Blender 3D: Noob to Pro/Meshes and Edit Mode
|Applicable Blender version: 2.63.|
A mesh is one of the most important and frequently-used object types in Blender. While there are other types of objects that can be used to model parts of a model or scene (text, NURBS patches etc), they often get converted to meshes at some point anyway, because it is the object type that offers the greatest amount of detailed control. And as it happens, Blender offers more functions, both built-in and available as addons, for dealing with meshes than for any other object type.
Edit mode is the mode in which you make changes to the internals of the active object. Not every object has an Edit mode (e.g. cameras don’t), and the details of what you can do in Edit mode naturally vary between the object types where it is available. This module will specifically cover Edit mode for mesh objects.
What Is a Mesh?
A mesh is made up of one or more vertices; each vertex is just a point in space. A pair of vertices can be joined by a straight line called an edge, and a complete loop of edges can be filled in to form a face.
It is the faces that make up the visible surface of the object: the edges and vertices are essentially geometrical scaffolding necessary to hold the object together.
A face must have three or more sides (edges). In versions of Blender prior to 2.63, only three or four sides were allowed, so faces had to be triangles or quadrilaterals (usually abbreviated to quads) respectively. In 2.63 with the introduction of the BMesh architecture, this restriction has been lifted, and you can have faces with 5 or more sides, but particularly when constructing a model for animation purposes, you will usually find that things work best if all faces, as far as possible, are quads.
Blender’s Object-mode “Add” menu (+ ) contains a Mesh submenu with a whole collection of pre-made mesh objects. Think of these as starting points; they can make it easier to construct your own objects by modifying something that is approximately of the form you want, instead of having to construct a mesh entirely from scratch.
Introduction to Edit Mode
Open a new Blender document. Hide the manipulator if it is visible (+ ). You should be in Object mode. Click with on the default cube to ensure it is selected and the active object.
You can switch modes using the mode menu, as you previously learned. However, because switching between Object mode and Edit mode is such a frequent operation, it has a keyboard shortcut:. Do this now, and you should see the appearance of the cube change, as shown at right, and the mode menu should also update; press again, and you should be back in Object mode. Press once more before continuing, to ensure you are in Edit mode.
Note the following features of the cube, and how they relate to the description of a mesh above:
- The dots at the corners are the vertices.
- The lines joining them are the edges.
- The filled areas bordered by the lines are the faces.
In Edit mode, the header of the 3D View window changes to show these selection-mode controls. If you hover over each of the buttons in the group of three, you will see that they respectively represent vertex-select, edge-select and face-select, and that you can shift-click to enable more than one at once.
In vertex-select mode, you select a single vertex by clicking on it with, and select more than one by shift-clicking on additional ones with . Shift-clicking with on an already-selected vertex will deselect it. Pressing will select all vertices if none are currently selected; otherwise it will unselect all vertices.
Edge-select mode works in a similar way, except with edges instead of vertices. And similarly face-select mode with faces.
The single button just to the right of these three is titled “limit selection to visible”; when it is active (the default), the mesh object being edited is displayed as opaque, which means that vertices, edges or faces on the side away from you are hidden and cannot be selected. Click this button, and the object becomes translucent, allowing clicking through front faces to select parts of the mesh behind them.
Another useful display mode for working in the 3D view is wireframe, which can be selected from the Viewport Shading menu or toggled with the key. In this mode, the faces become transparent, almost invisible, and the edges and vertices are displayed more prominently.
Here is what these various selection and display modes look like in combination: in the first row, a single vertex is selected; in the second row, a single edge, and in the third row, a single face. In the first column, limit-selection-to-visible is enabled; in the second column, it is disabled, and in the third column, wireframe mode is enabled.
You can use+ to select multiple things, and + to invert the selection, just like in Object mode. Only here the “things” are vertices, edges or faces, depending on the selection mode in effect. The active (last-selected) part is shown in white, while the rest of the selection (if any) is drawn in the usual orangey-yellow colour.
As already mentioned above,works in a similar way to Object mode, only instead of applying to everything, it applies to all parts of the object being edited.
, + and + work in an analogous way to their behaviour in Object mode. Again, instead of applying to everything, they apply to all parts of the object being edited.
Remembering What’s Hidden: If you switch out of Edit mode with some parts hidden, they will reappear, then disappear again when you re-enter Edit mode. So each object remembers what was hidden when you last edited it.
Local Versus Global View
You can toggle local/global view in Edit mode, as you can in Object mode. However, instead of narrowing the view to one or more selected objects, it narrows it to just the object being edited.
Border Select (Box Selection) & Circle Select (Brush Selection)
and work analogously to how they do in Object mode, to select multiple things by drawing a box or by “painting” over them.
Select More, Select Less
Edit mode has some additional selection capabilities. To demonstrate them, let’s mess with something other than the default cube, for a change.back to Object mode, and delete the cube. Now add ( + ) a Grid object instead. into Edit mode, and you will see, that the grid is made up of 9×9 faces, or 10×10 vertices. Initially they will all be selected; use to unselect them, then to brush-select a few vertices in the middle. End brush-select mode with or . Now watch what happens to the selection when you press + (select more); additional vertices adjacent to those already selected are added to the selection. Now try + (select less), and you will see that the vertices on the edge of the selection are removed from it.
Manipulator, Transformation Hotkeys, Pivot Point
All these are available for use in Edit mode as they are in Object mode, but not the “Manipulate center points” button.
Note that scaling vertices scales the distances between them; the vertices themselves have no size, so they do not get larger or smaller.
When trying to produce more natural, organic shapes, moving vertices one by one gets tedious. To produce smoother-looking shapes, you need a mode where, instead of a sharp distinction between selected vertices which are moved and unselected ones that remain where they are, there is a more gradual transition from one to the other, where unselected vertices close to the selection also get some movement.
