Object

An Object is the most basic thing that can be added to the game 3D scene.

It has a position, a rotation and a scale and can contain child Objects, including Object extensions like Shape.

An object by itself does not render anything on screen, but it can contain Shapes and thus become a parent coordinate system for them.

An Object can also take part in the physics simulation when setting Object.Physics to true.

Constructors

Object ( )

Creates an Object.

local o = Object()
World:AddChild(o) -- adds o to the [World] (top level object in the game scene)

Functions

nil AddChild ( Object child, boolean keepWorld optional )

Adds given Object as a child. Object extensions like Shape or MutableShape are naturally accepted too.

The keepWorld optional parameter, false by default, dictates whether to maintain the child's world or local position and rotation. Keeping world will ensure the object doesn't move in the scene, adjusting its local position/rotation accordingly; keeping local will have the object move in the scene in order to maintain an equivalent local position/rotation relative to its new parent.

local o = Object()
local myShape = Shape(Items.someuser.someitem)
o:AddChild(myShape)
nil ApplyForce ( Object self, Number3 value )

Apply a force to Object, taking into account its Mass.

Returns true if the two Objects may collide with each other.

nil GetChild ( integer index )

Get child Object at index.

if o.ChildrenCount > 0 then
  print(o:GetChild(1)) -- prints first child
end

Get Object's parent.

print(myObject:GetParent())
nil Load ( string itemName, function callback, table config optional )

Loads the given item asynchronously and calls the callback once done. The parameter itemName follows the usual naming convention user.item.

This is a function of the global Object, to be called as Object:Load(itemName, callback, config).

The config table options are as follows,
- mutable allows to create the item shapes as MutableShape instead of Shape. Default false.
- bakedLight allows to generate baked lighting for the item shapes. Default false.

Converts a local position to world coordinate system.

local p = Number3(1, 2, 3)
local pInWorldCoords = myObject:PositionLocalToWorld(p)

Converts a world position to local coordinate system.

local p = Number3(1, 2, 3)
local pInLocalCoords = myObject:PositionWorldToLocal(p)
nil RemoveChild ( Object child, boolean keepWorld optional )

Unsets parent/child relationship with child parameter. The child ends up being deleted if it has no other references.

The keepWorld optional parameter, false by default, dictates whether to maintain the child's world or local position and rotation. Keeping world will ensure the object doesn't move in the scene, adjusting its local position/rotation accordingly; keeping local will have the object move in the scene in order to maintain an equivalent local position/rotation relative to its new parent.

o:RemoveChild(someChildObject)
nil RemoveChildren ( boolean keepWorld optional )

Unsets parent/child relationship with all children. Individual children end up being deleted if they have no other references.

The keepWorld optional parameter, false by default, dictates whether to maintain the child's world or local position and rotation. Keeping world will ensure the object doesn't move in the scene, adjusting its local position/rotation accordingly; keeping local will have the object move in the scene in order to maintain an equivalent local position/rotation relative to its new parent.

o:RemoveChildren()
nil RemoveFromParent ( boolean keepWorld optional )

Removes the Object from its parent. Doesn't do anything if the Object has no parent.

The keepWorld optional parameter, false by default, dictates whether to maintain the child's world or local position and rotation. Keeping world will ensure the object doesn't move in the scene, adjusting its local position/rotation accordingly; keeping local will have the object move in the scene in order to maintain an equivalent local position/rotation relative to its new parent.

o:RemoveFromParent()

Resets to Object's original collision box. For example, Player and Shape objects will revert to fitting their model bounding box.

nil RotateLocal ( Number3 eulerAnglesXYZ )
nil RotateLocal ( number eulerAngleX, number eulerAngleY, number eulerAngleZ )
nil RotateLocal ( Rotation rotation )
nil RotateLocal ( Number3 axis, number angle )

Rotates the Object in its own coordinates system.

o = Object()
-- rotate with provided Euler angle
o:RotateLocal({0, 0, math.pi / 2.0})

-- rotate along specified axis
o:RotateLocal(o.Forward, math.pi / 2.0)
nil RotateWorld ( Number3 eulerAnglesXYZ )
nil RotateWorld ( number eulerAngleX, number eulerAngleY, number eulerAngleZ )
nil RotateWorld ( Rotation rotation )
nil RotateWorld ( Number3 axis, number angle )

Rotate the Object in the World coordinates system.

o = Object()
-- rotate with provided Euler angles
o:RotateWorld({0, 0, math.pi / 2.0})

-- rotate along specified axis
o:RotateWorld(o.Forward, math.pi / 2.0)
-- same as o:RotateLocal({0, 0, 1}, math.pi / 2.0)
Rotation RotationLocalToWorld ( number eulerAngleX, number eulerAngleY, number eulerAngleZ )

Converts a rotation from local to world relative to this object.

