RT Camp 11 Renderer

Transcript

1. Caribou 11 Renderer rtcamp11 https://sites.google.com/view/rtcamp11 kinankomoti @Kinakomoti2357
2. Caribou11Renderer • Vulkan/Slang implementation • Only compute pipeline(Ray Query) • Fur Rendering • Marschener model • Strand model
3. Caribou11Renderer • HD(1280x720) • 12 fps • 108 frame (9sec)
4. 真実
5. 私は真実に気づきました
6. Caribou(トナカイ) 一般的にはReindeer
7. Reindeer
8. Reindere •おや…?
9. Rendere •おや…?
10. Renderer •!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
11. Renderer is トナカイ
12. Renderer is トナカイ
13. •この真実を伝えなくてはいけない!!!!!
14. Caribou Renderer 11
15. Caribou Renderer 11
16. Why Fur Rendering
17. Why Fur Rendering • もふもふが好きだから…
18. Fur Reflectance Model • Marschener model [Marschner et al. 2003] • Energy Conservation [d’Eon et al. 2011] • Artist-friendly parametrization [Chiang et al. 2016] • Implementation Reference • 9.9 Scattering from Hair, PBRT 4th edition. • もふもふレンダリング入門, Ushio
19. Fur Reflectance Model • Strand model [Hostettler 2025] • Approximate Single Scattering in Fur • TTs, TRTs path • + feather, artist-friendly parameterization
20. Fur Reflectance Model • Combined Marschener + Strand • Fix transmittance • Probably…? Maybe…? Ok? • Color depended by view direction
21. Why Poison Reindeer
22. Why Poison Reindeer • パラメーター調整が難しい • 散乱係数1つ、吸収係数2つ • Roughness2つ • Colorからの変換は自明ではない • (その辺調査しきれなかった) • 派手な色の方が面白かった • 手動で適当に付けた Marschener + Strand Marschener
23. Scene Assets • Mesh data • Created by Blender, Substance • Fur data • Created by Houdini • Transport as text data
24. Fur Geometry • Use LSS(Linear swept sphere) • Generated by linearly varying the radius and position of a sphere • (maybe called by only Nvidia) • Feature • Easy management • Easy implementation • Free joint • Discrete • Duplicate geometry
25. Fur Geometry • If you have TRYPOPHOBIA, please close your eyes. • 集合体恐怖症の人は目をつぶっ てください
26. Fur Geometry • 8 LSS per fur fiber
27. Fur Data in Houdini • Export fur in Houdini • Use python node in TOP • Position • Radius(width) • Color
28. Fur Data in Renderer • Convert point to LSS • Raidus(start, end) • Position(start, end) • Color • ID(for rendering)
29. Fur Data in Renderer • Convert point to LSS • Raidus(start, end) • Position(start, end) • Color • ID(for rendering)
30. Library • glm • tinygltf • stb_image • nlohmann/json • fpng • png出力がstb_imageの10倍ぐらい早い
31. AI Coding • ChatGPT, Codex • Importor, Exportorの実装やバグチェックに使いました
32. AI Coding • 助かった点 • ヒューマンエラーのFix • 明確なErrorのFix • Thirdparty Loaderなどシンプルな実装 • 意外と論文の式と合ってるかみたいな チェックできたりする • ヒューマンエラーがかなり減った
33. AI Coding(余談) • LSSの導出時に解けなかった図形問題をChatGPTに渡してみた
34. AI Coding(余談) • 普通に正解された
35. AI Coding(余談) • 俺はAIの犬
36. 謝辞 • ushiostarfishさん 記事や実装で大変お世話になりました
37. Reference • [Kajiya and Kei. 1989] RENDERING FUR WITH THREE DIMENSIONAL TEXTURES • [Marschner et al. 2003] Light Scattering from Human Hair Fibers • [d’Eon et al. 2011] An Energy-Conserving Hair Reflectance Model • [Chiang et al. 2016] A Practical and Controllable Hair and Fur Model for Production Path Tracing • [Yan et al. 2017] An Efficient and Practical Near and Far Field Fur Reflectance Model • [Hostettler 2025] Strand: A Production Model for Shading Hair, Fur and Feathers • 9.9 Scattering from Hair, PBRT 4th edition. • もふもふレンダリング入門, Ushio. • Render Path-Traced Hair in Real Time with NVIDIA GeForce RTX 50 Series GPUs