JSON based format for storing UObject reflection data, vtable layouts, version information, among other things extracted from compiled Unreal Engine binaries.

Dump from running process:

cargo run --release -- --pid 12345 output.jmap

Dump from existing full-memory minidump:

cargo run --release -- --minidump FSD-Win64-Shipping.DMP output.jmap

Or output to .usmap:

cargo run --release -- --minidump FSD-Win64-Shipping.DMP output.usmap

In case of message "Error: Resolution: EngineVersion: expected at least one value", set an environment variable for patternsleuth library:

$env:PATTERNSLEUTH_RES_EngineVersion="ver" e.g. $env:PATTERNSLEUTH_RES_EngineVersion="5.6"

In case of message like "Error: Resolution: FNamePool: found 2 unique values [7FF6DB379E00, 7FFDB90C6140]", set an environment variable for patternsleuth library:

$env:PATTERNSLEUTH_RES_FNamePool=0x<one of the found FNamePool values> e.g. $env:PATTERNSLEUTH_RES_FNamePool=0x7FF6DB379E00

The output JSON is a superset of .usmap and contains enough information to fully reconstruct a matching project in the Unreal Engine editor.

It contains:

• Reflection data for: Classes, Functions, Structs, Enums, etc.
• Class Default Objects (CDOs) and property values

It also does light VTables analysis and dumps approximate VTables for all UObjects found.

Crate for reading/writing .jmap files.

Crate for reading/writing .usmap files (legacy binary format created by https://github.com/TheNaeem/UnrealMappingsDumper still used by many tools today).

Binary Ninja plugin to reconstruct classes and structs from reflection data.

For development and debugging purposes, it is handy to make a full memory dump of the game. Windows makes this really easy via task manager:

After a moment or two the dump should complete: