Essential Blender- P1 pdf

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Chapter 1: An Introduction to 3D A rt

By Roland Hess

If you are completely unversed in 3D art, then this introduction is for you If you already know what you're doing and are just using this book to get yourself up to speed with Blender, then skip right on to Chapter 2, The Blender Interface (Of course, if you did that you would miss out on a fantastic analogy for 3D art that might give you inspiration some day when your mouse just doesn't want to do its thing and all you can think of are chrome spheres and

checkerboard planes.) Please note that the screen shots and references to Blender in this chapter are not tutorials - they are simply general examples of what can be done You won't find step-by-step instructions on how to recreate them We'll get to all that later

Taking Pictures of Tiny Little Houses

3D Art is little more than building a model and taking a picture of it

Image:Dummy.png

Figure 1.1: A street scene created with miniatures and raw materials

Did you ever build a little setup with toy houses, put miniature figures in it, maybe snap off twigs and bits of bushes and stick them in clay to look like little shrubs? Did you take a

picture of it, close enough to the ground to try to make it look like the town was real? Did you spend countless hours in your room as a kid trying to make the whole thing as realistic as possible, while all the other kids taunted you and called you the "Hermit King?"

Okay, maybe that was just me

But that, minus the taunting, is the essence of 3D art Creating and taking pictures of models Admittedly, 3D Art is a much deeper topic than that, but that is where we'll start

Raw Materials

If you were going to build a diorama of a downtown street, what would you need? Boxes, for the buildings A knife or scissors to cut windows and doors, or maybe just a marker to draw them on, depending on how fancy you want to get Colored paper and odd bits of cardboard to make things like the road, the sidewalks and curbs, the trash bins and benches Maybe if you were feeling lazy, you'd just buy a couple of miniature benches and street signs from a hobby shop If you were feeling especially clever, you might make a mixture of glue and colored sand to simulate roofing material You'd need a couple of clippings from live plants to stick around as trees and bushes

Image:Dummy.png

Figure 1.2: Some of the raw materials you would use to build a diorama

If you had all of that, you could build yourself a nice little street scene

When it was built, and it looked the way you wanted, you could set a digital camera on the ground, frame up the picture in the viewfinder and snap away You could move the camera to get shots from different angles If you really wanted to, and you had built things properly, you could have some action figures taped to sticks running around the place while one of your friends recorded it with her nice digital video camera

Working in computer generated 3D art is almost exactly like this, except that you don't risk slicing the end off your finger with an artist's knife

First, you build your model Then, you paint it Then you arrange all your models where you want them and start snapping pictures

Building Models

In 3D art (commonly referred to as CG - Computer Graphics, CGI - CG Imaging, or simply 3D) almost all models are built from triangles It may not seem so at first, because many modeling tools let you work with quadrangles, curves, bevels, mathematical surfaces and a bunch of other stuff I'm not even going to mention But in the end, it's all triangles Why, you might wonder? Remember all the times that you've smacked your computer and said "stupid machine"? Well, you were right

Figure 1.3: This is a triangle

Computers are stupid Way down in their guts, all they understand are triangles, so that's what you're stuck with Fortunately, computers are really good at calculating and drawing triangles, and there are a lot of very smart people out there (like the people who wrote and maintain Blender) who know how to build tools that make it so easy for you to work with triangles that you often don't even realize that's what you're doing

And so, from triangles, you will see that you can build a quadrangle

Figure 1.4: These are quadrangles

With triangles and quadrangles (quads, for short), you can build anything you like A box for

a diorama street scene A monkey Something beautiful

Figure 1.5.1: A simple 3D model, showing its triangle construction on the right

Figure 1.5.2: A monkey head (Suzanne, Blender's mascot), showing triangles

Figure 1.5.3: Detail of "Miracle" by Robert J Tiess

The tools that have been developed to help you work with triangles let you move their

corners, their edges or the whole thing at once They let you duplicate them, smooth the angles between them, split them apart and weld them together They let you push them around like clay, order them in rows or rotate them in space around an arbitrary axis

Let's take a look at some of the shortcuts and tools that are available to you when building 3D models (The following is not a tutorial, so we don't recommend trying to do this yet It's just

a sample of the kinds of things you can do.)

