1 / 53

RenderMan (Introduction)

RenderMan (Introduction). Objective. Understanding of graphics algorithms Rendering pipeline Understanding of Technical Director’s role Learning the Shading Language Notion of Shader. Lecture Outline. Computer graphical Image Synthesis RenderMan – A Brief History Using BMRT The RIB File

arion
Télécharger la présentation

RenderMan (Introduction)

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. RenderMan(Introduction)

  2. Objective • Understanding of graphics algorithms • Rendering pipeline • Understanding of Technical Director’s role • Learning the Shading Language • Notion of Shader

  3. Lecture Outline • Computer graphical Image Synthesis • RenderMan – A Brief History • Using BMRT • The RIB File • The Shading Language • Writing a Shader

  4. Computer graphical Image Synthesis : Image Synthesis Three routes to image synthesis

  5. Computer graphical Image Synthesis : Rendering A renderer being fed a scene description

  6. Computer graphical Image Synthesis : Rendering RenderMan converts RIB inputs into images RIB: Renderman Interface Bytestream

  7. Computer graphical Image Synthesis : Rendering Object Space Clipping Culling World Space Final Result Camera View Stages in a classical rendering pipeline

  8. The RenderMan History • Proposed by Pixar in 1989 • Its design is based on • Lucasfilm’s REYES (Renders Everything You Ever Saw) in 1981 (Pixar is originally the computer division of Lucasfilm) • Robert Cook’s Shade Trees [COOK84] • Since then RenderMan is referred as the industry standard of high-quality graphics production

  9. What is RenderMan? • An open specification – anybody can implement the standard • Pixar RenderMan, BMRT, RenderDotC • A scenefile description for 3D rendering like PostScript is for 2D • Programmable shading language • C Programming Interface • Can be a standalone program or called from RIB.

  10. What is RenderMan • Separation of Modeling and Rendering • RenderMan serves as the interface. • Scene = Shape + Shading • Two “languages” • Geometry(Shape) - set of C subroutines • Shading - a C-like language • Geometry code can be run directly, or output to RIB file • Shading code is compiled to byte-code • The power of RenderMan is in the shading part

  11. Movies containing RenderMan-generated imagery

  12. RenderMan Interface

  13. RenderMan Interface • RenderMan Interface Bytestream (RIB): Geometry • The scene description language (.rib) can be created by a C program, generated by the modeler, or typed manually • The scene description file defined the geometry and some rendering parameters • Shading Language (SL): Shading • A skillful programmer develops the shader (.sl), a C-like program, to control how a surface is shaded. It is then complied to intermediate code (.slo) • The intermediate shader code is interpreted to control the shading process • The .rib and .slo are fed to the renderer for rendering

  14. RenderMan Interface RIB as an interface between modelers and renderers

  15. RIB File Structure

  16. Rendering program • RenderMan compliant renderer • Pixar’s Photorealistic RenderMan (PRMan) • Exluna’s BMRT, Entropy • ART’s RenderDrive

  17. BMRT (Blue Moon Rendering Toolkit) • A free implementation of the RenderMan standard • A public-domain implementation of Pixar Photorealistic RenderMan (PRMan). • Three main components: • Rendrib: the renderer • Rgl: quick rendering for preview • Slc: shading language compiler • Download • Pixar Renderman BMRT Render 2.6.rar

  18. How to Install BMRT • Unpack the BMRT Distribution • Choose a directory into which BMRT will be installed (e.g. “c:\BMRT2.6”) • Set BMRT Environment Variables • Variable: PATH Value:[…];C:\BMRT2.6\bin (i.e., add C:\BMRT2.6\bin to the end of the current PATH value.)  • Variable: BMRTHOMEValue: C:\BMRT2.6\  • Variable: SHADERS  Value: C:\BMRT2.6\shaders

