RTX Mega Geometry SDK Change Log

September 16, 2025 ยท View on GitHub

1.0.1

Improvements

  • Add smooth vertex normal support which allows for lower tessellation rates and includes memory profiler row for vertex normals
  • Filter out degenerate normals for backface culling to improve backface test and reduce triangle count

Debugging Improvements

  • Improve shader debug with stable cluster index output from path tracing shader
  • Add surface highlighting feature where path-tracer will blink highlight a selected debug surface
  • Add utilities to shader debug to force output

Bug Fixes

  • Fix regression in surface 1-ring culling caused by 1D thread-ordering change, which resulted in incorrect lanes doing work for unrelated waves
  • Fix crash when refreshing media list after changing json/obj filters with an asset already loaded

1.0.0

Vulkan Support

  • Requires Vulkan SDK 1.4.313 or greater which uses Cluster SPIRV intrinsics
  • Convert all bindless arrays to use ResourceDescriptorHeap via Vulkan's mutable descriptor extension
  • Fix validation warnings and Vulkan shutdown crashes

Minor Changes

  • Expose isolation level in the UI
  • Add smooth single crease sharpness, which prevents transition artifacts between single and multicrease edges. Only visible if the isolation level is lowered.
  • Improve Profiler "Frame" Tab, add average times in tool tip, expose motion vector pass time
  • Update to Streamline v2.8.0

Bug Fixes

  • Fix thread-ordering to be compliant with SM6.6 1D quad lane ordering.
  • Fix micro-triangle view toggle when in DLAA mode.
  • Fix cases where a surface resulted in over U16_MAX clusters
  • Fix tessellation for when there was per-material displacement scaling
  • Fix crash for some malformed OBJ files with '0' values for some indices.

0.9.2

Performance Improvements

Test Scene: amy_kitchenset.scene.json (default camera: 79M microtriangles) Hardware: RTX 5090 @ 4K Render Resolution (r572.83)

  • Compute Cluster tiling: 4.0ms -> 1.0ms (300% speedup)
    • Coalesced UAV writes for structs, unaligned members were causing UAV readbacks
    • Coalesce per wave atomics into a groupshared atomic to reduce pressure on global/UAV atomics by 4x
  • Fill clusters: 4.9ms to -> 1.0ms (390% speedup)
    • Fixed cases where the compiler was unable to unroll loops due to dynamic loop counts
    • Specialized shaders by subdivision surface type, with a special path for Pure BSpline surfaces. Prefetch all control points into shared memory to be used wave wide.

Minor Fixes

  • Fix SpecularHitT guide buffer to DLSS-RR to improve coherence of specular rays.

0.9.1

Stability

  • Fix crash on scenes with multiple subdivision mesh instances when the topology quality color mode was selected
  • Fix a crash if scene with audio is loaded and no audio devices are present.

Topology Quality

  • Add button in the Subdivision Evaluator tab to switch to topology quality view if issues are detected
  • Fix Subdivision Evaluator UI not resetting upon scene load.

UI

  • Application Window Size/Maximized/Fullscreen and Window state is now saved to and restored from imgui.ini. Delete imgui.ini to reset layout

Minor

  • Make initial VRAM check non-fatal but add warnings about performance degradation, memory budgets.
  • Made localToWorld transform use Matrix3x4 for consistency
  • Style clean-up
  • Update donut version

0.9.0

Initial beta release.