Rotation RotationWorldToLocal ( number eulerAngleX, number eulerAngleY, number eulerAngleZ )

Converts a rotation from world to local relative to this object.

nil SetParent ( Object parent, boolean keepWorld optional )

Sets parent/child relationship with parent parameter. nil can be used to remove the Object from its parent.

The keepWorld optional parameter, false by default, dictates whether to maintain the child's world or local position and rotation. Keeping world will ensure the object doesn't move in the scene, adjusting its local position/rotation accordingly; keeping local will have the object move in the scene in order to maintain an equivalent local position/rotation relative to its new parent.

It's also a good practice to set child/parent relationships before setting positions.

local o = Object()
o:SetParent(Map) -- o is now a child of the map
-- (Map is an extension of Object)

Properties

Object's constant acceleration in world coordinates per second squared.

⚠️ Acceleration will only affect Object's position while Object.Physics is true.

-- Acceleration can be used to compensate gravity: 
myObject.Acceleration = -Config.ConstantAcceleration
-- myObject's acceleration is now the invert of 
-- Config.ConstantAcceleration, cancelling it.

Backward is a unit vector (vector with a length of 1). It determines which direction is "backward" for the Object.

Setting it is a way to rotate the Object.

The combined bounciness of 2 Objects in contact represents how much of the moving Object's velocity is produced after being in contact with the colliding Object, it is a rate between 0 (no bounce) and 1 (100% of the velocity bounced). Values higher than 1 are allowed and will create an increasing momentum at each bounce (try at your own risk).

[Object.Bounciness] can be set per-face by providing a table with any combination of the following keys : right, left, front, back, top, bottom, other.
For example, to set the bounciness on the side faces of an object's collider to 0.2 and 0 on top and bottom faces, you could set, object.Bounciness = { top=0, bottom=0, other=0.2 }.

Returns number of child Objects.

Collision groups the Object collides with.

By default:
- Objects collide with the Map and other Objects
- Players collide with the Map and the Objects

That can all be configured differently depending on your needs.

local object = Object()

-- It's not mandatory to change Physics value.
-- (default value is PhysicsMode.Static)
-- An object with Physics set to PhysicsMode.Static contributes 
-- to the physics simulation as a static item (can't be moved)
object.Physics = PhysicsMode.Dynamic

-- making an object collide with the Map and Players
object.CollidesWithGroups = Map.CollisionGroups + Player.CollisionGroups

-- for an Object to collide with other objects only
-- (won't collide with the map)
object.CollidesWithGroups = object.CollisionGroups

-- for Player (local player) to collide with other players and the Map
Player.CollidesWithGroups = Map.CollisionGroups + Player.CollisionGroups

-- making sure 2 objects collide with each others
-- NOTE: by default:
-- Map.CollisionGroups == {1},
-- Player.CollisionGroups == {2},
-- Object.CollisionGroups == {3}
local object1 = Object()
local object2 = Object()
object1.CollisionGroups = {5}
object2.CollisionGroups = {5}
object1.CollidesWithGroups = {1, 5} -- collides with Map + objects in group 5
object2.CollidesWithGroups = {1, 5} -- collides with Map + objects in group 5

-- would also work this way if you don't 
-- remember Map's group (which can be changed too by the way)
object1.CollidesWithGroups = Map.CollisionGroups + {5}

All Objects have a collision box that represents the space occupied in the scene with regards to collisions. For Shapes and Players, the collision box is updated with their bounding box. For Objects, it is a 1-cube by default after physics was enabled for the first time.

Collision groups the Object belongs to.

