scale something to exactly twice its original size

You might have noticed in the original image that the faces of the pillars below the bridge are symmetrical This will allow you to take advantage of one of Blender's most powerful mesh tools: modifiers

Click the "Add Modifier" button, then choose "Mirror" from the popup menu Some new controls will appear You will also notice that in the 3D view, the quad has been mirrored along the X axis This mirrored copy is a "live" effect, and can be reconfigured at will in the modifiers panel

symmetrical both left to right and top to bottom, you'll add a second mirror modifier

Click "Add Modifier" again, and choose "Mirror" Another mirror modifier appears in the Modifiers tab, below the first one Nothing happens in the 3D view This is because the

second modifier is set up exactly like the first, creating a second copy mirrored along the X axis, overlapping the first You want this copy to be top-to-bottom, so change the axis of the second modifier by clicking its "Z" button When you do that, you see the quad now mirrored along two axes, like the next illustration

Another way to create this modifier would be to press the "Copy" button on the original mirror modifier, making a duplicate below the original that can be changed to suit your needs

MMT2.05: Notice the ghosted items to the left of and below the main mesh

Finally, turn on the "Do Clipping" option in both modifiers This will prevent any vertices you move from crossing the X or Z axes, which would cause overlapping meshes at the mirror

point The option "clips" any transformation that crosses its axis When you have the

modifiers set up properly, the panel should look like this:

MMT2.05.1: The Modifiers panel with both mirror modifiers in place

Now, with all four vertices still selected, use the G-key again, and see how things function with the modifiers in place Moving the quad away from the mirrored axes does the same for all four copies Moving it toward the axes actually changes its dimensions as the "Do

Clipping" option keeps the vertices from crossing the axes Move it around until it looks something like the next illustration, then LMB to accept the transform

MMT2.06: Try to move the quad around until it looks like this

Subdivision

One way to begin adding detail to a mesh model is through subdivision Subdivision is simply dividing faces like your quad into smaller faces that take up the same space Blender has several tools for dividing faces and edges, and you'll use one of them now

With all four vertices of the quad selected, press the W-key to bring up the Specials menu This menu contains a lot of common mesh modeling operations In the menu, LMB on

"Subdivide Multi", and accept the default "Number of Cuts: 2" that appears The quad is divided twice in each direction, leaving you with something like this:

MMT2.07: This quad has been subdivided

As was mentioned before, some screenshots, like the previous one, are in wireframe mode, and may not match your screen You can toggle between wireframe and solid modes by using the Z-key

We would like some of those faces to form the basis of a nice border for your pillar, but you need to adjust them a bit first

Working with Edges

Up until now, you've been working with vertices It is also possible to work directly with edges (the lines that connect vertices) or faces (the filled spaces defined by edges) On the 3D header, click the Edge button, as shown in the illustration:

MMT2.08.01: These three buttons choose different select modes

In the 3D view, the vertices disappear You were working in Vertex mode before, but now you are working in Edge mode All the same selection tools (RMB, Border, Lasso, etc.) apply

to edges that applied to vertices and objects, but you get a few new and very useful tools as well

While holding down the Alt key, RMB on any edge in the quad The entire line of edges associated with the one you clicked is selected This is called Edge Loop selection Now, Edge Loop select (Alt-RMB) one of the interior vertical edges

Press Ctrl-E, and a menu titled "Edge Specials" appears From that menu, LMB select "Edge Slide" The edge loop you have selected enters a special kind of grab mode that allows you to slide it between the edge loops on either side As with any other transform mode, LMB accepts the change and RMB cancels

Using a combination of Alt-RMB select and the Edge Slide tool, try to select and move the interior edges up and to the right so that your model looks like this: