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  2. # Overview
  3. This repository includes a number of example scenes and
  4. data for use with the [pbrt-v3]( renderer,
  5. which corresponds to the system described in the third edition of
  6. _Physically Based Rendering_, by Matt Pharr, Wenzel Jakob, and Greg
  7. Humphreys. (See also the [pbrt website](
  8. We hope that this data will be useful to users of `pbrt`, developers making
  9. changes to the system, and researchers in rendering. To our knowledge, all
  10. of these scenes and data can be used fairly freely. Some data is licensed
  11. under a Creative Commons Attribution license; see details in
  12. Section [Scene Credits] of this document.
  13. # Data Sets
  14. In addition to example scenes, there is some useful data for use with the
  15. system.
  16. * [bsdfs/](bsdfs/): this directory includes a variety of bidirectional scattering
  17. distribution functions (BSDFs) for use with the `FourierMaterial`. See, for
  18. example, the [coffee-splash](coffee-splash) scene for use of such a BSDF in a scene.
  19. * New versions of BSDFs for use with `FourierMaterial` can be generated
  20. with [layerlab](
  21. * [lenses/](lenses/): lens description files for a handful of real-world lens
  22. systems, for use with the `RealisticCamera`. See the scenes
  23. [villa/villa-photons.pbrt](villa/villa-photons.pbrt) and
  24. [sanmiguel/f6-17.pbrt](sanmiguel/f6-17.pbrt) for examples of their use.
  25. * [spds/](spds/): measured spectral power distributions for a variety of standard
  26. illuminants, light sources, metals, and the squares of the Macbeth color
  27. checker.
  28. # Scenes
  29. A variety of scenes are available, ranging from simple ones that show off
  30. an individual feature of the system, to more interesting ones that
  31. demonstrate complex lighting effects in scenes with detailed geometry and
  32. realistic reflection models.
  33. Scene files for many of the rendered figures in the book are included here;
  34. for example, [dragon/f11-13.pbrt](dragon/f11-13.pbrt) corresponds to Figure
  35. 11.13 in the third edition of the book.
  36. ## Directory Organization
  37. We've tried to organize all of the scene directories in a consistent
  38. manner; each scene directory is self-contained, containing all of the
  39. geometry, textures, and additional data needed to render the scene.
  40. With a few exceptions, each `*.pbrt` file in a scene directory represents a
  41. separate variant of the scene to be rendered (possibly with different light
  42. source configurations, different camera positions, etc.) Some scenes have
  43. `geometry.pbrt`, `lights-*.pbrt` and `materials.pbrt` files that collect
  44. common geometry and material definitions across these variants. Thus, you
  45. should be able to just run `pbrt scene-name.pbrt` for any of the remaining
  46. `*.pbrt` files to render the corresponding scene.
  47. Complex triangle meshes and other complex geometry is stored in the
  48. `geometry/` directories and texture maps are all in the respective
  49. `textures/` directories. (Similarly, any SPDs, realistic camera lenses,
  50. or BSDF files are stored in corresponding sub-directories.)
  51. The [images/](images/) directory (which has a structure that parallels that
  52. of the scene directories) has EXR and PNG files corresponding to the final
  53. output from rendering each corresponding scene. All PNGs were generated
  54. using the `imgtool` program from the `pbrt-v3` distribution; many had a
  55. scale factor applied with the `--scale` command-line option, and a number
  56. include a bit of bloom to improve visual realism (via the `--bloomlevel`
  57. and related command-line options.)
  58. ## Overview of Scenes
  59. ![](images/bathroom/bathroom.png height="200px")
  60. [bathroom](bathroom): Modern bathroom with soft indirect lighting and
  61. depth of field.
  62. ![](images/breakfast/breakfast-lamps.png height="200px")
  63. [breakfast](breakfast): Indoor scene with chairs around a table. One
  64. variant has light streaming in through blinds from the side, while
  65. another is only illuminated by the lights above the table. (For the
  66. second variant, light transport through the glass light fixtures is a
  67. good challenge for many light transport algorithms.)