This is where proportional editing comes in. If you look in the “Mesh” menu, you will see two submenus, titled “Proportional Editing” and “Proportional Editing Falloff”. The former turns the mode on and off, the latter controls the choice of falloff function. There is also an icon for it in the header of the default 3D view next to the layer selection. Pressing will switch between Enable and Disable.
The “Proportional Editing” submenu has 3 options: “Disable”, “Enable” and “Connected”. Do you still have the Grid object you created in the “Select More, Select Less” section above? If not, add a fresh Grid object. Switch to Edit mode, and ensure that just a few vertices in the middle are selected. Enable proportional editing, and now useto move the selected vertices. You should notice 2 things:
- unselected vertices near the selected ones also move, and
- there is a white circle enclosing all the vertices that undergo any movement.
Try using the mouse wheel while moving the vertices, and you will see the white circle grow or shrink, and the region of influence of the proportionality grow or shrink correspondingly.
Also try different falloff functions in the “Proportional Editing Falloff” submenu; some ensure that the mesh stays smooth and curvy, others give a more angular effect, and so on.
The third option to “Disable” and “Enable” proportional editing is “Connected”. This one makes a difference in more complicated meshes, which might have folds or concavities in them. In this situation, “Enable” affects all vertices within a particular distance of the selected ones, while “Connected” only measures the distance via connected edges, rather than directly through space. This lets you move one part of the mesh without affecting another part which might be located nearby purely as a result of a fold.
Of course, proportional editing works with scaleand rotate operations as well.
Now, let’s try deleting parts of a mesh. This is the menu that comes up when you pressor when editing a mesh; we will concentrate for now on the first three items.
First of all, go into face-select mode. Select just one face of the default cube, press the delete key, and select “Faces”. As shown in these screenshots, the selected face should disappear.
Use+ to undo your previous deletion. Now go into edge-select mode. Select just one edge this time. Press delete again, this time select “Edges”. As the screenshots show, the selected edge disappears, but the faces bordering that edge also disappear. Faces cannot exist without their bordering edges!
Use+ to undo your previous deletion again. Go into vertex-select mode. Select just one vertex, make sure it’s the one closest to you so you get the best view of the effect. Press delete, and select “Vertices”. Not only does the selected vertex disappear, but also the edges connected to that vertex—edges cannot exist without their endpoint vertices. And since those edges disappeared, the faces that were depending on them to be their borders had to be deleted as well.
So, to recap:
You can undo your last Edit-mode operation with+ , and undo your undo with + + , similarly to Object mode. However, Edit mode maintains its own undo stack, separate from the Object-mode one; to undo/redo an Edit-mode operation, you must be in Edit mode, not Object mode.
Back to the default cube, and Edit mode. Ensure you are in vertex-select mode, with nothing selected. Left-click with the control key down (+ ) somewhere near the cube. Do you see a little orangey-yellow dot appear where you clicked? You just added a new, unconnected vertex to the mesh.
Undo your addition (+ ). Select an existing vertex with . Now + to add a new vertex again, and you will notice that it is connected to the previously-selected vertex by a newly-added edge as well. Since the newly-added vertex is now the selected vertex, doing + again at another position, and so on repeatedly, lets you construct a whole chain of new edges in this way. But what good are edges and vertices without faces?
To construct a face, you need a closed loop of edges. To close a loop of edges, select all the vertices in the chain, and press; this will add another edge joining the first and last vertex into a complete loop of edges, and at the same time it will fill in the loop with a new face.
Alternatively, if you just wanted to close the loop without filling in the face, then select only the first and last vertex in the chain before pressing; since only two vertices are selected, this will not construct a new face, it will only add an edge joining those vertices.
You can also extrude entire new sections of mesh with a single click in this way. Try selecting two adjacent corner vertices of the cube (i.e. ones joined by an edge). Now+ near to them, and you will see you’ve created two more vertices, joined to the previous two by a new face. + again, and you can construct a whole sheet of new mesh in this way.
Undo all your additions, and get back to the pristine cube. Now select all four vertices of a single face.+ near to your selection, and now you have added four new vertices (corresponding to the original four you selected), plus a new face connecting them, plus four new faces connecting them to the original four. (You may not notice it, but the original face formed from the original four vertices has been removed as well.) Another + does the same thing again. So with just a few clicks, you started with a cube and ended up with something (see at right) that is starting to resemble—who knows? A square-cross-sectioned piece of somewhat wonky-looking pipe, perhaps?
It is possible to remove vertices without leaving holes behind in the mesh, by merging two or more vertices into one. Select the vertices you want to merge, and press + ; a menu will popup with some options, including whether to position the resulting vertex in the middle of the ones being merged, or at the position of the first or last one you selected. The resulting vertex inherits all the edges that were connected to the vertices being merged, as well as the faces connected between those edges.
Alternatively, sometimes an operation might create duplicate vertices in exactly the same positions, or very close together. You can merge these en masse by ensuring you have selected all possible candidate vertices (e.g. the whole mesh), bringing up the Vertex Specials menu () and selecting the “Remove Doubles” item. Look for a message to flash up briefly in the Info window, saying “Removed n vertices”; if n is 0, then nothing was done. But if you look in the lower left of the Toolshelf, you will see a “Remove Doubles” panel has appeared, with a “Merge Distance” slider that governs the maximum distance allowed between vertices that are merged; change this value as appropriate (either by clicking on the left- and right-arrows, or by clicking and typing in a new value and pressing ), and the Remove Doubles operation is immediately redone, and a new message will flash up indicating how many vertices were removed this time. Simply keep on adjusting the value until you are satisfied that you haven’t removed too many or too few vertices.