⚠️ It doesn't mean the Object will collide with other Objects in these groups.

If the Object belongs to group number 3 for example, it means all Objects that have group number 3 in their Object.CollidesWithGroups property will collide with it.

By default:
- Objects collide with the Map and other Objects
- Players collide with the Map only

That can all be configured differently depening on your needs.

local object1 = Object()
local object2 = Object()
-- It's not mandatory to set Physics to true
-- An object with Physics set to false contributes to the
-- physics simulation as a static item (can't be moved)
object1.Physics = true
object2.Physics = true

-- making sure 2 objects collide with each other
-- NOTE: by default:
-- Map.CollisionGroups == {1},
-- Player.CollisionGroups == {2},
-- Object.CollisionGroups == {3}
object1.CollisionGroups = {5}
object2.CollisionGroups = {5}
object1.CollidesWithGroups = {1, 5} -- collides with Map + objects in group 5
object2.CollidesWithGroups = {1, 5} -- collides with Map + objects in group 5

-- would also work this way if you don't 
-- remember Map's group (which can be changed too by the way)
object1.CollidesWithGroups = Map.CollisionGroups + {5}

-- making an object collides with the Map and Players
local object = Object()
object.CollidesWithGroups = Map.CollisionGroups + Player.CollisionGroups

-- for Player (local player) to collide with other players and the Map
Player.CollidesWithGroups = Map.CollisionGroups + Player.CollisionGroups

Down is a unit vector (vector with a length of 1). It determines which direction is "down" for the Object.

Setting it is a way to rotate the Object.

Forward is a unit vector (vector with a length of 1). It determines which direction is "forward" for the Object.

Setting it is a way to rotate the Object.

The combined friction of 2 Objects in contact represents how much the moving Object will be able to slide along the colliding Object.

It is a rate between 0 (full slide, no friction) and 1 (maximum friction). Values equal to or lower than 0 will keep or increase momentum, like sliding on ice. Values higher than 1 means a faster stop, up to a value of 2 to ensure a full stop on contact regardless of the colliding Object's own friction.

[Object.Friction] can be set per-face by providing a table with any combination of the following keys : right, left, front, back, top, bottom, other.
For example, to set the friction on the bottom face of an object's collider to 0 and 0.2 on every other faces, you could set, object.Friction = { bottom=0, other=0.2 }.

Can be set to true for the Object to be hidden recursively, meaning Object and all of its children are hidden.

Nothing else changes, the Object remains in the scene and it keeps being affected by the simulation (collisions, etc.).

Can be set to true for the Object to be hidden individually.

Nothing else changes, the Object remains in the scene and it keeps being affected by the simulation (collisions, etc.).

boolean IsOnGround read-only

true when the Object is not falling.

⚠️ IsOnGround only makes sense when Object.Physics is true.

Left is a unit vector (vector with a length of 1). It determines which direction is "left" for the Object.

Setting it is a way to rotate the Object.

Local position of the Object relative to its parent.

All of Object's ancestors local transformations are combined to obtain the Object "world position" (Object.Position), the Object's final position.

Local rotation of the Object relative to its parent.

All of Object's ancestors local transformations are combined to obtain the "world rotation" (Object.Rotation), the Object's final rotation.

Scale of the Object, in its parent.

Nested Object local scales are combined to obtain the "world scale" (Object.LossyScale), the Object's final scale.

myObject.LocalScale = 2 -- the Object is now 2 times bigger
topLevelObject.LocalScale = 2
local o = Object()
o.LocalScale = 0.5
topLevelObject:AddChild(o) -- o becomes a child of topLevelObject
-- o ends up being displayed with a scale of 1
number LossyScale read-only

Convenience property that attempts to match the actual world scale as much as it can. Note that Objects that have multiple levels of nested rotations and scales will return a skewed lossy scale.

The mass of the Object determines how much a given force can move it and whether or not another object can be pushed by it. It cannot be zero, a neutral mass is a mass of 1.

Be aware, this Motion property is a hack regarding laws of physics. (sorry Isaac)

But it's very practical to move objects without worrying about forces at play.

This is what's being used by default when you're moving around with your avatar (see Client.DirectionalPad). It's the reason why you can stop moving horizontally while in the air.

