Release notes

Being an experimental research framework, Mitsuba 3 does not strictly follow the Semantic Versioning convention. That said, we will strive to document breaking API changes in the release notes below.

Mitsuba 3.7.1

October 17, 2025

  • Upgrade Dr.Jit to version 1.2.0. This release brings several important improvements and several bug fixes:

    • Event API for fine-grained GPU kernel timing and synchronization, enabling better performance profiling.

    • Enhanced CUDA-OpenGL interoperability with simplified APIs for efficient data sharing between CUDA and OpenGL.

    • Register spilling to shared memory on CUDA backend, improving performance for complex kernels with high register pressure.

    • Memory view support for zero-copy data access from Python.

    The remainder lists Mitsuba-specific additions.

  • Improvements:

    • Improved bump and normal mapping with two important fixes for more robust and artifact-free rendering. Both the bumpmap and normalmap BSDFs now include: (1) Invalid normal flipping - ensures perturbed normals are always consistent with the geometric normal by flipping shading normals when needed, following the approach in Schüssler et al. 2017 [SchusslerHHD17]. (2) Microfacet-based shadowing - smooths shadow terminator artifacts using the shadowing function from Estevez et al. 2019 [ELS19]. Both features are enabled by default but can be disabled via the flip_invalid_normals and use_shadowing_function parameters for backwards compatibility. (commit e32d71807, contributed by Delio Vicini).

    • Improved sunsky documentation. (PR #1743, contributed by Mattéo Santini).

    • Added support for vcalls of Texture. (commit 6b1603c77).

    • Added Python bindings for field<T> types. (PR #1736, contributed by Delio Vicini).

    • Allow multiple Python objects to refer to the same Object*. (PR #1740).

  • Bug fixes:

    • Fixed bug with unintentional reordering of channels when serializing and deserializing a Bitmap with more than 10 channels. (commit e84b18f, contributed by Sebastian Winberg).

    • Fixed hide_emitters behavior for area emitters in path integrator and all other integrators. (commits 3c3bf14c, 0755134e0, c967a0a24).

    • Fixed KDTree reference counting and shutdown procedure. (commit 14c8c9763).

    • Fixed compilation issues of the KDTree. (commit 65b38126b).

    • Prevent NaN values for normals of triangles with zero area. (PR #1733, contributed by Delio Vicini).

    • Prevent users updating the UniformSpectrum with a float of size different than 1. (PR #1722, contributed by Mattéo Santini).

    • Added Image manipulation tutorial back in the “How-to Guides”. (commit 465609174, contributed by Baptiste Nicolet).

    • Add support for JIT-freeting to the sunsky classes. (commit f07f26c5e).

Mitsuba 3.7.0

August 7, 2025

  • Upgrade Dr.Jit to version 1.1.0. The following list summarizes major new features added to Dr.Jit. See the Dr.Jit release notes for additional detail and various smaller features that are not listed here.

    The remainder lists Mitsuba-specific additions.

  • Function freezing. Using the previously mentioned @dr.freeze feature, it is now possible to freeze functions that call mi.render(). Rendering another view (e.g., from a different viewpoint or with a different material parameter) then merely launches the previously compiled kernels instead of tracing the rendering process again. This unlocks significant acceleration when repeatedly rendering complex scenes from Python (e.g., in optimization loops or real-time applications). Some related changes in Mitsuba were required to make this possible. (PRs #1477, #1602, #1642, contributed by Christian Döring).

  • AD integrators and moving geometry. All automatic differentiation integrators have been updated to correctly handle continuous derivative terms arising from moving geometry. In particular, the continuous (i.e., non-boundary) derivative of various integrators was missing partial derivative terms that could be required in certain geometry optimization applications. The updated integrators also run ~30% faster thanks to Shader Execution Reordering (SER). (PR #1680). We thank Markus Worchel, Ugo Pavo Finnendahl, and Marc Alexa for bringing this issue to our attention.

  • Gaussian splatting. Two new shape plugins support volumetric rendering applications based on 3D Gaussian splatting: ellipsoids is an anisotropic ellipsoid primitives using closed-form ray intersection, while ellipsoidsmesh uses a mesh-based representation. The volprim_rf_basic integrator documentation integrator renders emissive volumes based on them (PR #1464, contributed by Sebastien Speierer).

  • The new sunsky plugin implements Hosek-Wilkie models for the sun and sky, where sampling of the latter is based on Nick Vitsas and Konstantinos Vardis’ Truncated Gaussian Mixture Model. (PR #1473, #1461, #1491, contributed by Mattéo Santini).