  19. How to Install BMRT • Testing BMRT • Command  cmd • C:\> cd BMRT2.6\examples  C:\BMRT2.6\examples\> • Test rgl • C:\BMRT2.6\examples\> c:\BMRT2.6\bin\rgl teapots.rib hit the esc key or q to close the window after it finishes rendering. • C:\BMRT2.6\examples\> c:\BMRT2.6\bin\rgl limbo.rib • Test slc • C:\BMRT2.6\shaders\> c:\BMRT2.6\bin\slc funkyglass.sl • C:\BMRT2.6\shaders\> c:\BMRT2.6\bin\slc screen_aa.sl • C:\BMRT2.6\shaders\> c:\BMRT2.6\bin\slc screen.sl • Test rendrib • C:\BMRT2.6\examples\> c:\BMRT2.6\bin\rendrib -d 16 shadtest.rib • The -d option to rendrib will display the results directly to the screen • press the w key while over the window to write out a TIFF file • the esc key or q will quit and close the window • Testiv • C:\BMRT2.6\examples\> c:\BMRT2.6\bin\iv balls1.tif

  20. Using BMRT • Rendrib – the command line renderer • Rendrib [flags] <filename> • -d • Forces display to screen • Put a number afterward and it will render in multiple passes • -v – verbose. Tells you more about what is happening while you render. • -stats – displays some statistics after rendering about CPU usage, etc. • Slc – the shading language compiler • Slc [flags] <filename> • -dso compile to machine code • -o name output to specified name

  21. A Simple Scene #min.rib - a minimal scene Display "min.tiff" "file" "rgb" Projection "perspective" WorldBegin Translate 0 0 2 Sphere 1 -1 1 360 WorldEnd • Making RIB • # : comment (주석) • Display • Create a file “min.tiff” • Color information “rgb” • “file”  write to “file” • “framebuffer”  on the screen • Projection • “perspective” projection • WorldBegin / WorldEnd • WorldBegin  prepare to draw • WorldEnd  the scene is finished • Transformation / Modeling • Translation  z 축으로 2만큼 이동 • Sphere radius: 1, zmin: -1, zmax: 1, theta: 360

  22. Transformation # beginend.rib Display "beginend.tiff" "file" "rgb" Projection "perspective" WorldBegin # move everything back 2 units Translate 0 0 2 TransformBegin # Everything that follows is one unit left Translate -1 0 0 Sphere 1 -1 1 360 TransformEnd TransformBegin # Everything that follows is one unit right Translate 1 0 0 Sphere 1 -1 1 360 TransformEnd WorldEnd • Transformation • Translate x y z • Scale x y z • Rotate angle x y z • TransformBegin • TransformEnd

  23. Color # Display "beginend.tiff" "file" "rgb" Projection "perspective" WorldBegin Translate 0 0 2 Color [ 1 0 0 ] AttributeBegin Translate -1 0 0 Color [ 1 1 0 ] Sphere 1 -1 1 360 AttributeEnd #This resets the colour back to red AttributeBegin Translate 1 0 0 Sphere 1 -1 1 360 AttributeEnd WorldEnd • Color Color [ red green blue ]  0~1 • AttributeBegin : 속성 설정 시작 • AttributeEnd : 속성 설정 종료

  24. Color • Opacity Opacity [ red green blue ] 0: Transparency (투명) 1: Opaque (불투명) Display "opacity.tiff" "file" "rgb" Projection "perspective" #PixelSamples 3 3 WorldBegin #move everything back 2 units Translate 0 0 2 Color [ 1 0 0 ] AttributeBegin         Translate -0.25 0 0         Color [ 0 1 0 ]         Opacity [ 0.5 0.5 0.5 ]         Sphere 1 -1 1 360 AttributeEnd AttributeBegin         Translate 0.25 0 0 #        Opacity [ 0.3 0.3 0.3 ]         Sphere 1 -1 1 360 AttributeEnd WorldEnd

  25. Camera Setup • Camera • Format : 이미지 크기 • “fov” • Field of View # fov.rib Display "fov.tiff" "file" "rgb" Format 640 480 1.0 Projection "perspective" "fov" [ 25 ] # Projection "perspective" "fov" [ 90 ] Translate 0 0 10 WorldBegin         Sphere 2 -2 2 360 WorldEnd

  26. Blocks • WorldBegin, WorldEnd • FrameBegin, FrameEnd frameno • AttributeBegin, AttributeEnd • TransformBegin, TransformEnd • Stacking must always be balanced • AttributeBegin • TransformBegin • AttributeEnd • TransformEnd is not legal

