.BLEND

Introduction

A BLEND file is everything Blender has open, saved to disc: scenes, objects, meshes, materials, animation, the layout of the windows and more. Blender writes its internal data structures almost directly from memory, and stores a description of those structures in the same file. That description lets any version of Blender read a file written by another, even when the structures have changed.

Blender can compress the file when saving. Older versions used gzip; Blender 3.0 and later use Zstandard.

Software

• Blender (Windows, macOS, Linux)
• Unity (Windows, macOS, Linux), through an installed copy of Blender
• Godot (Windows, macOS, Linux), through an installed copy of Blender

Structure

Files written by Blender 4 and earlier begin with a 12-byte header: the text BLENDER, a character for the pointer size (_ for 32-bit, - for 64-bit), a character for the byte order (v for little-endian, V for big-endian) and three digits of version, such as 293. A series of file blocks follows. Each block has a short code, the size of its data, the memory address the data had when it was saved, an index into the structure list and a count of structures, then the data itself.

The DNA1 block holds the SDNA: the names, types and layouts of every structure Blender saves. Pointers between blocks are the saved memory addresses, which a reader matches to the blocks that carry them. The ENDB block ends the file.