From BlenderWiki

Animating Lamps

Here we are not going to talk about moving lamps, rotating them, etc. – this is nothing more than object animation! Let’s just remember you about constraints, especially tracking ones, which might be very useful to track a character with a spot, for example…

We will rather see what lamp specific properties you can animate. All the relevant Ipo curves are gathered in the Lamp set of the Ipo Curve Editor window.

Note that lamps can, as well as materials, use textures – and you can animate how these textures are mapped to their lamps (e.g. to simulate « gobos » [is this english?] in a discotheque… or complex shadows, like tree leaves cast on the ground, when you have no time to use raytraced shadows). However, as this is nothing more than a sub-set of the material’s possibilities, we won’t detail this topic here – read the material animation page, later on. And obviously, you should have already read the lighting chapter!

Options

Apart from the texture mapping curves (Ofs…, Size…, Tex…, DefVar and Col), you can animate:

Energ

This curve controls the Energy of the lamp, i.e. how much light it produces (value ranges in [0.0, 10.0])! A nice way to simulate e.g. the flickering light of a candle, or lightnings in the night…

R, G, B

These curves control the base color of the lamp (values range in [0.0, 1.0]). You might use them e.g. to make your light slightly blueish when clouds go past the sun…

Dist

This curve controls the Dist factor of lamps having a falloff of their light intensity (namely Lamp, Area and Spot – value ranges in ]0.0, 5000.0]). Animating this setting will create a strange effect, as it changes how light decays with the distance from it source… It might perhaps be useful to simulate an atmosphere with varying opacity (e.g. some smog, smoke or dust progressively disappearing…).

SpotSi and SpotBl

These two curves are specific to Spot lamps (i.e. are only effective with these), as they control the angle of the spot, and the softness of its borders (values range in [1.0, 180.0] for SpotSi, and [0.0, 1.0] for SpotBl.

Quad1 and Quad2

These curves only concern the Lamp and Spot lamps which use the Lin/Quad Weighted falloff type (values range in [0.0, 1.0]). They use the old name of the two Linear (Quad1) and Quad (Quad2) sliders, which respectively represents the influence of linear and quadratic falloff… Quite specific stuff, very seldom useful, I think.

HaInt

This curve control the halo intensity (HaloInt slider) of the Spot lamps that have one (value ranges in [0.0, 5.0]).

Example

Let’s illustrate this with a flying torch deep in a cave.

We won’t detail the cave and torch creation – the first one is an deformed icosphere with Subsurf and Displace modifiers, and the second one, a cylinder scaled and subdivided several times in its length, with a particle system to materialize its fire.

The torch will be the only light source of the scene. Add four Lamp lamps, all using the same lamp datablock (once added, in the Link and Materials panel of the Editing context (F9), select the same datablock for the LA field). Place them around the tip of the torch, and parent them to it (with e.g. a Child Of constraint). Give them an orange color (e.g. (1.0, 0.8, 0.4)), a short half-intensity Distance (2.0, but this depends on the size of your cave!), and an Inverse Square falloff. Also let them cast ray shadows (soft shadows, if you have enough computing power…).

Now, open an Ipo window, select the Lamp type, and create an Energ curve. You can for example start at zero (no energy, the scene is whole black), give a short and intense flash (10 over a few frames) to simulate a sort of lightning lighting the fire, then back to very low (0.25), and then a gently varying curve over the rest of the scene, to simulate the irregularities of the flames.

You might also copy/paste the same curve (except for the first “flash” control points) to the E_Freq torch’s Ipo curve (in the Particles set), to synchronize the quantity of particles with the luminosity of the lamps.

Once your torch is flying, you should get something as shown below – you can download the blend file File:ManAnimationTechsLampExFlyingTorch.blend.