Engine conventions

package.json

playcanvas

Coordinates and angles

• Use the right-handed coordinate system: +Y is up and the gameplay ground plane is XZ.
• Treat

  entity.forward

  and the camera viewing direction as -Z;

  entity.right

  is +X and

  entity.up

  is +Y.

  lookAt

  points -Z at the target.
• Expect glTF models authored toward +Z to need a yaw correction. Inspect and calibrate each directional model instead of applying one global correction.
• Pass degrees in XYZ order to high-level angle APIs.
• Keep pitch, yaw, and roll as application state. Do not repeatedly read

  getEulerAngles()

  and feed its decomposition back into

  setEulerAngles()

  .
• Interpolate periodic angles with

  math.lerpAngle()

  or rotations with

  Quat.slerp()

  , not scalar lerp across the 0/360 seam.

Transforms and units

• Use

  setPosition

  ,

  setRotation

  , and

  setEulerAngles

  for world transforms.
• Use the

  setLocal*

  variants below a parent.
• Treat units as metres. Physics gravity defaults to

  (0, -9.81, 0)

  .
• Keep gameplay transforms on a semantic root and asset-authoring corrections on a child.
• Do not scale rigid-body roots or skinned bones.

Cameras, materials, and bounds

• Perspective camera FOV is vertical and defaults to 45 degrees.
• Smooth an orbit camera's focus, yaw, pitch, and distance, then derive its position. Do not

  Vec3.lerp()

  between orbit positions on opposite sides of the focus; the chord crosses the subject.
• Before writing custom camera input, inspect the installed controller script and its matching Engine example. Preserve their gesture mapping and damping unless the product explicitly asks for different behavior; do not derive signs from memory.
• Define the input contract in screen space, then verify positive and negative movement on both axes with real input after a rendered frame. Judge the camera basis or a projected fixed landmark, not world-space camera coordinates or internal angle signs; both can approve inverted behavior.
• Materials cull back faces by default; counter-clockwise winding defines the front face.
• Clone a material before per-instance tinting or edits, and assign the clone; never mutate one shared by other instances, including default and asset-imported materials.
• Entities do not have an

  aabb

  . Union descendant

  meshInstance.aabb

  values after transforms have synchronized.
• Let

  Mesh.update()

  calculate local bounds. If passing

  false

  for

  updateBoundingBox

  , assign an explicit

  mesh.aabb

  before the mesh can be culled.
• Expand custom-mesh bounds by the maximum vertex-shader displacement; CPU bounds do not observe shader deformation.
• Treat offline skinned-mesh bounds as bind-pose estimates and confirm animated poses at runtime.

Imports

playcanvas

playcanvas/scripts/esm/**

Runtime confirmation

• Start the project's own dev server or build; do not construct a separate harness.
• Log the value from inside the Engine, using

  getPosition()

  ,

  getEulerAngles()

  , a

  meshInstance.aabb

  , or an anim component's active state, from a

  Script

  or an update callback.
• For large or vertex-displaced meshes, inspect their runtime AABB and

  visibleThisFrame

  after a rendered frame from at least two representative camera angles.
• Confirm a directional model's visible front aligns with its semantic root's

  forward

  ; a stored yaw or runtime transform alone cannot prove mesh facing.
• Read that logged value from the browser console. Screenshots judge composition and orientation; numeric claims require logged values.
• Record the confirmed value in application state or an asset tuning record, then remove the logging.