  68. ![](images/buddha-fractal/buddha-fractal.png height="200px")
  69. [buddha-fractal](buddha-fractal): Stanford Buddha model made out of Stanford Buddha
  70. models. 25,250 instances, each with 29,890 triangles, giving a total
  71. geometric complexity of over 750 million triangles.
  72. ![](images/bunny-fur/f3-15.png height="200px")
  73. [bunny-fur](bunny-fur): Stanford Bunny with fur growing out of it, modeled using the
  74. new curve shape added to `pbrt` in the third edition of the book. Over
  75. 1.5 million curves are used.
  76. ![](images/caustic-glass/f16-9c.png height="200px")
  77. [caustic-glass](caustic-glass): Caustic pattern projected through a realistic model of a
  78. glass.
  79. ![](images/cloud/f15-4c.png height="200px")
  80. [cloud](cloud): One scene with a bright white cloud, showing the effect of
  81. multiple scattering in participating media, and another, with the same
  82. volume density but with much more absorption, showing the difference
  83. between highly-scattering and highly-absorptive media.
  84. ![](images/coffee-splash/splash.png height="200px")
  85. [coffee-splash](coffee-splash): A splash of coffee in a cup with a spoon, showing a
  86. complex simulated BRDF for the cup and saucer, and scattering in
  87. participating media inside the splash.
  88. ![](images/crown/crown.png height="200px")
  89. [crown](crown): Detailed model of the Austrian Imperial Crown.
  90. ![](images/dragon/f9-3.png height="200px")
  91. [dragon](dragon): A scanned dragon model rendered with many different materials,
  92. showing off the visual differences between them.
  93. ![](images/ecosys/ecosys.png height="200px")
  94. [ecosys](ecosys): Complex outdoor scene with many plants and trees.
  95. [figures](figures): A variety of fairly simple scenes used for figures in the book.
  96. ![](images/ganesha/ganesha.png height="200px")
  97. [ganesha](ganesha): Very detailed scan of a small statue, illuminated by area
  98. light sources.
  99. ![](images/head/head.png height="200px")
  100. [head](head): Human head model with a realistic BSSRDF, showing the effect of
  101. subsurface scattering.
  102. ![](images/killeroos/killeroo-gold.png height="200px")
  103. [killeroos](killeroos): The classic "killeroo" model, in a variety of settings.
  104. ![view-0](images/landscape/view-0.png height="200px")
  105. ![view-1](images/landscape/view-1.png height="200px")
  106. ![view-2](images/landscape/view-2.png height="200px")
  107. ![view-3](images/landscape/view-3.png height="200px")
  108. [landscape](landscape): Very complex realistic outdoor landscape scene, featuring
  109. 23,241 unique plant models. Thanks to object instancing, the scene has a
  110. total geometric complexity of 3.1 billion triangles, even though only 24
  111. million triangles need to be stored in memory.
  112. ![](images/pbrt-book/book.png height="200px")
  113. [pbrt-book](pbrt-book): A realistic model of the second edition of the _Physically
  114. Based Rendering_ book.
  115. ![](images/sanmiguel/sanmiguel.png height="200px")
  116. [sanmiguel](sanmiguel): A complex model inspired by a hotel in San Miguel de
  117. Allende, Mexico.
  118. [simple](simple): A variety of relatively simple scenes.
  119. ![](images/sportscar/sportscar.png height="200px")
  120. [sportscar](sportscar): Sportscar model, in a variety of illumination settings,
  121. showing off the substantial differences in overall visual appearance that
  122. result.
  123. ![](images/sssdragon/dragon_10.png height="200px")
  124. [sssdragon](sssdragon): Dragon model rendered with subsurface scattering, showing
  125. the effect of changing the density of the scattering medium in the
  126. various scene description files.
  127. ![](images/structuresynth/arcsphere.png height="200px")
  128. [structuresynth](structuresynth): A few interesting procedural scenes scenes converted
  129. from [Structure Synth]( into
  130. `pbrt`'s format.
