Welcome to RenderMan 21.7!

This release introduces the following improvements, fixes, and miscellaneous changes.

New Features

• Compatible with the Katana 3.0 Beta Release
• Cryptomatte support is added. Find example workflows in the Maya and Katana documentation. Volumes are not yet supported and will be opaque.

Cryptomatte output in Nuke

• 'it' now has expanded exposure controls allowing better viewing of HDR images.
• Mesh lights now support the same shadow controls and shadow linking as the analytic lights.
• Improvements to light selection on scenes with many lights should improve render times.
• Performance improvements to volume rendering, especially very sparse volume fields and/or single scatter volumes.
• OpenEXR texture reads (.tex as EXR) are faster.
• Added more controls to texture patterns:
  • This includes:
    • PxrTexture
    • PxrProjectionLayer
    • PxrLayeredTexture
    • PxrMultiTexture
    • PxrNormalMap
    • PxrBump
  • Added 3 new parameters to texture patterns:
    • int mipBias: bias mip selection, negative numbers bias lower resolution while positive numbers bias to higher resolution textures.
    • float maxResolution: clamp mip selection, useful to prevent loading of higher resolution mipmap levels.
    • optimizeIndirect: sets to an inexpensive Box filter on indirect hits, except on PxrBump where the filter is fixed.
  • The user attributes, "int texturemipbias" and "float maxtextureresolution", will override these settings. 
• Improvements to Display Filters allow for easier construction of non-physical effects.

Miscellaneous Changes

• GPU Denoise requires CUDA 7.5 and compatible hardware.

• For refraction, extinction and ssAlbedo are unconnectable on PxrSurface

• Added support for baking with displacement
• Improved precision of PxrRamp inputs
• PxrPortalLight: now supersamples the input texture, leading to less potential pixelization on low resolution textures
• PxrSphereLight's intensityNearDist is now more correct/precise.
• Path Traced Subsurface options in PxrSurface now converge more quickly for high phase values
• Lighting Services: 
  • Minor changes to horizon culling of lights and clusters to the light selection algorithm
  • Additional code robustness for lights: Fixed crash in cases where mesh lights were instanced
• PxrPortalLights, added more protection against slightly negative dot products in the portal sample function.
• PxrMarschner lobe picking improvements, this reduces the variance, especially for high albedo hair

• Memory optimizations in KD tree representation of volumes

• Optimizations for volumes in the case of low density volumes
• Updates to remove subsurfaceZeroScatterAttenuation to make sure that PxrLayerSurface reflects the new approach in PxrSurface
• Prevent PxrOcclusion from calculating occlusion for infinite lights.
• Add new RixShadingContext::GetNearestHits method with excludeSubset parameter.

• Reduced memory usage when baking complex scenes with PxrBakePointCloud.

• PxrDisney "ClearCoat" lobe has been renamed "Clearcoat" for output to standard LPEs used by other shipped materials.

• Thread contention has been reduced when emitting many RiObjectInstances from multiple threads.

• Added new API calls that Display and Sample filters can use to perform image processing (e.g., for NPR) across bucket boundaries.

Bug Fixes

• Fixed a possible race condition when plugins in multiple threads access the same subdivision mesh via the RixSubdivisionSurfaceEvaluatio n interface.

• Fixed a light selection bug when a scene was made up of all infinite lights

• Fixed a possible crash when using Denoise on Windows.

• A crash caused by rendering alembic files with large number of points has been addressed.

• Fixed issue that 0% progress was reported after hours of rendering.
• Fixed a crash with PxrVCM and volumes
• Fixed bug causing occasional incorrect normals on displaced Loop subdivision surfaces.
• Avoid crashing if using the Bake Hider on an empty scene.
• A crash observed when enabling watertight dicing on degenerate subdivision faces has been fixed.

• Fixed a problem where PxrVolume applied to NURBs geometry sometimes created incorrect shadows.

• Fix problems when rendering the VLen, PWorld, and other geometric AOVs when using volumetric glass shaders.

• Fix an interaction between PxrPathTracer with Russian roulette enabled at depth 1 and PxrVolume with single scattering leading to incorrect alpha values.

• Handling of volumes with camera visibility 0 has been made significantly more robust when dealing with complex situations including overlapping volumes and scattering from surfaces inside the volume.

• A bug causing multiscattered volumes to evaluate non-varyingprimvar lookups for emission has been fixed.

• When the extrememotiondof hider option is enabled, frame number is now incorporated into DOF sampling, preventing "shower door" (constant sliding noise across the frame) artifacts on out-of-focus objects.

• Fixed an issue where autocrop would not work correctly in openexr displays

• Fixed bug causing potential for nan results from edge-on sampling of disk or rect lights when using emissionFocus.

• A bug that caused issues with clearcoat layering with PxrLayerSurface has been addressed.

• A bug that prevented dispScaleSpace from applying on the PxrDispTransform node has been fixed.

• Fixed an issue where the adaptive sampler would finish an image before exitat checkpoint was reached.

Known Limitations

RenderMan Pro Server

• Rendering an alembic file with any instances will only render the original geometry. The procedural does not call ObjectBegin/ObjectEnd or ObjectInstance so all instances are ignored.
• Full LPE support is only available with the PxrPathTracer and PxrVCM integrators.
• Cryptomatte
• Crop renders write the whole image with black padding. These will still be correctly aligned with the main render.
• Single-scatter volumes show as an opaque volume envelope. Multi-scatter volumes work correctly.
• Checkpointing is not currently supported.
• Light Filters in the PxrVCM integrator do not affect or shape photon emission.
• The Cone Angle parameter for lights is incorrect, it does not match the input angle, this will be fixed in a future version.
• The PxrAovLight does not work properly with PxrUPBP.
• Analytical lights placed inside volumes may yield artifacts when made visible to the camera. As a workaround, the light camera visibility should be turned off, and a geometry with a similar shape should be used (visible to the camera, invisible to transmission and indirect rays), with the proper emissive bxdf.
• Using the '.' character in the handle for an OSL shader could cause unpredictable results during re-rendering.
• Instances are not supported for baking.
• 3d baking: no direct bake-to-ptex support.
• PxrBakePointCloud cannot directly render ptex.
• No RixPTC/pointcloud API (so PxrBakePointCloud cannot read ptc files).
• Sample/Display filter plug-ins do not have access to lighting services for light dependent effects, e.g. lens flare.
• Adding new mesh light on existing geometry during IPR results in double geometry.
• Camera visibility changes are not respected during Live Rendering.
• For PxrUPBP, If the light source is inside a volume, that volume needs to be defined as Volume “box”, RiVolume
• For PxrUPBP, To get a volume caustic, the object casting the caustic needs to have higher intersectpriority than the volume.
• For PxrUPBP, Overlapping heterogeneous volumes are not working yet. (However, overlapping homogeneous volumes do work.) This will be resolved in the future.
• When attempting to access an array primvar, you must first check the size of the array primvar and allocate the appropriate space. Not doing so may lead to a crash.
• Points and curves cannot have mesh lights attached to them.
• Deformation motion blurred volumes don't currently work with densityFloatPrimVar or densityColorPrimVar. You will need to use a PxrPrimVar node connected to densityFloat and densityColor instead.