C4DtoA 4.0.0 uses Arnold 7.0.0.0 and is a major feature release adding ACEScg as the default rendering color space, Intel®'s Open Image Denoise, better denoising quality overall, important scalability improvements on GPU, and better performance and interactivity. This major release also introduces support to the Cinema 4D Node Material and Node Editor (still in beta), important changes in the Arnold API, such as the ability to render several scenes within the same process, and shaders now supporting multiple outputs. Support for Cinema 4D S22 is dropped.
Arnold shaders in the Cinema 4D Node Material (BETA): Arnold shaders are now available in the native Node Material within the Arnold node space in Cinema 4D R23 and above. The node graph can be edited via the native Node Editor. The feature is in beta state, see the known limitations below (C4DTOA-1940).
OSL shaders from a custom folder are not listed if the plugin path is defined in the scene. It has to be defined via the ARNOLD_PLUGIN_PATH environment variable before starting Cinema 4D.
Material stacking is not supported.
No python-support yet (other than the native support).
Viewport preview is not fully supported.
No shader preview if the shader has multiple outputs.
No custom material preview scenes are supported.
No custom Arnold-specific shortcuts.
No custom Arnold-specific editor functionality.
No custom Arnold-specific menu categories in Cinema 4D R23 (shaders are listed under Uncategorized).
Connecting shaders to non-linkable parameters does not show an error in Cinema 4D R23 and S24.
Default material system in Preferences: New option is added to the Preference window, which controls whether the new Node Material (still in beta) or the old Arnold Material is created from the menus. (C4DTOA-2513)
Reference shader in the Node Material: Reference shader is ported to the Node Material, which can reference another Node Material or an old Arnold Material. (C4DTOA-2401)
ACEScg as the default render color space: Default render color space is now changed to the industry standard Academy Color Encoding System (ACES) via an OCIO v2 config shipped with Arnold. This change does not affect existing scenes which use the builtin (legacy) color manager (linear color space with sRGB primaries). (C4DTOA-2503)
Bake texture into Picture Viewer output: New option is added to the render settings to bake the view color transform into the output saved in the Picture Viewer. This is needed to compensate for the built-in Cinema 4D color transform. Enable this option when saving to an 8-bit integer image (e.g. JPEG, PNG). Disable the option when saving to a 32-bit float image (e.g. EXR). This does not affect Arnold Drivers, only save from the Picture Viewer (including Commandline and Team Render). (C4DTOA-2540)
Color space of Arnold Sky and Arnold Light color texture: Color space of a texture linked to the Arnold Sky or Arnold Light color (e.g. HDRI map) can be properly defined. In case of a 32-bit texture (e.g. .hdr) it defaults to linear color space with sRGB primaries (linear sRGB). (C4DTOA-2531)
Color space aliases: New options are available when selecting color space of a texture: sRGB, linear sRGB, raw. These aliases resolve to the actual color spaces defined by the active color manager and allow smooth switching between color managers (e.g. legacy <-> default ACES) and managing material assets created with a specific color manager. (C4DTOA-2480)
Set default color manager in Preferences: The default color manager can be overridden in the Preferences window. This is the color manager which is created in new scenes or new render settings by default. This can be useful when someone wants to use a custom OCIO config instead of the built-in one, or a custom color manager. Normally the default ACES config is fine and this option is not set. (C4DTOA-2471)
LUT settings are removed from the IPR window: LUT settings are removed from the Display tab of the IPR window, use the tonemap imager instead. LUTs now apply to the Picture Viewer as well, not just the IPR. (C4DTOA-2386)
GPU Enhancements
USD Enhancements
Incompatible Changes
Bug Fixes
C4DTOA-2555 HDR sky texture is displayed dark in the viewport
API
The C4DtoA API has been modified which requires third-parties to recompile their C4DtoA extensions.