[Bf-docboard] 3D Concepts and Fundamentals Chapter

[Stefano Selleri]

Ohoh :)

I'll merge this in the CVS as soon as possible :)

THanx a lot

Stefano
----- Original Message -----
From: "Jason Oppel" <pato@myrealbox.com>
To: <bf-docboard@blender.org>
Sent: Wednesday, June 04, 2003 4:48 PM
Subject: [Bf-docboard] 3D Concepts and Fundamentals Chapter


> It has been a long time since I promised to tackle the 3D Concepts and
> Fundamentals Chapter so I thought I'd show everyone what I have so far and
> hopefully get some feedback.
>
> I managed to finish the first section and most of the second (one more
> section on rendering remains unwritten).  The second section obviously
> needs some more content but I thought I'd see what everyone has to say
> about what I've written so far. :-)   Comments and criticism are welcome!
>
> Thanks,
> -Jason <Pato>
>
> Introduction
> ============
> 3D applications have never been more accessible or indeed more powerful
> than they are today.  Despite this fact most 3D modeling packages still
> cost thousands of dollars and are still well above means of most hobbyists
> and beginners to purchase.  Blender has eliminated this barrier of entry
so
> that anyone can now use a powerful professional level 3D modeling package
> as Blender is available for free.  We the authors of this book and the
> Blender Foundation are thrilled to present you this Official Blender
Manual
> which will undoubtably help you release the 3D artist lurking within you.
> By the end of reading this book you should have a firm understanding of 3D
> concepts and how to apply them using Blender.  Along the way you're also
> bound to create a some images and 3D scenes you can be proud of!
>
> While Blender's interface is quite different from other 3D applications
> you'll find that as you use Blender more frequently (called "blending" by
> Blender users) that its interface will actually make you extremely
> productive and efficient.  While at times Blender may seem daunting to
> learn (as are all 3d modeling applications) remember that it was designed
> with a professional workflow in mind and there is a pot of gold at the end
> of the rainbow.  The reward from learning Blender is that you'll be able
to
> fly around your 3D creations with astounding speed and produce impressive
> artwork at an astounding pace.
>
> As you're reading through this book try not to forget that despite all the
> magical technology behind it Blender is really just a medium through which
> to create art.  Through the hands of a skilled artist whether they're
> painting a picture, sculpting clay or modeling a complex scene in Blender
> the same artistic skills and talents of composition, proportion, color and
> light are being used and it's only the medium changes.  We encourage any
> aspiring serious 3D artists to learn and practice traditional artforms
such
> as sketching, modeling or painting.  The skills you learn in other art
> forms will make you a far better artist and give you a larger base of
> creative experience from which to use as a launching pad for your 3D
> creations.
>
> We hope that you find 3D modeling a fun (and sometimes an addictive)
> pursuit as we do.  Blender will help you develop the skills necesarry to
> develop your 3D artistry as far as your aspirations will carry you.  Blend
> On!
>
> Getting Oriented
> =================
> You may recall during your geometry and algebra classes at school seeing a
> graph similar to Figure 1 [show graph with x, y and z axis with a point
> mapped out at (1,1,0)].  The graphing system as seen in Figure 1 is called
> a Cartesian Coordinate System.  The Cartesian Coordinate System is the
> standard way that all 3D modeling applications use to define 3 dimensional
> objects (with a few minor variations).  Using this system we can describe
> any point in 3D space.  In this graph the horizontal axis (the x-axis) is
> used to describe the width of objects while the vertical axis (the y-axis)
> describes the height.  Of course we still a way to describe the depth of
> objects and that's the z-axis as seen in Figure 1.  Using the x, y and z-
> axis (commonly refered to as simply x, y and z respectively) we can use
our
> new found knowledge to define any point or shape in 3D space.  As we see
in
> Figure 1 the point mapped out is one unit to the right, one unit up and
> zero units deep.  To extend this concept to shapes we see that the cube in
> Fig. 2 [show cube with x, y and z mapped out on it] is one unit wide (x
> axis) one unit tall (y axis) and one unit deep (z axis).  Similarly you
can
> describe any object whether that object is a car, a plant or even a human
> in 3D space no matter how complex using x, y and z coordinates.
>
> Now that we have a way to plot locations and describe objects in all three
> dimensions let's take a look at how Blender handles 3D space.  Start
> Blender and press NUM1 to change our view so we're looking at our scene
> head on as seen in Fig. 3 [show standard blender startup scene in NUM1
view
> with the axis indicator highlighted in yellow].  If you look at the lower
> left hand corner of the 3D viewport you'll notice that there is x and z
> axis indicator (highlighted yellow in Fig. 3) to keep you oriented.  Now I
> hear you screaming from here that y and not z is supposed to denote
height.
>  Well, this is one of the "slight variations" I spoke of earlier.  Blender
> (and many other 3D applications) uses what's called "left handed 3D
> coordinates."  In left handed coordinates two of the axis (the y and z in
> this case) are flipped with one another. In Blender (and other "left
> handed" 3D applications) the z-axis defines height while the y-axis
defines
> depth.  Let's see if that's right.  Press the NUM7 pad to change our view
> so that we're look overhead on our 3D scene.  Sure enough the y-axis
> defines the depth of our default plane and the x-axis still defines width.
>
> Modeling Approaches
> ====================
> Just as a painter can use different kinds of paint to create a painting
> similarly as a 3D modeler you have lots of different methods you can use
to
> create your 3D masterpiece.  Experience will guide you on when to use
which
> method but we can start you on this road by describing the two most
popular
> ways of creating objects.
>
> Polygonal Modeling
> ===================
> To understand polygonal modeling you first need to know that a polygon is
> any three or four points linked together to form a triangle, square or a
> rectangle (even irregular shaped ones) as shown in Figure 4 [picture of a
> few different looking polygons in edit mode].  Each of these individual
> points (seen as yellow dots in Figure 4) is called a "vertex."  The lines
> linking each vertex together is aptly named an "edge." The art of
polygonal
> modeling at it's heart is stringing polygons together and manipulating
them
> to create more complex objects as seen in Figure 5 [picture of some
> wireframe mesh (perhaps a human body)].  As you see in figure 4 the object
> is comprised of only triangles linked with one another.  It's worth noting
> that whenever you see a model rendered in this fashion it is often refered
> to as a "wireframe mesh" or simply a "mesh" as it looks like it's made of
a
> wire mesh.  Polygonal modeling has a number of advantages as listed below:
>
> 1. Today's video cards efficiently handle polygons
> 2. blah
> 3. blah
>
> blah blah blah.
>
>
> Curve and NURBS Based Modeling
> ===============================
> blah blah blah.
>
> 1. Well suited for creating organic forms such as humans.
> 2. User defineable resolution (the degree to which curves are rendered
> accurately)
> 3. blah
>
> blah blah blah.
> _______________________________________________
> Bf-docboard mailing list
> Bf-docboard@blender.org
> http://www.blender.org/mailman/listinfo/bf-docboard