  • Shader Execution Reordering (SER). The Scene.ray_intersect() and Scene.ray_intersect_preliminary() methods now accept a reorder parameter to trigger thread reordering on CUDA backends, which shuffles threads into coherent warps based on shape IDs. Performance improvements vary by scene complexity (ranging from 0.67x to 1.95x speedup). SER can be controlled globally via the scene’s allow_thread_reordering parameter or by disabling drjit.JitFlag.ShaderExecutionReordering. Most integrators have been updated to use SER by default. (PR #1623).

  • The performance of ray tracing kernels run through the CUDA/OptiX backend was significantly improved. Previously, several design decisions kept Mitsuba off the OptiX “fast path”, which is now fixed. (PRs #1561, #1563, #1568).

  • Mitsuba now targets the OptiX 8.0 ABI available on NVIDIA driver version 535 or newer. (PR #1480).

  • Bitmap textures now use half precision by default. (PR #1478.)

  • Improvements to the mitsuba.Shape interface. (PRs #1484, #1485).

  • The Mitsuba optimizers (e.g. Adam) were removed. They are now aliases to more sophisticated implementations in Dr.Jit. (Mitsuba PR #1569, Dr.Jit PR #345).

  • The Transform API became more relaxed—for example, Transform4f.scale() and Transform4f().scale() are now both equivalent ways of creating a transformation. This removes an API break introduced in Mitsuba version 3.6.0. (PR #1638).

  • Refactoring. The codebase underwent several major refactoring passes to remove technical debt:

    1. Removal of the legacy thread system and replacement with standard C++ constructs (PR #1622).

    2. Removal of the legacy object system and replacement with standard C++ constructs; rewrite of the mi.Properties and plugin loader implementations (PR #1630).

    3. Switched to a new parser and scene IR common to both XML and dictionary parsing; further work on mi.Properties (PRs #1669, #1676)

    4. Replaced Transform4f by specialized affine and perspective transformations. (PR #1679).

    5. Pass over the test suite to accelerate CI test runs (PR #1659)

    This is part of an ongoing effort to modernize and improve legacy Mitsuba code.

  • Added an API to easily read/write tensor files from Python and access them as Dr.Jit tensor instances in Python/C++ code (PR #1705).

  • The rawconstant texture plugin stores raw 1D/3D values without any color space conversion or spectral upsampling, useful when exact numerical values need to be preserved. (PR #1496, contributed by Merlin Nimier-David).

  • Various minor improvements and fixes. (PRs #1350, #1495, #1496, #1527, #1540, #1545, #1547, #1528, #1583, #1522, #1600, #1627, #1628, #1656, #1663, #1668, #1678, #1696, and #1702).

Mitsuba 3.6.4

February 4, 2025

  • Upgrade Dr.Jit to version 1.0.5.

  • Fix normalmap [1a4bea2]

  • Fallback mechanism for numerical issues in silhouette sampling [ce4af8d]

Mitsuba 3.6.3

January 29, 2025

  • Release was retracted

Mitsuba 3.6.2

January 16, 2025

  • Enable parallel scene loading by default in mitsuba CLI (regression) [338898d]

  • Improved bitmap construction in scalar variants [6af4d37]

Mitsuba 3.6.1

January 16, 2025

  • Improve robustness of parallel scene loading [8d48f58]

  • Fixes to mi.sample_tea_float [fd16fbe]

  • Support for complex numbers or quaternions in mi.ad.Adam optimizer [eff5bf6]

  • Improved error message when mi.load_dict fails [7db5401]

  • Add missing implementations for spot emitter (for AD) [9336491]

Mitsuba 3.6.0

November 25, 2024

This release comes with a major overhaul of some of the internal components of Mitsuba 3. Namely, the Python bindings are now created using nanobind and the just-in-time compiler Dr.Jit was updated to version 1.0.0.

These upgrades lead to the following:

  • Performance boost: 1.2x to 2x speedups depending on the JIT backend and scene size

  • Improved stubs: auto-completion and type-checking has been greatly improved

  • More variants on PyPI: thirteen variants are available in the pre-built wheels

Some breaking changes were made in this process. Please refer to the porting guide to get a comprehensive overview of these changes.

This release also includes a series of bug fixes, quality of life improvements and new features. Here’s a non-exhaustive list:

Mitsuba 3.5.2

June 5, 2024

Most likely the last release which uses pybind11.

