Mitsuba Scene Description (MSD)

Disclaimer: Expect rough edges and frequent changes to the API.

Typed, autocompletable Python dataclasses for composing Mitsuba 3 scenes programmatically. Build a scene with normal Python objects and call mi.load_dict(scene.to_dict()) to render.

The plugin classes are generated at install time by scraping the official Mitsuba plugin reference, so they always match your installed Mitsuba version.

Installation

pip install mitsuba-scene-description

During installation the build hook detects your Mitsuba version and generates typed classes for every plugin in the docs. The version is resolved in this order:

Priority	Source	Example
1	MITSUBA_VERSION env var	MITSUBA_VERSION=3.7.1 pip install .
2	Installed mitsuba package	automatic if mitsuba is already installed
3	Built-in fallback (3.7.1)	no extra setup needed

Development install

pip install -e .

Usage

import mitsuba_scene_description as msd
import mitsuba as mi

mi.set_variant("llvm_ad_rgb")

# Define components
diffuse = msd.SmoothDiffuseMaterial(reflectance=msd.RGB([0.8, 0.2, 0.2]))
ball = msd.Sphere(
    radius=1.0,
    bsdf=diffuse,
    to_world=msd.Transform().translate(0, 0, 3).scale(0.4),
)
cam = msd.PerspectivePinholeCamera(
    fov=45,
    to_world=msd.Transform().look_at(
        origin=[0, 1, -6], target=[0, 0, 0], up=[0, 1, 0]
    ),
)
integrator = msd.PathTracer()
emitter = msd.ConstantEnvironmentEmitter()

Constructing scenes

Pass components directly to Scene:

scene = msd.Scene(
    integrator=integrator,
    sensors=cam,  # also accepts a list for multi-sensor setups
    shapes={"ball": ball},
    emitters={"sun": emitter},
)

Or use the fluent SceneBuilder:

scene = (
    msd.SceneBuilder()
    .integrator(integrator)
    .sensor(cam)
    .shape("ball", ball)
    .emitter("sun", emitter)
    .build()
)

Rendering

mi_scene = mi.load_dict(scene.to_dict())
rndr = mi.render(mi_scene)
mi.util.write_bitmap("test.png", rndr)

scene.to_dict() produces a plain dict ready for mi.load_dict:

{'ball': {'bsdf': {'reflectance': {'type': 'rgb', 'value': [0.8, 0.2, 0.2]},
                   'type': 'diffuse'},
          'radius': 1.0,
          'to_world': Transform[
  matrix=[[0.4, 0, 0, 0],
          [0, 0.4, 0, 0],
          [0, 0, 0.4, 1.2],
          [0, 0, 0, 1]],
  ...
],
          'type': 'sphere'},
 'integrator': {'type': 'path'},
 'sensor': {'fov': 45,
            'to_world': Transform[...],
            'type': 'perspective'},
 'sun': {'type': 'constant'},
 'type': 'scene'}

Core types

Type	Description
Plugin	Base dataclass for all plugins
Scene	Top-level scene container
SceneBuilder	Fluent builder for Scene
Transform	Chainable affine transform builder (translate, scale, rotate, look_at, matrix)
ProjectiveTransform	Extends Transform with perspective/orthographic (Mitsuba >= 3.7)
RGB	RGB color value
Ref	Reference to a named asset

Generated plugin categories

Every Mitsuba plugin category gets its own module with a typed dataclass per plugin:

BSDFs, Emitters, Films, Integrators, Media, Phase functions, Reconstruction filters, Samplers, Sensors, Shapes, Spectra, Textures, Volumes.

All classes are re-exported from mitsuba_scene_description, so msd.Sphere, msd.PathTracer, etc. work directly.

Running the generator manually

If you want to regenerate the API outside of the build process:

pip install requests beautifulsoup4
python generator/generate_mitsuba_api.py --out mitsuba_scene_description

Pass --overview <url> to target a specific docs version.

License

MIT