  27. Simple Surface • Parametric Quadrics • Sphere • Cone • Cylinder • Disk • Hyperboloid • Paraboloid • Torus

  28. Simple Surface • Sphere Sphere <radius> <zmin> <zmax> <sweep_angle> # sweep.rib Display “sweep.tiff" “file" "rgb" Projection "perspective" WorldBegin Translate 0 0 4 Sphere 2 -2 2 270 WorldEnd

  29. Simple Surface • Cylinder Cylinder <radius> <zmin> <zmax> <sweep_angle> # Cylin.rib Display "Cylin.tiff" "file" "rgb" Projection "perspective" WorldBegin Translate 0 0 7 Rotate 90 1 0 0 Cylinder 2 -3 3 270 WorldEnd

  30. Simple Surface • Cone Cone <height> <radius> <sweep_angle> # Cone.rib Display "Cone.tiff" "file" "rgb" Projection "perspective" WorldBegin Translate 0 -2.5 7 Rotate -90 1 0 0 Cone 5 2 90 WorldEnd

  31. Simple Surface • Paraboloid Paraboloid <radius_at_zmax> <zmin> <zmax> <sweep_angle> # Para.rib Display "Para.tiff" "file" "rgb" Projection "perspective" WorldBegin Translate 0 -0.5 1.5 Rotate 90 0 1 0 Rotate -90 1 0 0 Paraboloid 0.6 0.0 1.0 360 # Paraboloid 1.0 0.25 0.9 330 WorldEnd

  32. Simple Surface • Hyperboloid Hyperboloid <x1> <y1> <z1> <x2> <y2> <z2> <sweep_angle> # Hyper.rib Display "Hyper.tiff" "file" "rgb" Projection "perspective" WorldBegin Translate 0 0 2.0 Rotate 90 0 1 0 Rotate -90 1 0 0 Hyperboloid 0.15 -0.8 -0.5 0.25 0.25 0.6 360 # Hyperboloid 0.4 1.0 -0.5 0.5 0.5 1.0 300 WorldEnd

  33. Simple Surface • Torus Torus <major_radius> <minor_radius> <start_angle> <end_angle> <sweep_angle> # Torus.rib Display "Torus.tiff" "file" "rgb" Projection "perspective" WorldBegin Translate 0 0 1.5 # Rotate -120 1 0 0 Torus 0.5 0.25 0 360 360 # Torus 0.6 0.1 0 360 120 # Torus 0.55 0.35 0 100 360 WorldEnd

  34. Simple Surface • Disk Disk <height_along_z> <radius> <sweep_angle> # Disk.rib Display "Disk.tiff" "file" "rgb" Projection "perspective" WorldBegin Translate 0 0 1.0 Disk 0 0.5 360 # Disk 0 0.7 270 WorldEnd

  35. Convex Concave Simple Surface • Polygon Polygon "P" [...... points..] GeneralPolygon [ poly_vert# vert_hole1# vert_hole2# .....] “P” [....points...] # GPolygon.rib Display "GPolygon.tiff" "file" "rgb" Projection "perspective" WorldBegin Translate -0.5 -0.5 1.0 GeneralPolygon [4 3] "P" [ 0 0 0 1 0 0 1 1 0 0 1 0 0.1 0.1 0 0.9 0.1 0 0.5 0.9 0 ] WorldEnd # Polygon.rib Display "Polygon.tiff" "file" "rgb" Projection "perspective" WorldBegin Translate -0.5 -0.5 1.0 Polygon "P" [ 0 0 0 1 0 0 1 1 0 0 1 0 ] WorldEnd