Modeling Tools

In Blender, as in all 3D graphics applications, you have access to a number of different very basic models to help get you started

Figure 1.6.1: The primitive shapes accessible through the toolbox

Figure 1.6.2: Some of the available primitive shapes

From this beginning, you can use the other tools to grow, shape and refine your model If, for example, you wanted to take that cube and build a 3D plus symbol out of it, you could use one

of the most popular modeling tools available: the Extrude tool

Figure 1.7.1: A standard cube, with the top face selected

Figure 1.7.2: The top face, extruded upward

Figure 1.7.3: Two of the sides and the bottom face selected

Figure 1.7.4: Those faces extruded, to form a plus (+) symbol

Now, you might want to change the shape of the plus symbol, making each arm grow in the middle To do something like this, you would use another popular tool: the Loop Cut tool

Figure 1.8.1: Loop Cut tool in use on the top arm

Figure 1.8.2: Loop Cut made around the center of each arm

Figure 1.8.3: End and center faces scaled down to make a nice new shape

In the last illustration, you shrunk (scaled down) the quads on the ends of the plus, and the ones that made up the center, giving you a nice new shape Now, you might think the edges are too sharp, so you use a combination of the bevel tool and the smooth tool until your model looks like this:

Figure 1.9: A beveled, smoothed plus symbol

Okay, you might be thinking, I only see a few triangles there

Figure 1.10: The plus symbol with triangles made visible

Ah There they are

Blender, like most 3D packages, offers you dozens of modeling tools that you can combine in

an almost infinite variety to produce any kind of model you can imagine Try doing that with

a cardboard box

Materials

Let's go back to your little cardboard box model of the street If you just stick a bunch of plain boxes in a row, it's not going to give a very good illusion of a street To make it better, you need to make the boxes look more realistic Let's say that you want the Post Office to look like it's made of brick You have some options: 1 draw bricks directly on the box with

markers or paints; 2 find a picture of a brick wall, cut it out and glue it to the box; 3 make an

actual brick-like surface out of glue and red sand, apply it to the box, and painstakingly carve the mortar lines into it

Of course, to do a good job, you'd have to finish the rest of the box Paint trim around the door and window holes Maybe cut and fasten rectangles of clear plastic to make windows Come up with something neat for the shingles For a nice little detail, you can draw a little sign on the door that displays the office hours

So, how does this translate to 3D? In 3D, you define and apply different materials to your models, just like you would for your diorama

In Computer Graphics, you can get your materials in a variety of ways First, you must tell the computer what kind of properties you want your material to have: should it be shiny or dull? Rough or smooth? How should it react to light hitting it from different angles?

All of these questions are answered by using different Shaders In Blender, you can choose from a variety of shading models, each suited to slightly different tasks

Figure 1.11.1: Ball with Lambert shading Basic shading model

Figure 1.11.2: Ball with Oren-Nayer shading Good for rough surfaces

Figure 1.11.3: Ball with Minnaert shading Good for velvets and cloths

Figure 1.11.4: Ball with Toon shading Simulates cartoon-style coloring

Once you've chosen the basic properties for your material, you move on to defining things like colors If you just want the whole thing to be a uniform color, it's pretty simple If you want to get more complex, though, say, to make your material look like bricks for example, you need to add Textures And just like texturing a diorama, there a number of ways you can obtain digital textures

You could use a digital photograph of a brick wall You could use Blender's texture

generation tools to make a simulation of brick You could use Blender's 3D painting tools to paint bricks directly onto the surface

Figure 1.12.1: Rendered wall using photo texture map

Figure 1.12.2: Rendered wall using procedural brick texture

Figure 1.12.3: Rendered wall that has been painted on directly

Of course, there are a few more things to worry about than just that You have to tell Blender how to orient the texture on the model, so things look right

Figure 1.13.1: A bad angle and scale for this texture

There are other properties and things that you can do with materials, such as defining

transparency, reflection and bumpiness You can even use the texturing tools to affect settings other than color: your brick texture could be used to define brick-shaped areas of greater or lesser transparency, different levels of shininess or bumps

Figure 1.14.1: Transparency map

Figure 1.14.2: Specularity map

Figure 1.14.3: Bump map

Thus far, you've made your models and told Blender how you want them to look by defining and applying materials There's one more thing you need to do before you start taking

pictures

Lighting

You've no doubt seen model railroad displays of varying quality, often at a science center, a museum, or in your weird uncle's basement One of the things that makes a model set come to life is proper lighting There is a model railroad display in the Carnegie Science Center in Pittsburgh, Pennsylvania that covers over four hundred square feet The lighting of the

miniatures is impressive as each street lamp, railroad crossing, street intersection and building

is lit with painstaking detail Hidden lamps help to make different sections appear to have different seasons Other lamps and miniature interior lights cycle to simulate day and night

Lighting can make or break a scene Great lighting can make the most simply built and

textured model look like a real physical object, despite its other deficiencies Bad lighting can lay waste to hours of careful modeling and texturing work