Posts Tagged ‘full-bright’

Second Life Prim Lights – 3

Saturday, July 10th, 2010

Full-bright and Glow

This is the last article in my short (and rather infrequent) series about lights in Second Life. I’m going to take a look at two elements of textures which are often used in conjunction with lights, and which are also widely misunderstood and misused.

Let’s start with Full-bright. This can be switched on or off on the Texture tab of the Build dialog, and applies to the currently selected texture, or to all the textures on the currently selected object if you haven’t selected an  individual face.

What does it actually do? The most obvious effect is that during SL ‘night’ the texture will appear bright (as the name of the option suggests). During daylight the effect is, predictably, less obvious. In fact, sometimes the object might actually appear to be darker in daylight.

Here is the same scene in both day and night. The picture on the wall has full-bright set on it, and you can probably see that the picture is displayed identically in both light settings.

Full-bright example

Let’s step back a moment. How does Second Life create the ‘night-time’ effect? Well, apart from changing the sky, it obviously makes all the objects in the world darker. It does this by taking the colour which they should be, and blending it with the ‘nighttime’ colours.

What might be less obvious, is that it does something similar during daylight. It takes the colours, and adjusts them according to the current lighting. This is how you get the distinctive orange lighting effect at sunset that some people  complained about when Windlight was first released.

When you set a texture to full-bright, this blending is switched off for that texture, so it always displayed at it’s actual colour, regardless of the current lighting. At night, this has the effect of making the object seem to light up — in fact, it is simply not being darkened.

So much for full-bright. Now what about its companion, Glow? Unlike full-bright, this is exactly what it says. When you set a glow value for an object, it acquires a glowing halo around it. This can range from a subtle, barely visible aura, up to a near-blinding glare.

Glow example

Transparency tends to lessen the effect of glow slightly (the lower row in the picture has transparency applied).

Under most circumstances, using low values is best, usually no more than about 0.25, and often less than that.

One thing to be aware of is that if two glowing objects overlap in the viewer, the glow effect is doubled. This is not always what you want to happen, so you probably need to be careful if you place glowing objects close together.

Overlapped glow example

Another unfortunate effect that I’ve often seen is where the glow is being used with an object which has a partially-transparent texture. For the glow to show up in this case it needs to be set quite high. When the texture is fully loaded, the effect is subtle and often beautiful. Unfortunately, while the texture is still being loaded, the glow is in full force, and often overwhelmingly bright. There is not much that can be done about this, but if you intend to use this kind of effect, you should be aware of this pitfall.

Partially-rezzed glow example

Glow and full-bright work very effectively together when creating a light. As a simple example, rez a prim, set its transparency to 25 (if you set it too high you will lose some of the effect), then switch full-bright on and set the glow to 0.2. The result will, of course, not actually illumine the surroundings unless you set the Light feature on, but this kind of ‘fake light’ can give the illusion of there being more lights than SL actually supports, especially if you use several of these in conjunction with a single ‘real’ light.

Full-bright and glow lighting example

Some SL photographers make use of a interesting effect which happens when an avatar stands in front of a ‘glowing’ texture. This is easier to show than to describe, although the effect is quite subtle, and is caused by the glow slightly spilling over the edges of anything in front of it. Here are ‘without’ and ‘with’ glow versions (this is a rather exaggerated version, with the glow set quite high to make the effect obvious):

Photo-glow effect

However, if you intend to save your photos, there is an issue to be aware of, which is that the Second Life snapshots tend not to capture glow correctly. For example, the scene of streetlights on a wall (above) was captured using my computer’s screen-capture, rather than the Second Life screenshot, which looked like this:

Glow snapshot problem

Finally, ‘glow’ works best when it is used for subtle effect, and with some restraint. Whatever you do with ‘glow’, please don’t do this:

Glow abuse example

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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.

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