  36. Convex Concave Simple Surface • PointsPolygon PointsPolygon [ face1_vert# face2_vert# …. ] [ face1_index1 face1_index2 …. face2_index1 face2_index2 …. …. ] "P" [...... points..] PointsGeneralPolygon [2 (face, hole) 1 (no hole) ….] [ face1_vert# (face) face1_vert# (hole) face2_vert# (face) …. ] [ face1_index1 face1_index2 …. face2_index1 face2_index2 …. …. ] "P" [...... points..] # PPolygon.rib Display "PPolygon.tiff" "file" "rgb" Projection "perspective" WorldBegin Translate 0 0 1.5 Rotate -10 1 0 0 PointsPolygons [3 3 3 3] # 4 faces, each with 3 verts, 12 total [2 1 0 1 0 3 2 0 3 2 1 3] # indices of the 12 verts # following is the vertex array with (x,y,z) pt "P" [ 0.664 0.000 -0.469 0.000 -0.664 0.469 0.000 0.664 0.469 -0.664 0.000 -0.469 ] WorldEnd

  37. Patches # patch.rib Display “patch.tiff" "file" "rgb" Projection "perspective“ “fov” [20] Translate -0.5 -0.5 3 WorldBegin LightSource "ambientlight" 1 "intensity" [ 0.1] LightSource "pointlight" 2 "from" [-2 2 -2] "intensity" [ 7 ] Color [ 1 0 0 ] Surface "plastic" Patch "bilinear" "P" [ 0 0 0 1 0 0 0 1 0 1 1 0] WorldEnd • Patches • Provide curved surface Patch “type” “P” [...... points..] • Type : bilinear , bicubic Ordering of Points

  38. Patches • Bilinear #curved.rib Display "curved.tiff" "file" "rgb" Projection "perspective" "fov" [ 20 ] Translate -0.5 -0.5 4 WorldBegin LightSource "ambientlight" 1 "intensity" [ 0.1] LightSource "pointlight" 2 "from" [-2 2 -2] "intensity" [ 7 ] Color [ 1 0 0 ] Surface "plastic" Patch "bilinear" "P" [0 0 0 1 0 0 0.4 1 1 #MOVED BACK 0.6 1 -1] #MOVED FORWARDS WorldEnd

  39. Patches • Bicubic #cubic.rib Display "cubic.tiff" "file" "rgb" Projection "perspective" "fov" [ 30 ] Translate -0.5 -0.5 3 WorldBegin LightSource "ambientlight" 1 "intensity" [ 0.1] LightSource "pointlight" 2 "from" [-2 2 -2] "intensity" [ 10 ] Color [ 1 0 0 ] Surface "plastic" Rotate 40 1 0 0 Patch "bicubic" "P" [ 0 0 0 0.4 0 0 0.6 0 0 1 0 0 0 0.4 0 0.4 0.4 3 0.6 0.4 -3 1 0.4 0 0 0.6 0 0.4 0.6 -3 0.6 0.6 3 1 0.6 0 0 1 0 0.4 1 0 0.6 1 0 1 1 0] WorldEnd

  40. Lighting • Lighting • Point light • Distant light • Spot light • Ambient light

  41. Point light intensity [7] intensity [14] • Point light • Pointlight creates a light that shines equally in all direction • LightSource • “pointlight” : 점광원 • “from” : 광원의 위치 • “intensity” : 빛의 세기 • 광원과 물체의 거리에 따라 빛 감쇠 • Surface • 물체의 재질감표현 • “plastic”: standard CGI shader #pointlight.rib Display "pointlight.tiff" "file" "rgb" Format 640 480 1.0 Projection "perspective" "fov" [ 30 ] Translate 0 0 5 WorldBegin LightSource "pointlight" 1 "from" [ -2 2 -2 ] "intensity" [ 7 ] Surface "plastic" Color [ 1 0 0 ] Sphere 1 -1 1 360 WorldEnd

  42. #illuminate.rib Display "illuminate.tiff" "file" "rgb" Projection "perspective" "fov" [20] Translate 0 0 10 WorldBegin LightSource "pointlight" 1 "from" [4 3 -5] "intensity" [16] LightSource "pointlight" 2 "from" [-4 3 -5] "intensity" [16] Surface "plastic" Color [ 1 0 0 ] AttributeBegin Illuminate 1 1 Translate -0.5 0 0 Sphere 1 -1 1 360 AttributeEnd AttributeBegin Illuminate 1 0 Translate 0.5 0 0 Sphere 1 -1 1 360 AttributeEnd WorldEnd Illuminate • Illuminate • Illuminate [0/1] [0/1] [0/1] … • 광원 on/off

