# Scenes and prefabs

> Draw stadiums with discs, walls, lines and joints; reuse groups of objects as prefabs; give each player a body.

## Scenes

A scene is a place a match can happen in. Open one from the Project panel.

![The scene toolbar: select, pan, disc, visual, wall, line, joint, instance, the grid, mirroring and zoom.](/shots/scene-tools.png)

| Tool     | Key | Makes                                                                  |
| -------- | --- | ---------------------------------------------------------------------- |
| Select   | V   | Selects and moves. Drag on empty space to box-select                   |
| Disc     | D   | A disc where you click                                                 |
| Visual   | S   | A visual of the shape picked from its arrow menu (below)               |
| Wall     | W   | A wall, one click per point. Click the first to close it; Escape stops |
| Line     | L   | A line that notices discs crossing it                                  |
| Joint    | J   | A link between two discs                                               |
| Instance | I   | A copy of a prefab                                                     |

Moving around:

- **Space** + drag pans, the **mouse wheel** zooms, **F** frames the selection.
- **Arrow keys** nudge what you selected.
- Drag a selected wall's square handles to move its **points**, and the dot
  in the middle of an edge to **curve** it. **Alt**-click a dot to add a
  point there, or a square to remove it.
- A selected visual has handles too: a line's or polygon's **points**, a
  box's or image's **corners** (the opposite corner stays put), a circle's
  or arc's **radius**, and an arc's two **ends**.
- The ring above a selected visual, disc or wall **rotates** it, in steps
  of 15°; hold **Alt** to turn it freely.
- Hover a tool to see what it does and its key.

What players see of each object is its **Look** in the inspector: a disc's
fill, outline, avatar, layer and spin; a wall's line colour and width. Lines
and joints have no look; Play's physics view shows them.

**Known by** in the inspector hides a disc or wall from some players. It is
an audience built from blocks: **Everyone**, **Players** (any list, such as
a team), **Players with a role**, **Players near** it (seeing through no wall
of chosen groups), **Any of** several, and **All but** some players. It
follows what it reads: when a team changes, so does who knows the disc.
Players outside never receive it; see [Who sees what](/games/audiences).

## Visuals

A visual draws something players see: a circle, box, polygon, line, arc,
text, image, or a group of visuals that move, turn and fade together.

Pick the shape from the arrow beside the **Visual** tool; the tool keeps it
for the next one. The shape shows where it will go before you click.

- **Circle**, **text**, **image**: click where it goes. Drag out a circle
  to set its radius.
- **Box**, **line**: drag from one point to the other, or click both. Hold
  Shift for a square box, or a line at a multiple of 45°.
- **Arc**: drag from its center; the drag sets its radius and where it
  starts. Drag its ends round the circle afterwards.
- **Polygon**: click each corner, then the first one to close it (or press
  Escape, or right-click, once it has three).

Lines and arcs start as white outlines; the other shapes start filled
white. An image shows the picture chosen in its **Image** field, uploaded under
[Assets](/studio/assets).

A **group** holds other visuals and draws them in its own frame: moving,
turning, scaling or fading the group does the same to all of them, as for a
score badge made of a box and a text. To make one, select the visuals,
right-click and choose **Group**; **Ungroup** takes them out again. In the
Scene tree, drag a visual onto a group to put it inside, or out of it to
take it out; it stays where it is. A group left empty shows a small dashed
square, so it can still be picked.

A click on the canvas picks the whole group. **Double-click** it to pick the
visual under the pointer inside; while one of its visuals is selected,
clicks pick its other visuals, and they move, resize and turn like any
other.

The inspector changes a placed visual's shape at any time.

- **Where**: on a body (it follows it, with an offset) or at a point.
- **Shape** and its sizes; a polygon's or line's points are dragged on the
  canvas.
- **Fill**, **Outline**, outline width, rotation, scale, opacity, layer,
  and **Shown to**, an audience like **Known by**. **Players near** works
  on a visual on a body, or at a point the game knows; one placed by what
  screens work out, such as a disc's position, must go on the body
  instead. To fade it in, set **Opacity** to **Fade by distance**.
- A ring is a circle with an outline and no fill: give its radius as the
  body's radius plus a gap, such as `Ball.radius + 4`.

Every value is a **binding**: a description that always holds. What every
screen can work out by itself, such as a disc's position, speed or height,
is drawn every frame at no cost to the game; what only the game knows, such
as a variable or a name, is sent again whenever it changes. You never
choose between live and set once.

**Leaves the ground** lets a disc fly: its height, rising speed, fall
gravity and landing bounce. **Tall** (under Collision) sets how tall a disc
or wall stands; objects only touch where their heights overlap. During
play, rows use _Launch {disc} upward at {speed}_, _Set {object}'s tall to
{value}_ and the trigger _{disc} lands_; _Create a disc_ and _Create a wall_
take the same settings. See [Height](/games/world-and-physics#height).

Settings → **Starting scene** picks where matches start.

## Prefabs

A prefab is a group of objects you can reuse, like a player or a goal.

1. Press **New prefab** in the Project panel and draw in it.
2. Place copies in scenes with the **Instance** tool.
3. Change a copy in the Inspector; **reset** brings back the prefab's value.

## One body per player

![A Player prefab's Inspector with One per player turned on, where it spawns, its controls, acceleration and damping.](/shots/prefab-player.png)

Turn on **One per player** and every player gets their own copy:

- **Spawn at**: where it appears, such as `SpawnPoint(player)`.
- **Controls**: the keys it uses (see [Controls](/studio/controls-and-roles)).
- **Acceleration** and **Damping**: how it moves.

Rows can then use the player's `disc`, for example in _A player enters the match_.