🧱 Occlusion¶
Occlusion makes a voice muffled when world geometry sits between the speaker and the local listener. Walk behind a wall and the other players fade and get muddy, exactly what you'd expect.
It's done per physical material: glass muffles differently than concrete. Surfaces between speaker and listener stack.
How it works¶
On each listener's machine, EPVC periodically traces from the speaker to the listener and collects the surfaces in between. For every surface hit:
- Volume multipliers stack (multiplicatively) — more walls = quieter.
- The most muffled low-pass wins — the thickest surface sets the muddiness.
The result is blended in/out smoothly so it never pops.
Note
Occlusion is evaluated per emitter, from where each one actually sits. A radio behind a wall is muffled even when the speaker is standing in the open, and each emitter uses the config it plays on (the receiver's Output Configuration when it has one).
1. Enable it on the config¶
In your ProximityVoiceConfig asset:
| Property | Description |
|---|---|
Enable Occlusion |
Master switch for muffling through geometry. |
Occlusion Trace Channel |
Trace channel used to collect surfaces. Set occluding meshes to Overlap (or Block) on this channel. Defaults to Visibility. |
Occluded Volume Multiplier |
Fallback volume kept through a surface with no matching material (1 = unchanged, 0 = silent). |
Occluded Low Pass Frequency |
Fallback low-pass cutoff (Hz) for an unmatched surface. Lower = more muffled. |
Occlusion Interp Speed |
How fast the muffle blends in/out. Higher = snappier. |
Occlusion Trace Interval |
Seconds between occlusion traces. Lower = more responsive, more cost. |
2. Author per-material presets¶
Occlusion Materials is a list of presets, each keyed to a Physical Material:
| Property | Description |
|---|---|
Physical Material |
The surface this entry matches. Assign the same physical material to your glass/concrete/etc. meshes. |
Volume Multiplier |
Volume kept passing through this surface (1 = unchanged, 0 = silent). Stacks multiplicatively. |
Low Pass Frequency |
Low-pass cutoff (Hz) through this surface. Lower = more muffled. Most muffled surface wins. |
Any surface not in the list uses the Occluded Volume Multiplier / Occluded Low Pass Frequency fallbacks above.
3. Set up your world¶
- Create/assign Physical Materials to the meshes you want to occlude (e.g.
PM_Glass,PM_Concrete). - Make sure those meshes respond to the Occlusion Trace Channel (Overlap or Block).
- Add matching entries in the config's
Occlusion Materials.
Tip
Thin glass → high Volume Multiplier (stays loud) but a mid Low Pass Frequency (a little muffled). Thick concrete → low Volume Multiplier and low Low Pass Frequency (quiet and muddy).
Note
You can read how muffled a speaker currently is with Get Occlusion Amount on their component (0 = clear, 1 = fully occluded), handy for a UI indicator or the Debug Overlay.