Limits and refusals

Every ceiling in one place, and what every refusal message means.

Nothing here crashes a script. A verb that cannot do what you asked answers nil and a reason in plain words, and your script carries on.

local ok, why = self:move_to(0, 5, 0)
if not ok then
    print("could not move: " .. why)
end

---

Ceilings

Per slice

A slice is one event firing, or the script being loaded.

Limit	Value
Instruction units	50,000
World effects	8
Events sent (emit + send)	16
print lines	32
Length of one print line	512 bytes

A world effect is anything that changes the world: a move, a rotation, a tween, a spawn, a property write, a sound, a terrain stroke, a block edit, damage. Reads are free — raycast, players:list, world:clock, self:get and the whole of vec cost nothing.

Per script

Limit	Value
Memory	4 MB
Keys in one self:set	32
Animation layers	8
Locomotion overrides	16

Per object

Limit	Value
Scripts	8
Tags	16
Store keys	256
Store key length	256 bytes
Store value size	64 KB
Store total	1 MB

A personal HUD is tighter, because its memory lives on the central server for everyone, forever:

Limit	Value
Store keys	64
Store value size	8 KB
Store total	32 KB
All your HUDs together	1 MB

Per player, per experience

What one person keeps in a world — players.store. It lives on the central server and follows them between machines:

Limit	Value
Store keys	128
Store key length	256 bytes
Store value size	64 KB
Store total	256 KB
All your experiences together	16 MB

Per region

The region's shared memory — world.store — is one drawer for the whole world, not one per object:

Limit	Value
Store keys	4096
Store key length	256 bytes
Store value size	64 KB
Store total	8 MB

The loading screen

What world.loading accepts. Past any of these the call is refused with a reason, not silently trimmed — a screen that quietly dropped four of your twelve tips is a bug you would hunt in the wrong place.

Limit	Value
Headline	80 characters
Subtitle	160 characters
Tips	8
One tip	160 characters
Tip dwell	2–30 seconds
Background / logo, longest side	4096 px

Limit	Value
Active scripts	768
Script-made objects alive at once	256
Named actions	32
Objects one tagged query may return	256
Pieces in a copied group	64

http

What one world may send outside. The request count is generous because requests are cheap; the ceiling that actually binds is in bytes, because bandwidth is what costs.

Limit	Value
Requests a second	10, banking up to 60
Bytes a second	512 KB, banking up to 16 MB
Bytes a day	5 GB
Requests in the air, per script	8
Requests in the air, per world	64
Requests waiting for a slot	64
Body sent	64 KB
Answer accepted	256 KB
Time before it gives up	10 s (5 s to connect)
Headers	16, up to 1 KB each and 4 KB in total
URL	2 KB

The per-second budgets bank quiet time. A world that has been idle for a minute can fire all 60 at once — which is what makes forty players arriving together work — and then settles back to 10 a second.

A destination that fails 5 times in a row is left alone for 30 seconds, and calls to it answer http cooling immediately. A 404 is not a failure.

HUD stages

A stage is a live 3D render every frame — the most expensive thing a HUD can hold, by a wide margin.

Limit	Value
Stages in one HUD	4
Pieces on one stage	64
Parts in a set on the shelf	256

Over either of the first two, the HUD is refused with a reason. A menu backdrop is dozens of pieces, not a city.

A set counts as the one piece you wrote, however many parts it brings — the ceiling on those is the shelf's own, applied when you publish it.

Ranges

Thing	Range
Coordinates	±100 km
Scale	0.01 – 10,000
Velocity and push	up to 100 m/s
Tween length	0.05 – 600 s
Region radius	0.5 – 96 m
Raycast reach	up to 512 m
Spawn life	default 30 s, max 300 s (0 = while the region runs)
Rate of fire and cycle	0.05 – 5 s
Light radius	0 – 96 m
Sound volume	0 – 4
Sound pitch	0.25 – 4
Wind	up to 40 m/s
Terrain brush radius	0.5 – 64 m
Terrain brush strength	0 – 8 m
Animation speed	−8 to 8
Event payload	3 levels deep, 32 entries, 512-byte strings
Channel name	1 – 64 characters

---

What stops a script

Two very different outcomes.

The event is abandoned, the script lives

An ordinary mistake — indexing something that is nil, calling a method that does not exist, arithmetic on text. The error is written to your console and the next event runs normally.

The script is killed

Message	Meaning
script budget exceeded	one slice used more than 50,000 instruction units
script memory limit exceeded	the script went over 4 MB

It does not run again until you save it. Both mean the same thing in practice: a loop without an exit. Use a timer instead — a slice may not take long, but you may have as many slices as you like.

---

Refusal reasons

Anywhere

Reason	What happened
permission	this world, or this player, has not granted what the verb needs. See Permissions
too many commands	more than 8 world effects in one event
too many moves	the same, from a movement verb
read-only key	that property is not writable by scripts — see the list

Moving and physics

Reason	What happened
not dynamic	push or set_velocity on an object that is not a physics body. Set dynamic = true first
unknown part	that part was deleted, or never existed
look_at: target is not a direction	the target is directly above, directly below, or the object's own position

Memory

Reason	What happened
store full	the key ceiling is reached (256 per object, 4096 for the world). Existing keys still read, overwrite and delete
value too large	over 64 KB (8 KB on a HUD)

Carrying

Reason	What happened
permission	that player has not interacted with this object
socket	no attachment point by that name — see Sockets
child	hold the root of a group, not one of its pieces
held	somebody else has it
full	their hands are full
not held	drop on something nobody was carrying

Making things

Reason	What happened
too many spawned objects	the region already has 256 script-made objects alive
a spawn is made of one thing	you named more than one of shape, model, copy

Damage

Reason	What happened
this object has no max_health — it cannot be damaged	set max_health first. This is how a world says what is breakable

Terrain and blocks

Reason	What happened
invalid brush	radius or strength outside the allowed range
invalid position	outside the world
box too big	a fill covering too many cells — refused whole, and said now rather than half-done later

Modules

Reason	What happened
unknown module '…'	built-ins are self, events, players, vec, world, objects. For your own module, attach a sibling script with that name to the same object and re-save this one
cyclic require of module '…'	two of your modules require each other

---

Reading a refusal

Three shapes, and they mean different things:

local hit = world:raycast(...)

Answer	Meaning
a value	it worked
nil	a real answer meaning "nothing" — no hit, no such item, nobody here
nil, reason	the call could not be carried out

world:raycast returning plain nil is a clear line of sight, not an error. self.contents:get returning plain nil means there is no such item. Absent is an answer.

See also

• How scripts run — slices and budgets explained
• Reading errors — finding the line
• Permissions