Learning to make things

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There may be certain things you already know; this is going to be directed at a novice, and if you already know some bits, please put up with them patiently, and you may yet learn something.

If you have questions about a particular expression or term, please ask (IM, or post).

1, 2, 3, here we go!

Topic 1: Colour

Colour is visible light we perceive, made up (by convention) of red, green, and blue components, often denoted in shorthand as a triplet in that order (eg. R/G/B, or R,G,B), and usually in a percentage (eg. 100%, 50%, 25%, or 1, 0.5, 0.25). When a colour has 100% of each component (1, 1, 1), it is considered fully white (as bright white as possible). If you halve each of the components (.5, .5, .5), you get grey (50% white). If you change the proportions of the components, you get "new" colours. For instance, full red, no green, no blue (1 ,0, 0) yields (you guessed it) bright red. Combine full red and full blue with no green (1, 0, 1) to get magenta (often mistakenly called "purple". Combine red and green to get... yellow? Indeed, mixing the components of light is different than mixing pigments (ink, paint, etc). That's just physics/reality. Shake your fist at God, the universe, or whatever if it makes you feel better. These "new" colours are called "hues". Now, a hue can be made in several shades; the brightness varies. For instance, bright yellow (1, 1, 0) and medium yellow (0.5, 0.5, 0) have the same proportion (ratio) of red, green, and blue, but the brightness for medium is half (you might consider adding the components and dividing by 3 to average them to determine the brightness ratio.. erm.. well, that's not really important). So, now we have hue, and we have brightness (sometimes instead called value). One thing left: saturation. When you take a full red (1, 0, 0) and start adding equal amounts of green and blue, say (1, 0.1, 0.1) then (1, 0.2, 0.2) all the way up to (1, 1, 1), the red will gradually become pinker, and then whiter, and finally fully white. Pink could be considered a "washed out" red. This "washed out" look is a result of saturation (or lack thereof). A colour that is fully saturated has as little "white" in it as possible; as a colour loses saturation, it becomes "whiter". So, you can now discuss colours in terms of red/green/blue (RGB) or hue/saturation/value (HSB) or hue/saturation/brightness (HSV). You may have seen these acronyms before. Now you understand what they mean (hopefully).

Topic 2: Alpha

If it wasn't crazy enough to have 3 components, there exists a fourth, which we often take for granted in the real world. The alpha component (or alpha channel) is also usually expressed as a percentage, and it defines the opacity (or sometimes translucence) of a colour. For instance, concrete is pretty much completely opaque (no light can pass through it); glass, on the other hand, is almost completely transparent. Some applications use a high value of alpha for opacity, and others use a low one. SL uses an alpha value of 0% for complete transparence, and a value of 100% (or 1.0) for complete opacity. Alpha is usually specified as the last component. So, suppose you have a texture that is a big rectangle of red that is half-translucent. Then its component values (including alpha) will be (1.0, 0, 0, 0.5).

Topic 3: Textures

A bitmap is a fairly general term for a computerized image. The image can be use to decorate a surface (such as the face of a cube), and when it's so used, it is usually called a texture. Because English is friendly to verbing (making verbs from nouns), we call the process of applying a texture to a surface "texturing". Suppose the face of a cube you want to texture has a surface area that's exactly equal to that of your texture. Then, you just slap it on, and it fits. But what if the texture is too small? No problem, the software that handles the rendering (drawing of the 3D stuff) will generally automatically scale (stretch or shrink) the texture for you, to make it fit. Now, it's possible to override the scaling, but on SL avatars, you have less precise control of somethings, so you generally have to get your boundaries (seams) quite accurate on clothing, etc.

Topic 4: Your Avatar in 3Space (or 3D Space)

A texture is always applied to a flat surface, but many surfaces appear curved in SL. Is it magic? No, in fact, curved surfaces are made of many small adjacent flat surfaces, each at an angle to the next. Consider an equilateral triangle (3 equal length sides): is it round? Certainly not. Let's add a side; now we have square: it it round? Nope. Add another side, and now it's a pentagon. Round yet? Nope. Hexagon, septagon, octagon, and so on. Eventually, if we keep adding sides, we'll have a polygon with, say, 120 sides. At that point, if it were drawn on a normal-sized sheet of paper, you'd be hard-pressed to say whether it was really a polygon, or a circle, without looking too closely. At some point, each small piece becomes lost in the whole. Now consider the same idea in three dimensions. Your avatar is made up of many small flat patches, to each of which is applied part of the texture that makes up your clothing. So, it's possible to design a rectangular texture that somehow "molds" to your avatar in a nice way. But remember that some parts will stretch, because it's impossible to make all the patches the same size. So, keeping that in mind will help you design clothes that "fit" well.

Topic 5: Templates

There exist free templates to help you design the textures that will be used as clothing (or even skin) for your avatar. They will help you visualize the "seams" and boundaries where you can paint. I will probably edit this post later to add some links to these goodies, but if you are truly motivated, you will find them yourself (search the forums, use Google, etc).

Templates from LL:
https://secondlife.com/downloads/avatar.php

More template info:
/109/ec/22502/1.html

Topic 6: Editing Textures

To work on textures, you will need some sort of paint program. Adobe Photoshop (PS) is the de facto standard, and costs an arm and two legs. Fortunately, you will be left with an arm to work the mouse. Paint Shop Pro (PSP) is another option. The Gimp is a free program, and may be more suited to some budgets (like mine), though it is no slouch. Once you have selected a paint program, you can open up a template (see topic 5), and draw over top of it, or make more sophisticated edits. In most modern paint program, you will have the ability to work with multiple "layers". Imagine each as a transparency (you know, from overhead projectors) on which you can paint. The final image can be a composite of all these layers. You can switch individual layers on and off, fuse layers together, etc. Your final image will contain an alpha mask (probably the term), which shows what parts of the texture are transparent -- suppose you're making a sleeveless t-shirt: the areas where the sleeves belong would be transparent, so your av's arms would show. The specifics of this will be covered in a good reference book or tutorial that deals with the particular program you are using. If you have specific questions (more specific than "how do I use [such and such] program?", IM me or post them here. Be sure to supply details.

Topic 7: Extra Tools

There exist some programs that will let you "try on" your textures on an avatar outside the SL client. This provides two benefits: (1) you don't need to be online to work, (2) you don't have to spend 10L only to find out you botched the sleeves or something. (I will probably come back and edit this post to include links).

Paint directly on your av:
/109/f4/32414/1.html