  131. ![](images/tt/tt.png height="200px")
  132. [tt](tt): Audi TT car model.
  133. ![](images/veach-bidir/bidir.png height="200px")
  134. [veach-bidir](veach-bidir): A version of a classic scene with a variety of complex
  135. types of light transport developed by Eric Veach to show the value of
  136. bidirectional path tracing.
  137. ![](images/veach-mis/f14-13-mi.png height="200px")
  138. [veach-mis](veach-mis): Another scene based on one by Eric Veach, this one showing
  139. off the benefit of multiple importance sampling when rendering surfaces
  140. of varying glossiness illuminated by light sources of various sizes.
  141. ![](images/villa/villa-daylight.png height="200px")
  142. [villa](villa): Modern indoor environment. The `villa-daylight.pbrt` version is
  143. particularly tricky to render, as all of the indoor lighting comes via
  144. specular paths from the outside through the windows.
  145. ![](images/vw-van/vw-van.png height="200px")
  146. [vw-van](vw-van): Volkswagen Van, illuminated by a HDR environment map.
  147. ![](images/volume-caustic/caustic.png height="200px")
  148. [volume-caustic](volume-caustic): A glass sphere in participating media, showing off a
  149. volumetric caustic--light being focused in the scattering medium after
  150. passing through the sphere.
  151. ![Whiteroom daytime](images/white-room/whiteroom-daytime.png height="200px")
  152. ![Whiteroom night](images/white-room/whiteroom-night.png height="200px")
  153. [white-room](white-room): Interior scene, with two illumination
  154. configurations. The daytime variant is primarily illuminated by light
  155. coming through the windows from the outdoors, while the nighttime version
  156. is illuminated by the two lights in the scene.
  157. ![](images/yeahright/yeahright.png height="200px")
  158. [yeahright](yeahright): An unusual and intricate form on a glossy plate.
  159. [wip](wip): This directory has a few scenes that aren't quite ready;
  160. renderings don't yet look great, parameters need tuning, etc. We'll try
  161. to get to this eventually, or if you're able to get them in good shape,
  162. please submit an update (see the following).
  163. # Converting Scenes to pbrt's Format
  164. Given an amazing scene in another 3D file format, there are a few
  165. options for converting it to be used in pbrt. (We're always happy to have
  166. help with improvements in this area!)
  167. ## Cinema 4D
  168. The `exporters/cinema4d` directory in the pbrt-v3 distribution provides an
  169. exporter from Cinema 4D. This exporter was developed to export the amazing
  170. "landscape" scene that is on the book's front cover from Cinema 4D, so thus
  171. should be up to date with respect to pbrt's material models and rendering
  172. settings. We have seen good results with using this exporter for other
  173. Cinema 4D scenes.
  174. ## Wavefront OBJ
  175. The pbrt-v3 distribution includes a converter from the Wavefront OBJ
  176. format, `obj2pbrt`, that is built when the rest of the system is compiled.
  177. To run it, provide the path to an OBJ file and a filename for a new pbrt
  178. file:
  179. ```bash
  180. $ obj2pbrt scene.obj scene.pbrt
  181. ```
  182. If there is an accompanying material description file (e.g. `scene.mtl`),
  183. the values in it will be roughly mapped to corresponding pbrt materials.
  184. You will likely need to manually edit and tune the materials in the
  185. generated pbrt file in order to achieve reasonably good-looking results.
  186. Note that OBJ files only describe scene geometry; they don't include camera
  187. specifications or descriptions of light sources. (Thus, the generated pbrt
  188. input file only includes shape and material specifications that you'll need
  189. to add inside the WorldBegin/WorldEnd block of a full pbrt input file.)
  190. Unless you have camera and light source information separately, you'll need
  191. to specify both on your own (see "General Tips" below for some ideas about
  192. how to do this.)
  193. ## Blender
  194. Many very nice scenes have been modeled in
  195. [Blender]( and are freely available. (See, for
  196. example, the [BlendSwap]( website for many
  197. scenes that can be used via a Creative Commons license.) Our experience has
  198. been that the best approach to export scenes from Blender is to use
  199. Blender's native OBJ export (available via the File/Export menu item) and
  200. then to use the obj2pbrt utility described above to convert to pbrt's
  201. format.
