HtoA 22.214.171.124 introduces Arnold 126.96.36.199 and is a feature release bringing a brand new post-processing framework (imagers), support for nested dielectrics, much improved progressive and adaptive sampling, on-demand texture loading on GPU, integration improvements for Solaris, and Arnold-USD (4e5710fa).
Download Arnold for Houdini
Follow these installation instructions
New Windows system requirement
If you use the Extract contents only option to install HtoA, you must manually install the Microsoft Visual C++ 2015-2019 Redistributable.
The VCRedist install is in the HtoA redist folder. For example:
- Houdini, Houdini FX, Houdini Indie and Houdini Education
- Windows 7 or later, with the Visual Studio 2019 redistributable.
- Linux with at least glibc 2.12 and libstdc++ 3.4.13 (gcc 4.4.7). This is equivalent to RHEL/CentOS 6.
- OSX 10.11 to 10.15. Note that macOS 11 Big Sur is not certified.
- CPUs need to support the SSE4.1 instruction set.
- GPU rendering works on Windows and Linux only and requires an NVIDIA GPU of the Turing, Volta, Pascal, or Maxwell architecture. We recommend using the 455.38 or higher drivers on Linux and 457.09 (Quadro), 457.30 (GeForce), or higher on Windows. See Getting Started with Arnold GPU for more information.
- Optix™ denoiser requires an NVidia GPU with CUDA™ Compute Capability 5.0 and above.
We're introducing a brand new framework to apply post-processing effects such as color correction, vignetting, or tone mapping. A new type of post-processing nodes called imagers operate on pixels before the output driver. Imagers can be chained. The initial set of imagers consists of:
Imagers work both in batch and interactive contexts. While imager parameters can change interactively during rendering, adding a new imager currently requires the render to be restarted, so it's a good idea to add the ones you will need to adjust at the beginning of an interactive session. We are looking at removing this limitation in a subsequent release. (core#8368, core#9716, core#9723, core#9724, core#9867, core#9868, core#9869, core#9938).
Lens Effects (vignetting)
Nested dielectrics: Physically-correct reflection and refraction of rays in scenes with adjacent dielectrics, such as liquids in glass vessels, has been implemented by resolving overlapping, i.e. "nested", dielectrics via a priority system. This allows for more realistic renders of scenes such as glass containers with liquid contents and bubbles, correctly accounting for the change in the index of refraction as rays refract through the transparent media. The new dielectric_priority parameter on the standard_surface shader assigns a priority to the internal dielectric medium of the closed transparent object the shader is assigned to. These priorities specify that in an area of overlap of two transparent objects, only the highest priority dielectric medium exists (see the schematic glass of water below). The priority is simply a signed integer (default 0), which can be increased or decreased as needed to define the dielectric medium in the overlap areas. If priorities are made equal, then media are effectively blended in the overlap. The effect can be disabled globally with
options.dielectric_priorities(Nested Dielectrics in the Advanced tab of the render settings) in case you need to revert to the legacy mode, which does not correctly compute the refractions. (core#6023)
Standard setup of a glass of water with an ice cube, using the priority system. Rollover image to view the result with the global dielectric_priority: disabled (not physically correct).
Nested dielectrics examples
Improved progressive and adaptive sampling: Better sampling now results in much faster noise convergence, especially with adaptive sampling enabled. (core#9941)
Left: Arnold 188.8.131.52 - Right: Arnold 184.108.40.206 - Both images rendered using the same settings: adaptive_threshold = 0.015 (default)
- Improved performance on Windows: Arnold now runs on average 7-8% faster overall on Windows. (core#5481, core#9876, core#9975)
- Improved IPR interactivity: IPR interactivity on both CPU and GPU, especially when moving the camera in a scene with many nodes (thousands to millions of meshes, ginstances, lights, shaders, etc.), is improved. For instance, a scene with 24,433 ginstances and simple shading went from 8 fps to 14 fps on the CPU and about 3 fps to 20 fps on the GPU. (core#8662, core#9918, core#10027, core#10029)
- Improved performance in Toon on Windows: The contour_filter used for toon rendering should now be faster and scale better especially on Windows, with up to 3x speedups on AMD Threadripper 2 and up to 4x speedups on AMD Threadripper 3 CPUs. (core#7844)
- Toon AOV prefix : The
toonshader has a new optional
aov_prefixthat will be prepended to the toon AOVs' names. For instance, if
"toon_", the toon diffuse AOV will be written out to
"toon_diffuse". This can be used when you need to access both the toon AOVs and the core's LPE AOVs. (core#9823)
- Improved soft creases in adaptive subdivision: Normals for soft creases follow the geometry closer for low iterations. (core#9971)
All cube edges have sharpness 3 creases. The diagram shows the new (top) and old (bottom) normals for 1, 2, 3, and 4 iterations.