  43. Distant light • Distant light • LightSource • “distantlight” • “to” : 광원의 방향 • 거리에 상관없이 빛의 세기 일정 #distantlight.rib Display "distantlight.tiff" "file" "rgb" Projection "perspective" "fov" [ 30 ] Translate 0 0 5 WorldBegin LightSource "distantlight" 1 "to" [ 1 0 0 ] "intensity" [ 1 ] Color [ 1 0 0 ] Surface "plastic" Sphere 1 -1 1 360 WorldEnd

  44. Spot light delta [0.05] delta [0.25] • Spot light • LightSource • “spotlight” • “from” : 광원의 위치 • “to” : 광원의 방향 • “coneangle” : out cone • “conedeltaangle” : inner cone #spotlight.rib Display "spotlight.tiff" "file" "rgb" Projection "perspective" "fov" [ 30 ] Translate 0 0 5 WorldBegin LightSource "spotlight" 2 "from" [-2 2 -2] "to" [ 0 0 0 ] "intensity" [ 7 ] "coneangle" [0.25] "conedeltaangle" [0.05] Color [ 1 0 0 ] Surface "plastic" Sphere 1 -1 1 360 WorldEnd

  45. Ambient light #spotambient.rib Display "spotambient.tiff" "file" "rgb" Projection "perspective" "fov" [ 30 ] Translate 0 0 5 WorldBegin LightSource "ambientlight" 1 "intensity" [ 0.1] LightSource "spotlight" 2 "from" [-2 2 -2] "to" [ 0 0 0 ] "intensity" [ 7 ] "coneangle" [0.25] "conedeltaangle" [0.05] Color [ 1 0 0 ] Surface "plastic" Sphere 1 -1 1 360 WorldEnd • Ambient light • LightSource • “ambientlight” : 주변광 • “intensity” : 빛의 밝기 • “color” [r g b] : 빛의 색깔 Ambient Ambient & Spot light

  46. Shading Language • Many types of shaders are possible: • Light source shaders • Surface shaders • Atmosphere shaders • Volume shaders…etc. • We will discuss only the surface shaders.

  47. Standard Shaders • Standard Shaders • Constant • Matte • Metal • Plastic • Painted plastic • Displacement

  48. Constant #constant.rib Display "constant.tiff" "file" "rgb" Projection "perspective" "fov" [ 30 ] Translate 0 0 5 WorldBegin LightSource "ambientlight" 1 "intensity" [ 0.1] LightSource "spotlight" 2 "from" [-2 2 -2] "to" [ 0 0 0 ] "intensity" [ 7 ] "coneangle" [0.25] "conedeltaangle" [0.05] Color [ 1 0 0 ] Surface "constant" Sphere 1 -1 1 360 WorldEnd • Constant • “constant” : simplest surface • Simpler than the default shader • Surface “constant”

  49. Matte • Matte • Simulate the diffuse scattering of light from a rough surface • Surface “matte” #matte.rib Display “matte.tiff" "file" "rgb" Projection "perspective" "fov" [ 30 ] Translate 0 0 5 WorldBegin LightSource "ambientlight" 1 "intensity" [ 0.1] LightSource "spotlight" 2 "from" [-2 2 -2] "to" [ 0 0 0 ] "intensity" [ 7 ] "coneangle" [0.25] "conedeltaangle" [0.05] Color [ 1 0 0 ] Surface “matte" Sphere 1 -1 1 360 WorldEnd

  50. Metal • Metal • Metal Objects • Reflect bright light, creating a sharp specular highlight • Surface “metal” #metal.rib Display “metal.tiff" "file" "rgb" Projection "perspective" "fov" [ 30 ] Translate 0 0 5 WorldBegin LightSource "ambientlight" 1 "intensity" [ 0.1] LightSource "spotlight" 2 "from" [-2 2 -2] "to" [ 0 0 0 ] "intensity" [ 7 ] "coneangle" [0.25] "conedeltaangle" [0.05] Color [ 1 0 0 ] Surface “metal" Sphere 1 -1 1 360 WorldEnd

More Related