World UI and draw calls in VRChat

Short answer: a world-space canvas keeps costing draw calls and raycasts while it is enabled, wherever the player stands. Disable the ones that are out of range.

A canvas nobody can see still costs something

Unity does not know that your notice board is on the other side of the map. As long as its Canvas component is enabled, it is batched, submitted and — if it has a GraphicRaycaster — tested against pointer input.

In a world with twenty information panels, menus and signs, that is twenty canvases paying rent permanently so that the two the player is actually near can be read.

Disable the canvas, not the GameObject

This distinction matters more than it looks.

SetActive(false) on the parent object re-runs OnEnable across the whole hierarchy when it comes back — including any Udon behaviour attached to it, which may reset state you cared about. Disabling the Canvas component alone stops the rendering and leaves everything else untouched.

The same applies to the GraphicRaycaster: turning it off removes the input cost without destroying anything.

What distance should I use?

Whatever distance the UI stops being readable at. For a wall panel with body text, that is often 8 to 15 metres. For a large sign, considerably more.

One trap: if you hide and show at exactly the same distance, a player standing on the boundary makes the UI flicker on and off every frame. Add a margin — hide at, say, 12 metres but only show again at 10.

Doing it without writing Udon

FOS UI Culling scans your scene, attaches a target to every world-space canvas and drives them all from one manager.

• Default distance for the whole world, overridable per UI.
• Hysteresis, the margin described above, to stop boundary flicker.
• Checks per frame — four by default — so a world with a hundred UIs spreads its tests instead of doing them all at once.
• An optional line of sight pass, off by default, for UIs behind walls.

The pack is free and requires only FOS Essentials Core.