  • OptiX scene clean-ups could segfault [03f5e13]

Mitsuba 3.5.1

June 5, 2024

  • Upgrade Dr.Jit to [v0.4.6]

  • More robust scene clean-up when using Embree [7bb672c]

  • Support for AOV fields in Python AD integrators [f3b427e]

  • Fix potential segfault during OptiX scene clean-up [0bcfc72]

  • Improve and fix Mesh PMF computations [ced7b22] .. [7d2951a]

  • Shape.parameters_grad_enabled now only applies to parameters that introduce visibility discontinuities [3013adb]

  • The measuredpolarized plugin is now supported in vectorized variants [68b3a5f]

  • Fix an issue where the constant plugin would not reuse kernels [deebe4c]

  • Minor changes to support Nvidia v555 drivers [19bf5a4]

  • Many numerical and performance improvements to the sdfgrid shape [455de40] .. [9e156bd]

Mitsuba 3.5.0

  • New projective sampling based integrators, see PR #997 for more details. Here’s a brief overview of some of the major or breaking changes:

    • New prb_projective and direct_projective integrators

    • New curve/shadow optimization tutorial

    • Removed reparameterizations

    • Can no longer differentiate instance, sdfgrid and Sensor’s positions

Mitsuba 3.4.1

December 11, 2023

  • Upgrade Dr.Jit to [v0.4.4]

    • Solved threading/concurrency issues which could break loading of large scenes or long running optimizations

  • Scene’s bounding box now gets updated on parameter changes [97d4b6a]

  • Python bindings for mi.lookup_ior [d598d79]

  • Fixes to mask BSDF when differentiated [ee87f1c]

  • Ray sampling is fixed when sample_border is used [c10b87b]

  • Rename OpenEXR shared library [9cc3bf4]

  • Handle phase function differentiation in prbvolpath [5f9eebd]

  • Fixes to linear retarder [8033a80]

  • Avoid copies to host when building 1D distributions [825f44f] .. [8f71fe9]

  • Fixes to linear retarder [8033a80]

  • Sensor’s prinicpal point is now exposed throught m̀i.traverse() [f59faa5]

  • Minor fixes to ptracer which could result in illegal memory accesses [3d902a4]

  • Other various minor bug fixes

Mitsuba 3.4.0

August 29, 2023

  • Upgrade Dr.Jit to v0.4.3

  • Add mi.variant_context(): a Python context manager for setting variants [96b219d]

  • Emitters may now define a sampling weight [9a5f4c0]

  • Fix bsplinecurve and linearcurve shading frames [3875f9a]

  • Add implementation of LargeSteps method for mesh optimizations (includes a new tutorial) [48e6428] .. [130ed55]

  • Support for spectral phase functions [c7d5c75]

  • Additional resource folders can now be specified in mi.load_dict() [66ea528]

  • BSDFs can expose their attributes through a generic eval_attribute method [cfc425a] .. [c345d70]

  • New sdfgrid shape: a signed distance field on a regular grid [272a5bf] .. [618da87]

  • Support for adjoint differentiation methods through the aov integrator [c9df8de] .. [bff5cf2]

  • Various fixes to prbvolpath [6d78f2e], [a946691] , [91b0b7e]

  • Curve shapes (bsplinecurve and linearcurve) always have back-face culling enabled [188b254] .. [01ea7ba]

  • Properties can now accept tensor objects, currenlty used in bitmap, sdfgrid and gridvolume [d030a3a]

  • New hair BSDF shading model [91fc8e6] .. [0b9b04a]

  • Improvements to the batch sensor (performance, documentation, bug fixes) [527ed22] .. [65e0444]

  • Many missing Python bindings were added

  • Other various minor bug fixes

Mitsuba 3.3.0

April 25, 2023

  • Upgrade Dr.Jit to v0.4.2

  • Emitters’ members are opaque (fixes long JIT compilation times) [df940c1]

  • Sensors members are opaque (fixes long JIT compilation times) [c864e08]

  • Fix cylinder’s normals [d9ea8e8]

  • Fix next event estimation (NEE) in volume integrators

  • mi.xml.dict_to_xml now supports volumes [15d63df]

  • Allow extending AdjointIntegrator in Python [15d63df]

  • mi.load_dict() is parallel (by default) [bb672ed]

  • Upsampling routines now support box filters [64e2ab1]

  • The Mesh.write_ply() function writes s, t rather than u, v fields [fe4e448]

  • All shapes can hold Texture attributes which can be evaluated [f6ec944]

