KRONO (ChronoSchema) | <9 ms C++ Header Hot-Patcher & Win32 MEM_WRITE_WATCH Time-Machine for Unreal Engine 5.8
KRONO eliminates two of the biggest daily time-wasters in Unreal Engine 5.8 with zero setup required:
1. Instant C++ Variable Updates (No Editor Restarts)Add or edit variables (float, double, int32, bool, FString) in your C++ .h file and press Ctrl+S.
They appear in your Details Panel and Blueprints in under 9 milliseconds—even while your game is running.
No closing the Editor to recompile.
2. Instant Gameplay Rewind (No Restarting Play-In-Editor)Testing a jump, movement tweak, or physics bug in PIE?
Click “<< -3s” or “< -1s” on the top toolbar to rewind your character and physics objects back in time so you can re-test the exact same moment instantly.
3. Works Out of the BoxJust enable the plugin.
No extra code, no Blueprint wiring, and no special Actors to place in your level.
TECHNICAL OVERVIEW
Accelerate reflected C++ property iteration. Eliminate unnecessary Editor restarts for supported header changes. Rewind Play-In-Editor (PIE) state and tracked virtual memory pages to reproduce and inspect gameplay bugs.
KRONO (ChronoSchema) combines a sub-9 ms C++ header reflection hot-patcher with a 600-frame OS-tracked virtual memory time-machine, built natively for Unreal Engine 5.8 (Win64) with zero third-party DLL dependencies.
Unreal Engine’s Live Coding patches compiled .cpp function bodies while the Editor is running. However, adding new UPROPERTY fields, changing default values in .h files, or adjusting Category metadata still traditionally requires running Unreal Header Tool (UHT) or restarting the Editor.
KRONO targets this reflection iteration gap:
It dynamically injects, updates, or hides supported primitive and string UPROPERTY fields directly on live UClass property chains, Class Default Objects (CDOs), derived Blueprints, and active level instances in under 9 milliseconds upon pressing Ctrl+S.
It operates independently of Live Coding (including when Live Coding is disabled) for exposing and tuning reflected properties in Blueprints and Details Panels.
Transparent Boundary: KRONO patches Unreal’s reflection layer and object memory without invoking the MSVC compiler. When you write new .cpp implementation code that references a newly added header variable by its C++ identifier, you compile the .cpp changes via Live Coding (Ctrl+Alt+F11) or your IDE as normal.
ChronoSchemaEditor
Live UPROPERTY Injection, Updates & ReconciliationSupported Types: float (FFloatProperty), double (FDoubleProperty), int32 (FIntProperty), bool (FBoolProperty), and FString (FStrProperty).
Save any watched project .h file with Ctrl+S to trigger live schema reconciliation in under 9 ms.
Add New Properties: Appends new FProperty nodes to the tail of UClass::ChildProperties so existing compiled C++ member offsets remain 100% intact.
Edit Defaults & Categories Live: Changing a default value (e.g., = 6.0f) or Category = “…” in your .h file and pressing Ctrl+S immediately updates the CDO, live Actor instances, and open Details Panels.
Delete Reconciliation: Removing a hot-patched UPROPERTY from your .h file and saving immediately unlinks it from the Details Panel and derived Blueprints.
If you close and reopen the Unreal Editor (or switch maps) before running a full C++ build in Visual Studio/Rider, KRONO automatically scans your project .h files on Editor startup and Map Load (OnMapOpened) to re-apply your uncompiled UPROPERTY schemas and default values.
ChronoSchemaRuntime
OS Kernel Dirty-Page Tracking (Win32 MEM_WRITE_WATCH)Reserves a 64 MB page-aligned virtual memory arena (16,384 pages at 4 KB granularity) using Win32 VirtualAlloc with MEM_WRITE_WATCH.
Queries the Windows Kernel Memory Management Unit (MMU) each tick via GetWriteWatch and ResetWriteWatch to identify only the 4 KB pages mutated during that frame.
Captures 4 KB page deltas (PreMutationBytes vs. PostMutationBytes) across a 600-frame circular ring buffer (10.0 seconds at 60 FPS) in under 0.2 ms per tick.
UChronoTimeMachineSubsystem is a UTickableWorldSubsystem that initializes automatically in every PIE world—no manager Actor needs to be placed in your level.
Automatically discovers movable Pawns/Characters and physics-enabled Actors in PIE, binding each to a dedicated 4 KB hardware page.
Rewinding time via the toolbar, Studio Cockpit, oscilloscope scrubber, or Blueprints restores the 4 KB pages and teleports tracked Actors (ETeleportType::TeleportPhysics) back to their historical location, rotation, control rotation, and velocity.
For custom deterministic simulation structs or manual memory tracking, KRONO exposes 10 Blueprint-callable functions under “Chrono Schema | Time Machine”:
RewindFrames
GetAvailableRewindFrames
SetRecordingPaused
IsRecordingPaused
AllocateTrackedPage
WriteTrackedFloat
ReadTrackedFloat
GetRecordedFrameCount
GetLastTickDirtyPages
GetAllocatedPageCount
Slate UI
Integrated Level Editor Toolbar & Dockable Cockpit60 Hz Dirty-Page Oscilloscope & Interactive Scrubber: Visualizes per-tick clean (cyan) vs. mutated (magenta) 4 KB page bursts across the 600-frame ring buffer. Click or drag left on the waveform to scrub backward in PIE.
256-Cell (32x8) 4 KB Page Matrix Visualizer: Live memory grid displaying standby pages, allocated clean pages, and active mutation heatmaps.
One-Click Transport Controls: Instant buttons for Force Scan & Hot-Patch (.h), Step Back -1 Frame, Rewind -1s (60f), and Rewind -3s (180f).
Console & Automation Endpoints: Includes Chrono.HotPatchHeaders, Chrono.RewindFrames <N>, Chrono.MCP.HotPatch, and Chrono.MCP.Rewind <N>.
ChronoSchemaRuntime (Runtime)
ChronoSchemaEditor (Editor)
10 core C++ classes and structs across 15 source/build files.
Local single-process memory tracking and PIE rewind (network replication is not supported).
Zero third-party DLL dependencies; 100% native Unreal Engine 5.8 C++20 and Win32 Kernel Virtual Memory APIs.
Development Platform: Win64
Target Build Platforms: Win64 (Editor, Development, Shipping)
Official Documentation URL: