AI nav walking doesn't allow clients to set a "Base" for the character (SetBase from UpdateFloorFromAdjustment), so there is no floor result on frames where there is a net update. This causes simulated movement to fail for that frame, so no movement occurs, but later frames between updates from the server can use the last floor (found after the failed move)

A fix might be to update a floor before movement even if the base isn't allowed when nav walking on the server. However it's not clear why the AI guys didn't want a base to be set on clients, this would break other things like standing on moving platforms etc.

Steps to Reproduce

Have AI characters use nav walking on the server, which causes them to use normal walking on clients. Can be done in PIE w/ dedicated server.

Have AI move in straight lines at consistent but low speeds.

Set the framerate to ~20 (t.maxfps 20)

Notice some jitter in position on the client. Does not reproduce w/out a server or on the listen server.

(See for a small sample project)


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Won't Fix
ComponentUE - AI
Affects Versions4.194.204.21
CreatedAug 23, 2018
ResolvedAug 18, 2021
UpdatedAug 18, 2021