Introduction to Blender

written Oct 2005
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ContentsIntroductionBasicIntermediateAdvancedFuturePolicyInfrastructure

1   Introduction        

1.1   Rationale        

Blender is an open source project which is used for 3D modelling with wireframe, lighting and textures up to the creation of 2D animations and 3D formats such as VRML and DirectX. The program is available on Windows, Linux and Mac. Blender uses OpenGL for all its interface.This makes it one of the most widely accessible and functional 3D tools available. However, as with all 3D, there is a steep learning curve. This tool is used commercially for advertising. It appears that the NZ Election Logo man might be a blender model/animation.

OpenGL does not integrate seamlessly with the various Windows systems and Blender has its own dialogues for file access etc which look a little cludgy.

Special Note: There is a tcl interface to OpenGL - tclogl - first version just released is 0.1. This is a new widget called a tclogl widget.

Blender is extendable via Python scripts (no Tcl as yet).

This makes blender a leading beginners tool for 3D modelling. (Maya is the professional's choice commercial modelling/animation program.) While Blender is a beginners tool for 3D modelling, it is also a commercial level tool and was designed as such from the outset. This makes it a kind of one-stop shop for learning 3D modelling up to professional level. It is very complex, assumes you are familiar with a huge range of notions in geometry, colour logic etc.

There are a number of graded tutorials on the blender website(s) which should be done.

This document instead gives a summary view of blender with an aid to providing a more constructivist appraoach to using the tool. The tutorials are more monkey see - monkey do, which does not aid creativity.

1.2   Prerequisites        

You should have built objects in active worlds and possibly have even made some simple models in Modeller to use in activeworlds. You should have a good grasp of 3D essentials, including the x-y-z coordinate system, and be familiar with geometric terms such as vertex, face, edge, orthogonal, etc. You should also be familiar with 2D vector graphic packages such as Paint Shop Pro, tkdraw or CorelDraw which use bezier curves and other vector graphic objects.

2   The blender window        

The first view of blender is pretty impressive and a little overwhelming. It is actually three windows stacked vertically. Each window has a header which changes shade when that window has mouse cursor focus. The header can be moved around the windowframe. The leftmost icon in the header is a pulldown icon menu from which you can select 1 of at least 12 window functions. On starting Blender you will see that the top window is the user preferences window. The middle is the 3D View and the bottom is the Button Window.

The User config window is usually kept collapsed. You usually only need to access the Menu Buttons in the Header such as File and Help.

You can see from this layout that you can have the buttons at the top if you want. Select the button view for the middle window. You can see that it reproduces the bottom window but on a different scale. This is because Blender is written using OpenGL graphics over the whole of the program, not just the editing window. The whole layout including subwindows are in OpenGL.

If you right-click on the Header you can see that you can have it at the top or bottom of the window, or you can hide it (and lose it?).

3   Operating System <-> Blender        

Because OpenGL does not integrate with the OS windowing cleanly, Blender operates a little strangely as a program. It usually takes up the whole screen and may not have a title bar. Its File Dialogues are specially written and do not have native look and feel and are somewhat basic. Typically when you are doing a tutorial you want to move between Blender and a webpage but this may not be easy to do. The best way I have found is to use F12 which invokes the rendering engine which outputs the current rendered image into a window which is in the OS. This invokes the OS windowing system and you can get to other windows from there on the desktop menu bar. Focusing on Blender hides the render window again, as well as the window taskbar, so use F12 again to bring it back with a new render.

Blender appears to work as expected on Windows.

If you focus on the render window you will see that you can pan around the 2D image using the mouse.

Ctrl-Tab is supposed to give access to the taskbar, but this doesnt always happen on all operating systems.

4   Navigating the viewport        

4.1   The numeric keypad        

The 3D viewport is the main working area in blender. It is sellected from the pulldown icon menu at the left end of the Header. As usual with anything 3D just moving around can be a tricky thing to learn. Fortunately we dont have to go anywhere as we are focused on the objects in front of us, but it is still complicated. The numeric keypad (with numeric lock on) provides the base orthogonal views: 1 the x-z (across and up, Front view), 3 the y-z (back and up, Side view) and 7 the x-y (across and back, Top view) . The number keys 2 4 6 8 turn the viewport around an axis by 15 degrees (6 tabs per quarter like activeworlds) . 2 and 8 around the z axis, 4 and 6 around the x axis.

