World Units and Image Scale

A character moving at 3 meters per second covers three world meters in one second. Its image can be large or small. The world’s measurements stay the same.

Myth uses meters for world distances in both 2D and 3D. World velocity uses meters per second. Images and screen-space interface content use pixels.

Pixels per Unit

Pixels Per Unit, or PPU, describes how many image pixels span one world meter. The project default is 32 pixels per meter.

Find it under Game Settings > General > World Scale > Pixels per Meter. That’s the project’s PPU. General Settings explains its range and reset behavior.

At PPU 32, a 64-pixel image width has a natural width of two world meters. A Sprite or Tileset can have its own image density. When it has none, the project density applies.

At 32 Pixels per Meter	World Relationship
A 32-pixel image width	1 meter at that image density
A 64-pixel image width	2 meters at that image density
A speed of 3 meters per second	96 pixels of equivalent motion per second

These calculations describe an image’s natural world size; Object scale and camera framing determine its final screen size. Check the authored world size separately from the art file’s resolution.

Choose a World Size

Begin with one character at a useful world size and a slow movement speed. Look at it in Game View. Then choose the remaining level dimensions.

For an Object presented in the 2D world, check the Sprite’s size in meters and the Object’s separate scale. At PPU 32, a 2 meter Sprite has a 64-pixel equivalent extent before camera scaling. Confirm its size in Game View and a fresh playtest.

A world velocity of 100 means 100 meters per second, which can cross a small game view almost immediately. Try 3 meters per second first.

Changing project PPU affects rendering and image scale without multiplying world speeds or gravity. See Display and Rendering for window and logical-resolution controls.

Read the Field’s Unit

A Window / UI Object uses pixel measurements for its own presentation. A world Object uses world measurements. Read the field label before copying a number between them.

Field or Quantity	Unit	Example
World Position or world component size	Meters	Size 2 describes two meters.
World velocity	Meters per second	Velocity 3 requests three meters per second.
Object Scale	Dimensionless multiplier	Scale 2 doubles the applicable authored size.
Screen Offset and screen-space bounds	Pixels	A 160-pixel UI width is not 160 meters.
Sprite source, Margin, and Spacing	Source-image pixels	A 64-pixel source with a 2 by 2 grid has 32-pixel cells when borders and gaps are zero.
Angle and rotation	Degrees unless the field states otherwise	A 90-degree 2D direction points up.
Alarm and recurring timer interval	Seconds	1 is a one-second simulation delay.
Particle Emit every (ms)	Milliseconds	100 corresponds to ten emission intervals per second.

The world edit grain is 0.001 meter, or one millimeter. Screen offsets remain pixel values. Coordinates and Presentation shows the native controls for both spaces.

Older Projects

Current projects use project format 2. The loader upgrades supported format-1 projects when you open them. Earlier interface-position Actions keep their behavior through that upgrade: their old World choice becomes Screen where it referred to the interface Object’s own pixel frame.

Older meter-based projects without a format field can open when they carry all four meter stamps: units2d, logicUnits, units3d, and units3dShared. Their supported data upgrades on load too. The loader also converts the remaining older platformer-grid and creature-speed fields.

Pixel-era projects are not supported by the current loader. Keep your original file intact. Adding format numbers or meter stamps by hand does not convert its data.