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Moriash Moreau: My Second Life
Thursday, November 03, 2005
SL Webcomic Tips, Part 2
Welcome back to Webcomic Tips. Here's the previous installment, if you missed it. Today, I'm going to talk about lighting. Don't worry, we'll move on to some more useful tips in the next installment, once I get the basics out of the way.

Proper lighting will usually mean controlling the sun. (Stop and think about that. "It's too dark!" "Eh, just move the sun.") In order to do this, you will need to use some of the Debug menu functions. (If you don't already have it enabled, hit CTRL-ALT-D to reveal it. Be careful tinkering with this, as some of the functions routinely crash your client.) You've probably already tinkered with the daylight control functions, but I'll go ahead and explain them, just in case. Take a look at the World menu under the Debug pulldown. There will be two options that we're concerned with: Force Sunset and Mouse Moves Sun. (The third option, Sim Sun Override, is only usable if you're the owner of an Island sim. It can be used to set the sun position for everyone in the sim.)

Force Sunset will simply convert night to day (perhaps it should have been named "Force Sunrise"). Select it from the Debug menu (or just hit CTRL-SHIFT-N), and the sun will shortly appear and hang motionless in the sky (you'll have to relog to set it back in motion). Note that this function (and Mouse Moves Sun, described below) will only work on your client. Everyone else will see the Sun moving as normal, and any scripts that use llGetSunDirection to track it will be unaffected. This is also a handy tool if you're in the middle of build when the Sun goes down.

Force Sunset will sometimes be all that you need. But, more often, you'll want more specific control of where and how the light falls. In order to do this, you'll need to use the Mouse Moves Sun feature. I've found that it's much easier to use the shortcut (CTRL-ALT-M) for this function. In order to set the sun in the desired location, do the following:
  1. Enter Mouselook.
  2. Hit CTRL-ALT-M. The sun should shortly appear on top of your Mouselook crosshairs.
  3. Using your mouse, move the sun to the desired location (you don't need to click or drag, just move the mouse).
  4. Hit CTRL-ALT-M again to turn off the Mouse Moves Sun function.
You can also turn the function on from the Debug menu pulldown (turn it on, enter mouselook, move the sun, leave mouselook, and turn it off). But I've found the shortcut keys are usually more convenient.

In most cases, you'll want the sun either directly above, or above and behind the camera. You'll probably want to tinker with it a bit for the best effect. There is no limit to the sun placement. So if, for example, your characters are watching a sunset from the balcony, but the balcony faces South, you can simply drag the Sun to the southern horizon. The client will automatically adjust the color and appearance of the Sun (and its light) depending on its distance above the horizon, so you can create an instant sunset wherever you need it.

If you want to film at night, simply drag the Sun below ground. The Moon appears opposite from the Sun, so it will automatically appear when the Sun drops below the horizon. (Yes, the Sun and the Moon orbit the world in Second Life.) Thus, you can make a dramatic full moon (and that's it- no crescent moons) when necessary. Unfortunately, you can't grab the moon using Mouse Moves Sun. You can only manipulate the Sun, and control the Moon's location second-hand.

Unlike with Force Sunset, the Sun will continue to move from East to West after being placed with Mouse Moves Sun. It will not, however, move North or South. It will just keep moving westward from wherever it was placed. This is important when you're setting up a series of complex shots intended to only be moments apart. It's a dead giveaway when it's apparent sunrise in frame one, and nearing SL noon (only 90 minutes later) by frame four. Always remember to check the Sun's placement before shooting each frame.

IF you need a dramatically clear sky (such as when you want a clear view of the stars), you can also turn the clouds on and off using the Debug menu. In the pulldown, select Rendering, Types, Clouds to turn cloud rendering off. You can also turn off Trees and other obstructions, if necessary. All of the options under the Rendering, Types Debug submenu are safe, if you want to play with them. Surface Patch (that is, the ground) is handy for when you lose prims by accidentally setting your Z coordinates too low.

Locally lit objects can also be used for some effects, such as washing an area with a color. This is what we did here. We used two large prims, set to red and blue (or yellow and pink), and set them directly in front of the objects we wanted to photograph. We actually made the prims 100% transparent (use a script and the llSetAlpha command, or simply using the "alpha" texture from the library), so that we could film from behind them. The objects will still give off light, even though they are invisible.

So we've discussed making the scene brighter, but how about darker? This is considerably more difficult, especially with avatars. Maddeningly, you can place an avatar in a completely black room at the bottom of a well, and he'll still show up as if in full daylight. There are two ways to address this. One, you can film the scene in full daylight, then use the brightness controls in your favorite art package after the fact. If you plan on doing this, make sure and light the scene as if it were daylight. Otherwise, the internally lit avatars will remain bright even after the background objects are too dark to see.

The second method is simply to put a dark, semi-transparent prim between the camera and the subject. Take a big, flat prim, make it blank, color it black, and adjust the transparency to taste. You'll effectively be placing a pane of dark glass in front of your camera. This is the SL equivalent of a time honored method of filming night time scenes in old B movies. It's not perfect (be sure and get the moon up in the background, if it's to be visible), but it's a fairly close approximation.

I originally came up with this idea for use in a live-action, in-world play. Sadly, the project died of internal Drama before the first rehearsal. (Is that irony? Alanis Morissette ruined my understanding of the term, so I can't say for certain.) The stage was to have a large, thin pane along the front edge, designed to simulate darkness when needed by partially obscuring the view from the audience. Oh well, maybe someone can use the technique someday.

Well, that's about all I have to say about lighting. Next up: actor wrangling!
Much of the advice regarding light sources is obsolete now that full local lighting has been enabled. Take a look at this video by Torley Linden for tips on creating dramatic local lighting effects.
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