Basically, Motion is an instantaneous displacement that contributes to moving Object every frame, without changing Object.Velocity directly.

Motion is expressed in world coordinates per second.

⚠️ Motion will only affect Object's position while Object.Physics is true. Whenever it is set to false, Motion is set to {0,0,0}.

local speed = 10
myObject.Motion = Camera.Forward * speed
-- myObject will move in the same direction the camera is currently facing.
-- If the Camera rotates after this, it won't change where myObject is heading.

nil by default. Can be set to a function that will be triggered every frame where this object remains in contact with another object.

Like OnCollisionBegin, this function has 3 arguments: self, other, normal.

nil by default. Can be set to a function that will be triggered when this object begins a collision with another object.

The function is called with 3 parameters:
- the object the callback was set for,
- the other actor in the collision,
- the world normal of the hit surface.

Note: it's not necessary to use all 3 parameters.

object.OnCollisionBegin = function(self, other, normal)
  print("collision began between", self, " and ", other, " with world normal ", normal)
end

nil by default. Can be set to a function that will be triggered when the Object ends colliding with another Object.

The function is called with 2 parameters: the object the callback was set for and the other actor in the collision.

object.OnCollisionEnd = function(self, other)
  print("collision ended between", self, "and", other)
end

Sets the simulation mode for this object, it can be one of the following:
- PhysicsMode.Disabled: excluded from all physics features.
- PhysicsMode.Trigger: Object's collision box is available for casts and collision callbacks, and is passed through by other dynamic objects.
- PhysicsMode.TriggerPerBlock: if Object is a Shape, its model blocks are available for casts and collision callbacks, and is passed through by other dynamic objects.
- PhysicsMode.Static: Object's collision box is available for casts, collision callbacks, and acts as an obstacle for other dynamic objects.
- PhysicsMode.StaticPerBlock: if Object is a Shape, its model blocks are available for casts, collision callbacks, and act as obstacles for other dynamic objects.
- PhysicsMode.Dynamic: Object's world-aligned collision box is available for casts, collision callbacks, may act as obstacles for other dynamic objects, and is itself fully simulated.

By default, objects are set to PhysicsMode.Static.

You may use Dev.DisplayColliders to visualize each object's collision settings.

⚠️ When set to PhysicsMode.Disabled, Object.Velocity & Object.Motion are set to {0,0,0}.

Position of the Object in the world.

local o = Object()
-- places the object where the local player is
o.Position = Player.Position

Right is a unit vector (vector with a length of 1). It determines which direction is "right" for the Object.

Setting it is a way to rotate the Object.

Rotation of the Object in the world (as seen on screen).

While it usually works for simple operations (like Rotation.X = Rotation.X + someAngle), we advise you to use Number3.Rotate to rotate an object around X, Y & Z axis.

You can also set unit vectors like Object.Up, Object.Right or Object.Forward to orient your object.

local o = Object()
o.Rotation = {0, math.pi, 0}
-- o revolved half a turn on Y axis

-- another way to rotate the object:
o.Forward:Rotate({0, 0, math.pi / 2})
o.Forward = Camera.Forward

Size in world units of the shadow cookie projected under the Object, default is 0.0 (disabled).
The shadow cookie, also called blob shadow, is a square texture acting as a cheap alternative to projected shadows.

If this value is strictly positive, shadow cookies will be displayed when:
- the scene has no light source,
- the scene has light sources, but they are disabled because the client is using lower quality settings

Shadow cookies can be used as a fallback to your scene shadows for players with low quality settings, of course, you can also use them instead of shadows as a design choice.

Tick is a function executed ~30 times per second when set (nil by default). Provides the Object and elapsed time in seconds as parameters.

-- executed ~30 times per second on each user device
myObject.Tick = function(object, dt)
  print("elapsed:", dt, "seconds")
end

Up is a unit vector (vector with a length of 1). It determines which direction is "up" for the Object.

Setting it is a way to rotate the Object.

Velocity of the Object in world coordinates per second.

⚠️ Velocity will only affect Object's position while Object.Physics is true. Whenever it is set to false, Velocity is set to {0,0,0}.

-- makes myObject jump:
myObject.Velocity.Y = 100