Archive for May, 2009

Tutorial 3: More Options

Saturday, May 16th, 2009

One underused area of the texture dialog is the ‘Bumpiness’ dropdown. This adds ‘depth’ details to your texture. The effect on an existing texture is often subtle, but can be useful to add a touch of additional realism.

Here’s an example. The box on the right has the Darkness bumpmap applied to it:

Bumpmap example

Bumpmap example

However, you can use bumps on a face which doesn’t have any texture applied to it. This can give useful effects which will display more quickly, because there is no texture to be downloaded from the server.

Here’s an example using the woodgrain bumpmap (with some colouring applied):

Woodgrain example

Woodgrain example

For an even better effect, add some shininess — you will find this in the dropdown below the ‘Color’ box. It adds varying degrees of reflectiveness to the texture.

Combining colour, bumpmaps, and shininess can create interesting results without the need to have an actual texture file. For instance, the following speaker box uses no texture files at all:

Speakerbox example

Speakerbox example

Finally, let’s take a quick look at the group of three options at the top-right of the Texture tab: Transparency, Glow, and Full-Bright.

Transparency, glow, and full-bright in the Build dialog

Transparency, glow, and full-bright in the Build dialog

Transparency is fairly obvious — the higher this value, the more transparent the object is. This is not the only way to make a prim (or a prim face) transparent (it can also be done using a texture), but it is the simplest.

One unexpected result (if you are new to building things in Second Life, and if you are new to 3D graphics), is what happens if you make a single face transparent. Do you get to see the inside of the object? Well, no. Second Life doesn’t actually draw the inside of prims, so if you make a face transparent, you will see right through the prim.

Moving on to Glow, this was introduced a relatively short time ago, and probably counts as one of the most abused graphic features in Second Life. Part of the problem lies in the fact that different graphic cards seem to render glow differently, so that what looks like a perfectly acceptable glow on one computer might appear like a blazing sun on another.

With that in mind, the sensible thing is to keep glow values low. Beware of anything higher than about 0.2. For most effects, values as low as 0.01 or 0.02 often give the best results.

Combining glow and transparency can yield some very nice ‘light’ effects:

Light example

Light example

Finally, Full-Bright. It might not be immediately obvious what this does, especially if you apply it during Second Life ‘daytime’. Simply, this will ignore the effect of Second Life lighting (sun, moon, or local lights), and will always display the texture at it’s actual colour values. Full-bright objects look as if they are illuminated at night, so this is a useful option for lights.

Let’s apply this to our ‘light’ from the previous example. Here’s a version without full-bright, and then with:

Full-bright example

Full-bright example

That concludes this initial series of tutorials on textures. I haven’t covered all the features on the texture tab, and there are still lots of other things to find out about textures, but if you are new to building objects in Second Life this should have given you enough to start with.

Tutorial 2: Repeat, Offset

Friday, May 8th, 2009

In the previous tutorial I gave you a guide to getting textures on to your prims. In this tutorial, I’ll show you how to change the appearance of the applied textures.

Let’s start with the simplest, but most frequently-used options — the Repeat options. These allow you to set how many times the texture will repeat across each face (or the selected face) of the prim.

Here are two boxes with the same texture, the first one with both repeats set to 1, and the second to 3 each. The most common use for this is where you have a simple, small texture which you want to use to cover a large area.

Simple Repeat Example

Simple Repeat Example

What happens when you resize the prim that the texture is on? The answer depends on whether you have the ‘stretch textures’ box ticked or not. If you tick this box, and then resize the prim, this is the result:

Stretch Example

Stretch Example

If the ‘stretch textures’ box is unticked, you get the following:

No-Stretch Example

No-Stretch Example

This might seem a surprising result. It is because textures are centered on the prim face, rather than being anchored to the top-left. However, this leads very neatly on to the next feature — Offset.

The texture offset fields are near the bottom of the build dialog. The offset amount is a fraction of the size of the texture, so an offset of 1.00 will have not effect — the texture is moved by it’s complete width or height.

Because textures are centered on prim faces, offsets should be thought of as offsets from the middle. In our example above, we want to shift the texture by half it’s height, to align it to the top of the prim, like so:

Simple Offset Example

Simple Offset Example

There is another way of setting the repeat for textures, which works in a slightly different way, and can sometimes be very useful. This is the ‘repeats per meter’ setting.

To show the effect, let’s have an example:

This archway looks fine from the front, but the texture on the sides is wrong. This is because the texture is set to repeat 1 x 1 horizontally and vertically. The sides of the arch are narrower, so the texture gets ‘squashed’. Now, it would be possible to fix this by changing the repeats on the side (by selecting the side texture only — see the previous tutorial to find out about ‘select texture’).

Squashed Texture Example

Squashed Texture Example

However, there is an easier way, using ‘repeats per meter’. Setting this to 1.0 (in this case), and then clicking the ‘Apply’ button will size the texture so that it repeats every 1.0 meters. Because the prim in this case is 1m x 0.5m, the front and back will remain unchanged, but the texture on the sides will now display correctly:

Repeats Per Meter Example

Repeats Per Meter Example

Ok, I think that will do for this tutorial. Happy texturing!