- AA seed now included in EXR metadata: The AA seed of a render is now also included in EXR metadata. (core#9895)
- Improved support for MaterialX: Material nodes are now supported, shader nodes and node graph outputs can be connected to material node inputs. Node definitions implemented as node graphs can contain both Arnold native shaders and MaterialX standard library shaders. This is useful to build reusable and portable material groups and definitions, for example by using standard_surface with MaterialX patterns. The environment variable
ARNOLD_MATERIALX_NODE_DEFINITIONScan now point to directories and load multiple node definitions (see here) (core#9204, core#9618, core#9926)
- Fix the ETA and elapsed time counters for IPR renders (htoa#1544)
- Add an AOVs section for the
- Create Advanced tab in Arnold ROP sample settings (htoa#1569)
- Add the Lock Sampling Pattern, replacing the Noise Seed on the Arnold ROP (htoa#1571)
- Add AOV light groups and menu to Solaris lights (htoa#1502)
- Support Solaris shader translation for H18.5 (htoa#1537, htoa#1573)
- Add portal mode for dome light LOP (#1536)
enable_adapative_samplingoption to the Solaris render settings LOP (htoa#1528)
AA_sample_clampproperties to Solaris render settings (htoa#1553)
- Update the default values of transmission weight and camera weight on the solaris Light LOPs (htoa#1557)
- Support the Arnold OSL inline shader VOP in Solaris (htoa#1560)
- Fix camera pivot when orbitting the camera in Houdini 18.5 (htoa#1566)
- Per face material assignments for the render delegate (usd#520)
OptiX cache location change: The Optix cache directory used to be of the form:
arnold-<ARNOLD_VERSION>_driver-<DRIVER_VERSION>. Now it is simply
arnold. This means the same cache will be used across driver and Arnold versions. Upgrading to a new version will still likely cause a lengthy JIT/cache pre-population, but it will reduce disk usage as old versions will not stay around-consuming disk space. (core#9239).
OptiX cache location change: The Optix cache directory used to be of the form:
Skipped node updates: In order to improve IPR interactivity, we skip the per-frame node update if we believe that node has not changed. If our internal heuristics for detecting node changes is wrong and so that Arnold will always run node_update on every render pass. At the moment, this should only be needed for nodes that access
options.dielectric_priorities to False.
add mode of the
mix_shader also added the transparency closures, which means that effects such as min pixel width would be double-counted, leading to objects disappearing. Now, we will add only non-transparency closures, while we pass through the max of the transparency closures. The old behavior can still be obtained by setting
add_transparency to true (core#9952).
node_update was supposed to be called, you can set the
force_update metadata on your node:
options.camera in their
node_update. If you do not have access to your shader's source code, you can globally disable this optimization by setting the
options.enable_fast_ipr to false (core#8662).
Skipped node updates: In order to improve IPR interactivity, we skip the per-frame node update if we believe that node has not changed. If our internal heuristics for detecting node changes is wrong and
so that Arnold will always run node_update on every render pass. At the moment, this should only be needed for nodes that access
- htoa#1572 Fix a crash seen when setting inline
htoa#1444 Catch exception when translating materials containing undefined
- core#5518 Handle interruptions properly during procedural expansion
- core#9949 mesh_light with constant black texture causes degenerate light tree case
- core#9971 Subdivs: soft creases normals different in adaptive and regular
- core#9978 Viewport API doesn't apply the correct matrix for nested procedurals
- core#10031 Only shader node connections should use node output type
- core#9361 [GPU] OptiX assert when updating textures
- core#10024 [GPU] Incorrect texture selection or error when invalidating the texture cache with GPU sparse textures
- core#10026 [GPU] Rare crash in OptiX denoiser
core#10040 [GPU] Always report minor version field of Nvidia driver as two digits
- core#10048 [GPU] Wrong progress reporting using adaptive
- usd#513 Viewport representation in points mode doesn't have the correct matrix
- usd#543 Visibility is not checked on the current frame
- usd#556 motion_start and motion_end is only set if the matrix of the prim is animated
- usd#565 Animated transforms not translated properly if set on parent XForms
- usd#569 Render delegate not picking up OSL shader parameters
- usd#570 USD procedural is not picking up OSL shader parameters
- usd#574 Incorrect display of curve widths in Solaris when changing curve basis
- usd#577 Point light should have zero radius
- usd#580 The Render Delegate's depth range is incorrect if USD is at least version 20.02