Blender Modeling

Introduction

Meshes	All objects in Blender are meshes, which are made of points, vertices, edges and faces.
Point	The origin point describes the location of the object. The orange dot represents the origin point. The shape of the object is built around this point.
Vertex	A vertex point is just a point. A mesh is made up of a series of these points. To create a new vertex point, in Edit mode select an existing vertex point then press Ctrl+LMB.
Edge	Edges connect vertices together. An edge connects two vertices by a straight line. Think of edges as wires that you can see when you look at a mesh in wireframe view. They are usually invisible on the rendered image. They are used to construct faces. To create an edge from two selected vertices press F.
Face	A face is made when edges and vertices combine together to form a solid surface. A face is defined as the area between either three (triangles) or four (quadrangles) vertices, with an edge on every side. Triangles are always flat and therefore easy to calculate. On the other hand, quadrangles deform well and are therefore preferred for subdivision modeling. To create a face, select three or four suitable vertices and press F.

Object and Edit Modes

To toggle back and forth between Object and Edit Mode, or Sculpt and Edit Mode press TAB.

To deselect all the vertices, edges and faces in Edit Mode, press A.

You can choose which mode you want to be in by selecting the appropriate button:

Alternatively, when in Edit mode you can switch among the options by pressing CTRL+TAB+1, 2 or 3

In Vertex Select Mode, select a vertex by RMB clicking on it. Then press G to move it.

The Limit selection to visible button:

is used to toggle whether the mesh in Edit Mode renders as a fully opaque solid, or whether the faces are slightly transparent.

To select several vertices, you have several options:

Border select-press B
Circular Select-press C
Select-press A
Invert Selection-press CTRL+I
More-press NUM+ (on Mac Laptop, hold FN, CTRL,+)
Less-press NUM- (on Mac Laptop, hold FN, CTRL,-)
Linked- press Ctrl+L
Select Non Manifold-press Ctrl+ Shift+Alt+M
Linked Flat Faces-press Ctrl+ Shift+Alt+F (Only works in Face Select Mode)

Extrude

Extrusion is the process of pulling or pushing a selected face.

To extrude a face, select it and press E. To confirm the extrusion, click the LMB. Now you can scale rotate and move.

You can also select multiple faces and press ALT +E to extrude multiple faces.

Individual

Region

Fill

F calls the Fill command to create a new face from selected vertices. You must select at least 3 vertices before pressing F to make a face from the selection. If you select 2 vertices and then press F, you will create an edge.

EdgeLoops

An edgeloop is where a set of vertices are connected in a line, or sometimes a circle. Press CTRL+R to create an edgeloop.

A purple preview of the new edgeloop is shown.

You can move this around before finalizing the move with LMB
After LMB, you can move the mouse to slide the edgeloop into place (Press 0 if you don't want the loop moved from the center).
Another LMB anchors the edgeloop into place
If you want to move the edgeloop after clicking LMB, then select an edge of the loop and press CTRL+E then select Edge Loop then Edge Slide (Edge Slide is also found in the Deform Section of the Tool Shelf)

Edge Menu

Pressing CTRL+E brings up the Edge Menu.

Pressing X brings up the delete menu. You can select edgeloop and delete an entire line of vertices.

Merging Vertices

In Vertex Select Mode, you can select any number of vertices and then press ALT+M to bring up the Merge Vertices Menu.

Joining and separating vertices

In Object Mode, you can combine separate mesh objects into one by pressing SHIFT-RMB-selecting them and then pressing CTRL+J. While you have created a single mesh, you will probably still run into trouble printing the file. Before pressing CTRL+J you should select both meshes and add a boolean modifier of type union:

Select one object then SHIFT+RMB on the second object.
Navigate to Modifiers (the wrench)
Click on Add Modifiers and select Boolean
Select Union
Set the Object to the mesh in the list that was included in the selection
Select Apply
Deselect both objects then select them both and press CTRL+J

In Edit Mode, you can split a mesh using the P key. Select faces you want to separate, press P and choose Selection from the menu.

Boolean Difference

You might want to subtract one object from another. Here is how you would subtract a cylinder from a cube:

Start with a cube
Add a Cylinder Mesh by pressing SHIFT+A. You can adjust the size on the left side:
Select the cylinder and then SHIFT+click on the cube
Navigate to Modifiers (the wrench)
Click on Add Modifiers and select Boolean
Select Difference
Set the Object to Cylinder:
Select Apply
Select the cylinder
Press X to delete
Here is the finished cube:

Sculpting

Start with a cube.
In front view move the view off center by holding down the MMB and dragging the mouse to one side. Holding down SHIFT with the MMB will move window.
SHIFT +MMB to view the wrench. This is the Modifiers tab.
Open the Modifiers Tab and click on Add Modifier
Under the Generate column (left), select Multiresolution
Click the subdivide button a few times
With the cube selected, switch to Sculpt Mode
Turn on X Symmetry
Experiment with the brushes
LMB to sculpt with them

Exercises

Using primitive shapes, piece together a character.
The Ten Cube Challenge
For any model, use ten cubes. You may stretch the cube, but it must always remain a box.
Use difference to make your models.
Sculpt something

Before Printing

Select your model
Go to Edit mode (press TAB)
Select All (A)
Select Mesh:Vertices:Remove Doubles
Press SHIFT+CTRL+ALT+M for non-manifold (water-tight)
Go back to Object Mode
You need to export your model as an .stl file. Go to File and select Export:STL(.stl)