Implementation:Google deepmind Mujoco mj saveModel

Knowledge Sources	MuJoCo MuJoCo API Reference
Domains	Model_IO, Serialization
Last Updated	2026-02-15 06:00 GMT

Overview

Concrete tool for saving a compiled MuJoCo model to binary MJB format provided by the MuJoCo C API.

Description

The mj_saveModel function serializes a compiled mjModel to either a binary file or a memory buffer. It writes a standard header with version checks, then all size fields, options, visual settings, statistics, and all data arrays using X-macro iteration.

Usage

Call after successful model compilation to save the binary for fast future loading.

Code Reference

Source Location

• Repository: mujoco
• File: src/engine/engine_io.c
• Lines: 481-533

Signature

void mj_saveModel(const mjModel* m, const char* filename,
                  void* buffer, int buffer_sz);

Import

#include <mujoco/mujoco.h>

I/O Contract

Inputs

Name	Type	Required	Description
m	const mjModel*	Yes	Compiled model to save
filename	const char*	No	Output MJB file path (NULL if using buffer)
buffer	void*	No	Memory buffer alternative (NULL if using file)
buffer_sz	int	No	Buffer size in bytes

Outputs

Name	Type	Description
file/buffer	binary	MJB binary data with header and all model arrays

Usage Examples

#include <mujoco/mujoco.h>

// Load from XML, save as binary
mjModel* m = mj_loadXML("humanoid.xml", NULL, error, 1000);
if (m) {
    mj_saveModel(m, "humanoid.mjb", NULL, 0);
    mj_deleteModel(m);
}

Related Pages

Implements Principle

• Principle:Google_deepmind_Mujoco_Model_Binary_Export