  • Radiative backpropagation style integrators use less memory [c1a9b8f]

  • New bsplinecurve and linearcurve shapes [e4c847f] .. [79eb026]

Mitsuba 3.2.1

February 22, 2023

  • Upgrade Dr.Jit to v0.4.1

  • Film plugins can now have error-compensated accumulation in JIT modes [afeefed]

  • Fix and add missing Python bindings for Endpoint/Emitter/Sensor [8f03c7d]

  • Numerically robust sphere-ray intersections [7d46e10] .. [0b483bf]

  • Fix parallel scene loading with Python plugins [93bb99b]

  • Various minor bug fixes

Mitsuba 3.2.0

January 6, 2023

  • Upgrade Dr.Jit to v0.4.0

    • Various bug fixes

    • Stability improvements (race conditions, invalid code generation)

    • Removed 4 billion variable limit

  • Add missing Python bindings for Shape and ShapePtr [bdce950]

  • Fix Python bindings for Scene [4cd5585]

  • Fix bug which would break the AD graph in spectral variants [f3ac81b]

  • Parallel scene loading in JIT variants [48c14a7] .. [187da96]

  • Fix sampling of hg PhaseFunction [10d3514]

  • Fix envmap updating in JIT variants [7bf132f]

  • Expose PhaseFunction of Medium objects through mi.traverse() [cca5791]

Mitsuba 3.1.1

November 25, 2022

  • Fixed maximum limits for OptiX kernel launches [a8e6989]

Mitsuba 3.1.0

New features

  • Enable ray tracing against two different scenes in a single kernel [df79cb3]

  • Make ShapeGroup traversable and updatable [e0871aa]

  • Enable differentiation of to_world in instance [54d2d3a]

  • Enable differentiation of to_world in sphere, rectangle, disk and cylinder [b5d8c5d] .. [b5d8c]

  • Enable differentiation of to_world in perspective and thinlens [ea513f7] .. [ea513f]

  • Add BSDF::eval_diffuse_reflectance() to most BSDF plugins [59af884]

  • Add mi.OptixDenoiser class for simple denoising in Python [5529318] .. [55293]

  • envmap plugin can be constructed from mi.Bitmap object [9389c8d]

Other improvements

  • Major performance improvements in cuda_* variants with new version of Dr.Jit

  • Deprecated samples_per_pass parameter [8ba8528]

  • Fix rendering progress bar on Windows [d8db806]

  • obj file parsing performance improvements on Windows [28660f3]

  • Fix mi.luminance() for monochromatic modes [61b9516]

  • Add bindings for PluginManager.create_object() [4ebf700]

  • Fix SceneParameters.update() unnecessary hash computation [f57e741]

  • Fix numerical instabilities with box filter splatting [2d89762]

  • Improve math::bisect algorithm [7ca09a3]

  • Fix syntax highlighting in documentation and tutorials [5aa2716]

  • Fix Optimizer.set_learning_rate for int values [53143db]

  • Various minor improvements to the Python typing stub generation [b7ef349] .. [ad72a53]

  • Minor improvements to the documentation

  • Various other minor fixes

Mitsuba 3.0.2

September 13, 2022

  • Change behavior of <spectrum ..> and <rgb ..> tag at scene loading for better consistency between *_rgb and *_spectral variants [f883834]

  • Polarization fixes [2709889], [06c2960]

  • Add PyTorch/Mitsuba interoperability tutorial using dr.wrap_ad()

  • Fix DLL loading crash when working with Mitsuba and PyTorch in Python [59d7b35]

  • Fix crash when evaluating Mitsuba ray tracing kernel from another thread in cuda mode. [cd0846f]

  • Add stubs for Float, ScalarFloat and other builtin types [8249179]

  • Plugins regular and blackbody have renamed parameters: wavelength_min, wavelength_max (previously lambda_min, lambda_max) [9d3487c]

  • Dr.Jit Python stubs are generated during local builds [4302caa8]

  • Minor improvements to the documentation

  • Various other minor fixes

Mitsuba 3.0.1

July 27, 2022

  • Various minor fixes in documentation

  • Added experimental batch sensor plugin [0986152]

  • Fix LD sampler for JIT modes [98a8ecb]

  • Prevent rebuilding of kernels for each sensor in an optimization [152352f]

  • Fix direction convention in tabphase plugin [49e40ba]

  • Create TLS module lookup cache for new threads [6f62749]

Mitsuba 3.0.0

July 20, 2022

  • Initial release