OBJ Sequence → Alembic

Free app to convert an OBJ sequence to Alembic (.abc) — a batch OBJ to ABC mesh cache converter for macOS and Windows.

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Batch-convert a folder of numbered OBJ files into a single animated Alembic (.abc) mesh cache — with UV support, changing-topology meshes, and fast parallel conversion. Drag in a folder of OBJs, get one .abc you can import into Blender, Maya, Houdini, or Cinema 4D.

This tool is meant for folders full of numbered OBJ files, such as:

0000.obj
0001.obj
0002.obj
...

Choose your platform

This repository ships a native app for each operating system. Pick the folder for your OS — each one is self-contained, with its own app, build scripts, and instructions.

Platform	Folder	Start here
🍎 macOS 13+	macos/	macOS guide — download OBJ Sequence to Alembic.app
🪟 Windows 10/11	windows/	Windows guide — download OBJ Sequence to Alembic.exe

Prebuilt downloads are published on the GitHub Releases page (macOS .zip and Windows .zip). End users do not need Python, CMake, or a compiler to run a release build — those are only needed if you build from source.

What it exports

The Import Detected Data panel in the app scans the first OBJ frame and shows a checkbox for every optional data type it finds, so you can turn each one on or off per conversion. UVs are included by default (matching prior versions); normals and vertex colors are opt-in.

Data	Exported
Animated vertex positions	✅
Face indices and face counts	✅
Face-varying UVs (when OBJ vt data exists)	✅ default on
Face-varying normals (when OBJ vn data exists)	✅ opt-in
Vertex colors (v x y z r g b extension)	✅ opt-in
Framerate / time sampling	✅
Per-frame changing topology	✅
Materials or .mtl files	❌
Texture paths	❌
OBJ groups or object names	❌
Multiple independent meshes in one OBJ	❌

Changing topology

Each frame is written with its own topology, so sequences whose vertex and face counts change over time — fracture, fluid, or remeshing simulations — are preserved correctly rather than frozen to the first frame. Control file size by exporting fewer frames or simplifying the mesh upstream in your DCC.

Command line

Both platforms include the same converter as a command-line tool. From inside the platform folder:

# macOS
bin/Objs2Abc -i head-poses -o output/head-poses.abc -f 24 -n Head

# Windows
.\bin\Objs2Abc.exe -i .\head-poses -o .\output\head-poses.abc -f 24 -n Head

Keywords

OBJ to Alembic · convert OBJ sequence to Alembic · OBJ to ABC converter · batch OBJ converter · OBJ sequence to ABC · Alembic mesh cache · OBJ animation to Alembic · macOS Alembic converter · Windows Alembic converter · OBJ frame sequence · changing topology Alembic · Blender / Maya / Houdini / Cinema 4D Alembic import.

Credits

This project builds on the original convert_objs_to_abc by Liyou, which provides the core OBJ-to-Alembic conversion. This fork adds native macOS and Windows apps and command-line builds, a Tk GUI with progress reporting, changing-topology support, and a number of correctness and performance fixes.

License

Released under the MIT License. See LICENSE. Original work Copyright (c) 2022 Liyou.