  202. Blender scene files may have texture maps for the scene included directly
  203. in their `.blend` file. Choose "File/External Data/Unpack into Files" in
  204. Blender to save those files independently on disk. (Note that if the
  205. textures aren't PNG or TGA format, you'll need to convert to one of those
  206. for pbrt to be able to use them.)
  207. We would have hoped that the Blender exporter for
  208. [LuxRender]( would have worked well for pbrt
  209. (LuxRender is originally based on pbrt and still has a similar input file
  210. format.) Unfortunately, our experience has been that exporting to OBJ and
  211. using obj2pbrt gives a better starting point for the scene
  212. materials. (Further, the LuxRender Blender exporter silently fails if there
  213. aren't any lights in the scene.) We suspect that using this exporter as a
  214. starting point for a new direct Blender to pbrt exporter might be a
  215. worthwhile approach.
  216. ## Old Exporters
  217. The pbrt-v2 distribution includes
  218. [exporters]( for 2010
  219. era 3DS Max (which was used for the model used for the cover image for the
  220. second edition of the book), Blender, Mathematica, and [Structure
  221. Synth]( All of these are very much
  222. out of date, both due to changes over the past six years in in the systems
  223. they exported from as well as changes in pbrt. Some of these may be useful
  224. for developing updated exporters for the corresponding systems for pbrt-v3.
  225. ## General Tips
  226. A scene exported using one of the above exporters is certain to not
  227. immediately render beautifully as is. Here are some suggestions for how to
  228. take an initial export and turn it into something that looks great.
  229. First, you may find it useful to run
  230. ```bash
  231. $ pbrt --toply scene.pbrt > newscene.pbrt
  232. ```
  233. This will convert triangle meshes into more compact binary PLY files,
  234. giving you a much smaller pbrt scene file to edit.
  235. Next, if the exporter doesn't include camera information, the first thing
  236. to do is to find a good view. The "environment" camera (which renders an
  237. image in all directions) can be useful for finding a good initial position
  238. for the camera. Keep rendering images and adjusting the camera position to
  239. taste. (For efficiency, use as few pixel samples as you can tolerate and
  240. learn to squint and interpret noisy renderings!) Then, you can use the
  241. origin you've chosen as the basis for specifying a `LookAt` transformation
  242. for a more conventional camera model.
  243. While placing the camera, it can be helpful to have a point light source at
  244. the camera's position. Adding the following light source to your scene file
  245. does this in a way that ensures that the light moves appropriately to
  246. wherever the camera has been placed.
  247. ```
  248. AttributeBegin
  249. CoordSysTransform "camera"
  250. LightSource "point" "color I" [10 10 10]
  251. AttributeEnd
  252. ```
  253. Once the camera is placed, we have found that it's next useful to set up
  254. approximate light sources. For outdoor scenes, a good HDR environment map
  255. is often all that is needed for lighting. For indoor scenes, you may want a
  256. combination of an environment map for the outside and point and/or area
  257. light sources for interior lights. You may find it useful to examine the
  258. scene in the modeling system that it came from to determine which geometry
  259. corresponds to area light sources and to try adding `AreaLightSource`
  260. properties to those. (Note that in pbrt, area light sources only emit
  261. lights on the side that the surface normal points; you may need a
  262. `ReverseOrientation` directive to make the light come out in the right
  263. direction.
  264. Given good lighting, the next step is to tune the materials. It can be
  265. helpful to pick a material and set it to an extreme value (such as a
  266. "matte" material that is pure red) and render the scene; this quickly shows
  267. which geometric models have that material associated with it. As you do
  268. this, watch for objects that are missing texture maps and re-add
  269. them. (The good news is that such objects generally do have correct texture
  270. coordinates with them.
