XPU

General

• The stability of adaptive rendering with the GPU on complicated scenes with string lookups has been improved. RMAN-22085

Geometry

• Fixed crashes on the GPU that could occur when using the OSL printf(), warning(), or error() shadeops. RMAN-22085
• Fixed instability issues with XPU when using Solaris. RMAN-22151

Lighting

• Fixed a crash that could occur when using light filters with light linking. RMAN-22154
• Fixed an issue that could lead to fireflies in situations with stacked lights (such as a dome light behind another light source). RMAN-21969

Geometry

• Fixed an An issue unique to 26.0 that could cause crashes on certain non-manifold subdivision mesh surfaces has been fixed. RMAN-22051

Texturing

• XPU now automatically adjusts the texture and ptexture reserved cache allocation size to be the minimum of the requested texture memory limit option, and the actual size needed to store all the highest mipmap level texture tiles in the scene. In cases where there are very few textures in the scene and the requested texture memory limit has been set very high, this can be a substantial memory reduction.

Volumes

• XPU's performance on aggregate volumes when rendering with the GPU has been significantly improved. (CONFIRM WITH JFONG AND ETHANJ THAT THIS HAS BEEN BACKPATCHED. WE ALSO NEED TO TRACK THE RELEASE DATE FOR LEGAL PURPOSES.)

RIS

Volumes

• Added caching to OpenVDB, which improves memory and speed performance in cases where the same VDB grid is used many times. (XPU already has a memory-focused variant of this optimization.) RMAN-21922

Texturing

• The RixTexture::TextureDerivatives() call has been restored to its former functionality. (In R26.0 it returned RixTexture::InvalidFile for non-texture-atlas files.)

Lama

• The accuracy of an edgeTint lookup-table used by the LamaConductor bxdf in "Artistic" mode has been improved in both RIS and XPU. This can lead to slight look differences for that bxdf at grazing angles.

Blender

• Fixed a bug where the field of view was not correct when resizing windows in a viewport render, and no camera exists in the scene.

• Fixed bugs related to refreshing an OSL shader via the PxrOSL shading node.
• Fixed a bug that caused integrators to use the wrong settings during IPR.
• Fixed a bug that caused instances created via geometry nodes to have the wrong material attached.