NVIDIA/MDL-SDK 2026.0.0

MDL SDK 2026.0.0 (391700.996): 01 Jun 2026

Repository: NVIDIA/MDL-SDK

Tag: 2026.0.0

Published: 2026-06-16T12:00:19Z

Prerelease: no

Release notes: ABI compatible with the MDL SDK 2026.0.0 (391700.996) binary release (see https://developer.nvidia.com/mdl-sdk)

Added and Changed Features

• MDL 1.11 Language Specification
• Updated version to 1.11.
• Added enumeration type ::df::backscatter_modifier to modify backscattering behavior

of microfacet BSDFs.

• Added parameter uniform backscatter_modifier backscatter for the following BSDFs:
• specular_bsdf
• simple_glossy_bsdf
• microfacet_beckmann_smith_bsdf
• microfacet_ggx_smith_bsdf
• microfacet_beckmann_vcavities_bsdf
• microfacet_ggx_vcavities_bsdf
• fresnel_factor
• directional_factor
• measured_curve_factor
• measured_factor
• fresnel_layer
• color_fresnel_layer
• custom_curve_layer
• color_custom_curve_layer
• measured_curve_layer
• color_measured_curve_layer

• General
• The recommended vcpkg version has been updated to git ID 7853666. This update includes

GLEW 2.3.1 and various security fixes for dependencies.

• Improved performance of IMdl_module::is_valid().
• Added spectral rendering support. Refer to the MDL SDK Tutorial documentation

("Example for spectral rendering") for integration details.

• New spectral color type: tct_spectral_sample.
• New spectral shading state types: Shading_state_material_spectral and

Shading_state_material_spectral_with_derivs.

• BSDF/EDF data structures (Bsdf_sample_data, Bsdf_evaluate_data, etc.) are now

templated on Target_code_color_mode to switch between RGB and spectral layouts.

• New texture runtime functions for up-sampling from RGB to spectral.
• New SDK compile-time constant MDL_DF_SPECTRAL_SAMPLES to select the number of

spectral samples processed per call (default is 5). It can be overrided through the new CMake option MDL_DF_SPECTRAL_SAMPLES_OVERRIDE.

• New backend option libbsdf_enable_spectral enables spectral code generation on backends.
• Example runtimes and integrations for the native, HLSL, and GLSL backend.
• Spectral evaluation operates at the BSDF/EDF level only; all input data (colors,

textures, etc.) remain RGB, but the SDK provides built-in and custom means to upsample them to spectral samples per wavelength.

• Refer to the MDL SDK Tutorial documentation ("Example for spectral rendering") for

integration details.

• The new CMake option MDL_BUILD_SEPARATE_DEBUG_INFO allows generating separate debug

information in release builds.

• The API reference documentation can now also be built with newer Doxygen versions,

although the recommended version has been unchanged.

• The thread-safety guarantees for transactions and database elements have been improved.

See documentation on ITransaction for details.

• The performance of internal accesses to database elements has been improved.
• The unused interfaces Std_allocator and Default_allocator have been deprecated.

Still available if MI_NEURAYLIB_DEPRECATED_17_0 is defined.

• The support for MI_NEURAYLIB_DEPRECATED_15_0 has been removed.
• The documentation for the ::base and ::nvidia::core_definitions modules has been

converted to Markdown format.

• Improved handling of I/O errors and invalid input in the OpenImageIO and DDS plugins.
• Added the API component IExtension_api which allows to register custom IStruct and

IEnum declarations.

• Added support for Ninja as CMake generator on Windows.

• MDL Compiler and Backends
• Added backend option libbsdf_enable_spectral to enable spectral support.

When enabled, the BSDF data structures will use spectral sample types for IOR, BSDF, pdf, and albedo fields. The texture runtime was extended with spectral support functions, which can be left unimplemented (null pointers) if spectral mode is not used. In spectral mode, the native runtime expects Shading_state_material_spectral or Shading_state_material_spectral_with_derivs to be used, which contain a new field for the currently active wavelengths. Other backends may use alternative mechanisms to make the wavelengths available to the spectral support functions in the texture runtime.

• Improved HLSL/GLSL code generation.
• Added MDL_JIT_DISASM_FILE environment variable to dump native JIT disassembly to a

file for debugging.

• Changed alignment of texture results and matrices to 16-byte alignment.
• Added glsl_include_for_api_types GLSL backend option to emit an include directive of

the provided file name instead of the API types. This allows the use of custom API types with additional fields. If this option is used, the GL_GOOGLE_include_directive GLSL extension will be required.

• Handle integer division overflow gracefully in constant folding. A new warning is

issued: "integer overflow in expression (int)min -1 of type int results in ``"

• MDL Distiller and Baker
• Improved distilling of rough transparent materials for the rtx_distiller target.
• Added support for blending of bsdf() (as well as BSDFs converted to bsdf() like

measured_bsdf()) for the rtx_distiller target.

• Added support for emission mixing for the rtx_distiller target.

• MDL SDK examples
• The df_native, df_vulkan, and dxr examples now demonstrate the new MDL SDK

spectral rendering feature via the --spectral command-line option (default rendering remains RGB).

• Example df_native:
• Added support for evaluation of hair-BSDFs on an analytical cylinder.
• Example df_native and dxr:
• Gamma correction now clips values to avoid NaNs.
• Example dxr:
• Added command line option --load_plugin to load additional plugins like custom

distiller plugins.

• Added command-line option --show_camera. In the camera panel, it shows world-space

position and focus (same convention as --camera).

• MDL Core examples
• Clamp maximum path length to [2,100].
• Example codegen:
• Generate code also for volume.emission_intensity.
• Example df_cuda:
• Harmonized command-line options: -p is now the MDL path (i.e., --mdl_path),

--camera is now the camera parameter (previously -p), and --help has been added.

Fixed Bugs

• General
• Fixed detection of MaterialX for the vcpkg x64-windows triplet.
• Fixed a rare build error in parallel builds on Windows for projects that embed a

Windows resource file.

• Fixed sentinel value of IImage::get_uv_tile_id() (was 2^32-1 instead of 2^64-1).
• Fixed documentation...