+ and - zoom in and out.

5 switches between orthogonal and perspective views.

Ctrl-1 is the back view, Ctrl-3 is the other (left side view), Ctrl-7 is the bottom view.

0 is used for a camera-eye view. This gives a perspective view even though it does not show perspective status=on.

"." is used for a closeup of the currently selected object(s). It does not toggle.

"/" gives you a close-up view opf the scene and toggles back to the previous view.

Using these close-up views, you can get too close to the objects. Enter on the numeric keypad gives you a stanard distance back from the model.

4.2   The mouse roller/middle mouse button (MMB)        

Rolling the mouse roller zooms in and out. Pressing the MMB (roller) and moving the mouse rotates the axes. Use 1, 3 and 7 to get back to a standard view.

Shift-roller pans up and down. Ctr-roller pans right and left

4.3   Summary        

The View Menu on the 3D Edit Header gives a list of navigation functions and checks the active states. You will see a few other navigation options there.

In the main, Navigation is done using the numeric key block or the mouse roller, with the aid of Shift and Ctrl keys.

If you go to the button window at the bottom you will see that similar navigation rules apply but with some differences. Ctrl-Roller zooms in and out while Roller pans left-right and Shift-Roller pans up and down. (So much for consistency).

5   3D View        

As noted above there are about 12 different pane types but the main one we use is the 3D View. But this view has 5 different modes which you can see on pull down list on the Header. The two main Modes we use are Object and Edit. Tab toggles between these two.

Object Mode is used for selecting whole objects and performing functions on whole objects. It is also used for defining relationships between objects (parent-child). It is used when adding new objects to the scene.

Edit Mode is used for editing the vertices of an object. In edit mode you can see vertices.

6   Selection        

Selection in Object mode selects objects. Selection in Edit mode operates in 3 modes, Vertex, Edge or Face. The Three icons towards the right end opf the header allow you to select the selection mode. Most of the time you are manipulating vertices.

The a key deselects all, or selects all if nothing is selected.

Right mouse click close to the item to be selected selects one item. To select more hold down Shift and select with right mouse click (RMM).

The b key is used for a box group select. This selects within the 2D box you draw with the mouse but with infinite depth, the box is bottomless. It is important to remember this property when you want just 1 point on the front face plus the points hidden behind it.

There is also a lassoo selection tool.

7   Textures        

Textures can be mapped over objects in a manner similar to activeworlds, CorelDraw etc. A computer generated image can be used. Like CorelDraw and other 2D programs there are programmable plugins for this. They come in two parts, the basic texture, which each has its own particular parameters and a modifying texture again with parameter interfaces. The modifying texture tends to be monochrome.

You can also use an image as a texture.

In addition there are 3D particle and wave textures. Select the object to be textured in Object Mode and select the Object Button Panel (F7). The third panel has an Effects tab. Create a new effect and select Particle or Wave. These bring up their own dialogues which are quite complex.

7.1   Particle Textures        

Experiment with Particle textures on the simple cube. Once the Particle Texture Dialogue box is up press F12 and see what you start with. The 8 points of the cube are lovely fuzzy white balls. What is happening here is that the vertices have 1000 (the Total dial) particle strands coming out of them. Adjust the Total to 8 and you get 8 fuzzy white particle points.

Make Tot: 50, Step: 1, Life: 12 and look again. You still have 8 fuzzy balls. The other 42 are superimposed om the vertices. Check the Face button which distributes the particles over the faces of the cube. This gives a loose cottonwool effect. Reduce Life:1 and you get a soft ephemeral star effect. In crement Step and watch the balls get softer. Increment Life and watch the balls get a little more definite. The Vector button limits the balls into a line. VectorSize tightens the vector line. Norm: gives the particles length and this is where things get hairy. Set Tot: 200 Step:1 Life:12 VectSize:0.9 Norm:0.2 and you get a lot of fuzzy spikes. The Force x y z counters make the particle streams bend in a direction. Try Force z:-0.4.

As you can see there are a lot of parameters to adjust. It is best to cruise around and when you see a nice effect to give it a poetic name and save it. This is as much Art as Science.

But this is not the end of Particle Texture. By moving back to the Shading button panel, Click on Shaders and Halo and play around with the settings here. Many special effects can be found. Halo effects can produce feathers and animal skins.

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