  271. # Submitting Updates
  272. We'd love to increase the scope (and quality) of scenes available for use
  273. with `pbrt`. If you have a nice scene in `pbrt`'s format that you'd like to
  274. have included in this distribution, or if you have improvements to the
  275. current set of scenes, we'd love to have them!
  276. Unfortunately, it's not possible to host large binary distributions on
  277. github, so it's a little more involved than sending a pull request. There
  278. are a few options for submitting updates.
  279. * For changes small enough to be sent via email, you can use
  280. `git format-patch` to make a patch that we can apply and push to the
  281. repository. (Send the patch to
  282. * For larger changes, consider the `git bundle` command to generate a
  283. binary representation of the changes. Post the resulting file online
  284. somewhere that we can access it, send us a pointer (again,
  285., and we'll merge it.
  286. * Finally, if you're not comfortable enough with git for those options,
  287. feel free to create a zip or tar file with a new scene and send us a
  288. pointer to it; we can take it from there.
  289. # Scene Credits
  290. * bathroom: Thanks to "nacimus", CC-BY license. Downloaded from
  292. * breakfast: Thanks to "Wig42", CC-BY license. Downloaded from
  294. * buddha-fractal: thanks for Guillermo M. Leal Llaguno for this fun variant
  295. of the Stanford Buddha model. (Buddha model courtesy [Stanford Computer
  296. Graphics Laboratory](
  297. * bunny-fur: Bunny model courtesy [Stanford Computer Graphics
  298. Laboratory]( Environment map
  299. via, thanks to Bernhard Vogl.
  300. * caustic-glass: Thanks to Simon Wendsche ( for
  301. the model.
  302. * cloud: Smoke dataset courtesy Duc Nguyen and Ron Fedkiw. Skylight
  303. environment map courtesy Nolan Goodnight.
  304. * coffee-splash: Scene thanks to "guismo"; CC-Attribution license.
  305. Downloaded from Environment map
  306. via, thanks to Bernhard Vogl.
  307. * crown: This amazing model was created by Martin Lubich
  308. (
  309. * dragon: Dragon model courtesy Christian Schüller. Environment map via
  310., thanks to Bernhard Vogl.
  311. * ecosys: Scene from Deussen et al., [Realistic modeling and rendering of
  312. plant ecosystems](
  313. * ganesha: Model scanned by Wenzel Jakob.
  314. * head: Model thanks to Infinite Realities, Inc., CC-Attribution license.
  315. Environment map thanks to [USC-ICT light probe image gallery](
  316. * killeroos: Thanks to [headus]( for the
  317. model.
  318. * landscape: Many thanks to Jan-Walter Schliep, Burak Kahraman, and Timm
  319. Dapper from [Laubwerk]( for this amazing scene.
  320. * pbrt-book: Thanks to Karl Li (yiningkarlli@) for this fun model.
  321. * sanmiguel: Thanks to Guillermo M. Leal Llaguno for this excellent scene.
  322. * sportscar: Excellent model and pbrt conversion courtesy of Yasutoshi
  323. Mori (@MirageYM); CC-BY license. Skylight environment maps courtesy Nolan
  324. Goodnight.
  325. * sssdragon: Dragon model courtesy [Stanford Computer Graphics
  326. Laboratory]( Environment map
  327. via, thanks to Bernhard Vogl.
  328. * structuresynth: Environment map thanks to [USC-ICT light probe image gallery](
  329. * tt: Thanks for Marko Dabrovic and Mihovil Odak for the car model.
  330. Environment map thanks to [USC-ICT light probe image gallery](
  331. * villa: Many thanks to Florent Boyer for this scene. Skylight environment
  332. map courtesy Nolan Goodnight.
  333. * vw-van: Model courtesy of
  334. [Greyscalegorilla](,
  335. exported from Cinema4D using the [Cinema4D pbrt
  336. exporter](
  337. * white-room: Scene thanks to Jay Hardy, CC-Attribution
  338. license. Downloaded from
  339. * yeahright: "Interesting" shape generated by Keenan Crane
  340. ( Environment
  341. map thanks to [USC-ICT light probe image
  342. gallery](
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