light_beam¶

type: "light_beam"

A glowing shaft of soft light emitted from each position along a direction (straight up by default). top_scale flares the top: 1 = cylinder, 2 = cone with twice the top radius. softness increases the number of concentric shells and fades their alpha: 0 = two hard tubes, higher = many thin, faint shells (a smooth blurred column).

Fields¶

Every world overlay also accepts positions (static or entity-anchored), region or the pos_x/pos_y/pos_z params, plus the shared definition fields (duration, easing, loop, persistent, fade_ticks, sound).

Field	Type	Default	Meaning
`radius`	float	1.5	Beam radius in blocks (≥ 0.1, no upper limit)
`height`	float	48	Column length along the direction, from the anchor (≥ 1, no upper limit)
`dir_x` / `dir_y` / `dir_z`	float	0 / 1 / 0	Beam direction, normalised (the default points straight up). A zero vector falls back to up
`end_at_x` / `end_at_y` / `end_at_z`	float	unset	A world point the far end of the beam must land on. When set, the anchor is derived (`end − axis × height`), so the beam finishes exactly there and `positions` is ignored
`top_scale`	float	1	Top radius multiplier (≥ 0.1, no upper limit): 1 = cylinder, >1 = flared cone
`softness`	float	0.6	More concentric shells with lower alpha (0 = crisp, 2..4 = soft blurry column)
`top_fade`	float	0.4	Alpha at the top relative to the base (0..1)
`bottom_fade`	float	0	Alpha at the bottom relative to the base (0..1)
`red/green/blue`	float	1 / 0.95 / 0.75	Beam colour
`through_blocks`	float	0	1 = visible through walls
`intensity`	float	1 (fades to 0)	Beam opacity

Example¶

The direction is an ordinary animatable param, so it can be keyframed, driven by an expression or bound. Binding it to the camera look aims the beam wherever the viewer is looking:

"params": {
    "dir_x": { "bind": "look_x" },
    "dir_y": { "bind": "look_y" },
    "dir_z": { "bind": "look_z" }
}

{
    "type": "light_beam",
    "duration": 60,
    "params": { "radius": 1.5, "height": 48, "top_scale": 1, "softness": 0.6, "top_fade": 0.4, "bottom_fade": 0 }
}

A beam that ends on a chosen point. end_at_x/end_at_y/end_at_z name the world point the far end of the beam must land on. The anchor is derived from it (end − axis × height), so the geometry finishes exactly at the point. With the default axis the beam hangs straight down from height blocks above it — a beam falling out of the sky onto the spot:

{
    "type": "light_beam",
    "duration": 80,
    "params": {
        "dir_y": -1.0,
        "height": 60.0,
        "radius": 1.0,
        "end_at_x": 120.5,
        "end_at_y": 64.0,
        "end_at_z": -340.25
    }
}

They are ordinary animatable params, so the landing point can be keyframed, driven by an expression or bound. To run a beam from A to B, set end_at_* to B and give the axis and length between the two points (dir_* = normalize(B − A), height = |B − A|) — positions is not used in that form. Mind the sign: the beam travels toward end_at, so a beam coming down from the sky has dir_y = -1.

/vfx playat vfxweaver:light_beam 8 70 8 {[radius:2],[top_scale:2],[softness:3]}

Code¶

/vfx play vfx_demos:show_light_beam

Its datapack definition:

{
    "type": "light_beam",
    "duration": 160,
    "easing": "ease_in_out_cubic",
    "persistent": true,
    "loop": true,
    "fade_ticks": 12,
    "positions": [
        [
            1996,
            100,
            1996
        ]
    ],
    "params": {
        "red": 1.0,
        "green": 0.95,
        "blue": 0.75,
        "radius": {
            "keyframes": [
                {
                    "time": 0,
                    "value": 1.0
                },
                {
                    "time": 80,
                    "value": 1.8
                },
                {
                    "time": 160,
                    "value": 1.0
                }
            ]
        },
        "height": 16.0,
        "softness": 1.2,
        "top_scale": 1.5,
        "top_fade": 0.5,
        "bottom_fade": 0.0,
        "through_blocks": 0.0,
        "intensity": {
            "keyframes": [
                {
                    "time": 0,
                    "value": 0.25
                },
                {
                    "time": 80,
                    "value": 0.9
                },
                {
                    "time": 160,
                    "value": 0.25
                }
            ]
        }
    }
}

Variants¶

`show_light_beam_dir`¶

/vfx play vfx_demos:show_light_beam_dir

A beam at an arbitrary angle: dir_x/dir_y/dir_z are the axis and height the length along it. The cone shell is emitted around that axis, with the vertical basis pinned so a tilted beam never rolls as it animates.

{
    "type": "light_beam",
    "duration": 200, "easing": "ease_in_out_cubic", "persistent": true, "loop": true, "fade_ticks": 12,
    "positions": [ [1996, 100, 1996] ],
    "params": {
        "red": 1.0, "green": 0.95, "blue": 0.75,
        "radius": { "keyframes": [ { "time": 0, "value": 1.0 }, { "time": 100, "value": 1.6 }, { "time": 200, "value": 1.0 } ] },
        "height": 18.0, "softness": 1.2, "top_scale": 1.5, "top_fade": 0.5, "bottom_fade": 0.0, "through_blocks": 0.0,
        "dir_x": { "keyframes": [ { "time": 0, "value": 0.6 }, { "time": 100, "value": -0.6 }, { "time": 200, "value": 0.6 } ] },
        "dir_y": 1.0, "dir_z": 0.0,
        "intensity": { "keyframes": [ { "time": 0, "value": 0.3 }, { "time": 100, "value": 0.95 }, { "time": 200, "value": 0.3 } ] }
    }
}

`show_light_beam_end_at`¶

/vfx play vfx_demos:show_light_beam_end_at

The other form: end_at_* names the point the beam ends at, so the axis and length follow from the position and the direction — no height to keep in sync. Mind the sign, the beam travels toward end_at, hence dir_y = -1 for a beam coming down from the sky.

{
    "type": "light_beam",
    "duration": 200, "easing": "ease_in_out_cubic", "persistent": true, "loop": true, "fade_ticks": 12,
    "params": {
        "red": 1.0, "green": 0.95, "blue": 0.7,
        "radius": 0.7, "height": 60.0, "softness": 0.8, "top_scale": 1.0, "top_fade": 0.2,
        "bottom_fade": 0.0, "through_blocks": 0.0,
        "dir_y": -1.0, "end_at_x": 2004.0, "end_at_y": 100.0, "end_at_z": 1996.0,
        "intensity": { "keyframes": [ { "time": 0, "value": 0.3 }, { "time": 100, "value": 1.0 }, { "time": 200, "value": 0.3 } ] }
    }
}