FF7 Rebirth NPC Motion

A ReShade add-on for FINAL FANTASY VII REBIRTH (PC) that fixes the motion vectors of townspeople and other characters whose animation the game throttles, so DLSS (and the game's TAA and motion blur) no longer smears their outlines, and lets the game's animation budget interpolate them so they move every frame.

The problem

Rebirth (Unreal Engine 4.26) limits how much time it spends on character animation with Unreal's animation budget allocator: characters at medium distance are animated only every second or third frame, and Square Enix turned the budget's interpolation off (a.Budget.MaxInterpolatedComponents=0). Every skinned mesh keeps two bone buffers on the GPU, the current pose and the previous one, and the velocity pass compares them. On a frame without an animation update, UE 4.26 still binds the older pose as the previous one, so the motion vectors repeat the last update's movement while the character stands still on screen. In Kalm, 37-64 of about 270 character draws per frame carried motion that had not happened, up to 4 pixels at 1080p render resolution. DLSS then reprojects those characters' history from the wrong place. (UE 4.27 added the missing check.)

What the add-on does

• Motion vectors: at every draw whose vertex shader reads PreviousBoneMatrices, if the draw's BoneMatrices buffer was already a current bone buffer in the previous frame (the game allocates a new one for every pose update), the mesh was not updated, so the add-on points the draw's PreviousBoneMatrices descriptor at the current bones. The character's skinning motion is zero for that frame; its movement through the world still produces motion vectors. Shaders are recognised by name (DXIL reflection), not by hash.
• Interpolation (InterpolatedCharacters): before the world loads, the add-on sets the budget's MaxInterpolatedComponents (both of the game's budget profiles) so throttled characters get an interpolated pose on the frames they are not evaluated. In Kalm this left 5 of about 207 character draws per frame without a new pose, at nearly the same frame rate (100-102 fps against about 104 before, though measured with different DLSS presets). Switching the budget off completely (AnimationBudget=0) animates everyone every frame but made the game CPU-bound (about 60 instead of 100 fps on an i7-13700KF).

Installation

Requires ReShade 6.x with full add-on support for ff7rebirth_.exe (DirectX 12) and the FF7 Rebirth Hair Fix (the add-on uses its FF7RebirthHairFix\dxcompiler.dll; a FF7RebirthNpcMotion\dxcompiler.dll next to the add-on works too). Copy FF7RebirthNpcMotion.addon64 and FF7RebirthNpcMotion.ini into ...\FINAL FANTASY VII REBIRTH\End\Binaries\Win64.

Settings

FF7RebirthNpcMotion.ini (the ReShade overlay's Add-ons tab shows per-frame counters):

Key	Default	Meaning
Enabled	1	Fix the motion vectors of characters that were not updated this frame.
ToggleKey	118 (F7)	Virtual-key code that switches the fix on and off; 0 = none.
InterpolatedCharacters	64	Characters the animation budget may interpolate; -1 = the game's value (0). Startup.
AnimationBudget	1	0 = switch the game's animation budget off at startup (expensive, see above).
LogStats	0	1 = write counters and the frame rate to ReShade.log every 600 frames.

Building

Visual Studio 2022 or newer with the C++ x64 tools: .\build.ps1 builds build\FF7RebirthNpcMotion.addon64 and build\reflect_test.exe (checks the bone register lookup on shaders saved from a capture).

Investigation

docs/recon.md is the log: RenderDoc captures of Kalm (the game needs a small in-memory patch to run under RenderDoc, tools/psopatch.py), the base pass velocity, the bone buffers across three consecutive frames, the engine code that binds them, and the in-game measurements. tools/ holds the capture and analysis scripts.

License

MIT; see LICENSE. src/descriptors.* is adapted from ReShade's descriptor tracking example (Copyright (C) 2021 Patrick Mours, BSD-3-Clause OR MIT); third_party/reshade and third_party/imgui carry their own licenses. FINAL FANTASY VII REBIRTH is a trademark of Square Enix; this project is not affiliated with or endorsed by Square Enix.