renderman (introduction)
DESCRIPTION
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 - PowerPoint PPT PresentationTRANSCRIPT
RenderMan(Introduction)
Objective
Understanding of graphics algorithms Rendering pipeline
Understanding of Technical Director’s role Learning the Shading Language
Notion of Shader
Computer graphical Image Synthesis
RenderMan – A Brief History
Using BMRT
The RIB File
The Shading Language
Writing a Shader
Lecture Outline
Computer graphical Image Synthesis : Image Synthesis
Three routes to image synthesis
Computer graphical Image Synthesis : Rendering
A renderer being fed a scene description
Computer graphical Image Synthesis : Rendering
RenderMan converts RIB inputs into images
RIB: Renderman Interface Bytestream
Computer graphical Image Synthesis : Rendering
Stages in a classical rendering pipeline
Object Space
World Space
Camera View
Clipping
Culling
Final Result
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
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.
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
Movies containing RenderMan-generated imagery
RenderMan Interface
RenderMan Interface
RenderMan Interface Bytestream (RIB): Geometry The scene description language (.rib) can be created by a C progra
m, generated by the modeler, or typed manually The scene description file defined the geometry and some renderin
g 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
RenderMan Interface
RIB as an interface between modelers and renderers
RIB File Structure
Rendering program
RenderMan compliant renderer Pixar’s Photorealistic RenderMan (PRMan) Exluna’s BMRT, Entropy ART’s RenderDrive
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
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: BMRTHOMEValue: C:\BMRT2.6\ Variable: SHADERS Value: C:\BMRT2.6\shaders
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
Test iv• C:\BMRT2.6\examples\> c:\BMRT2.6\bin\iv balls1.tif
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
A Simple Scene
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 2 만큼 이동• Sphere radius: 1, zmin: -1, zmax: 1, theta: 360
#min.rib - a minimal scene Display "min.tiff" "file" "rgb" Projection "perspective" WorldBegin
Translate 0 0 2 Sphere 1 -1 1 360
WorldEnd
Transformation
Transformation Translate x y z Scale x y z Rotate angle x y z TransformBegin TransformEnd
# 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
Color
ColorColor [ red green blue ] 0~1 AttributeBegin : 속성 설정 시작 AttributeEnd : 속성 설정 종료
# 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
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
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
Blocks
WorldBegin, WorldEnd FrameBegin, FrameEnd frameno AttributeBegin, AttributeEnd TransformBegin, TransformEnd Stacking must always be balanced
AttributeBeginTransformBeginAttributeEndTransformEnd is not legal
Simple Surface
Parametric Quadrics Sphere Cone Cylinder Disk Hyperboloid Paraboloid Torus
Simple Surface
SphereSphere <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
Simple Surface
CylinderCylinder <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
Simple Surface
ConeCone <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
Simple Surface
ParaboloidParaboloid <radius_at_zmax> <zmin> <zmax> <sweep_angl
e># 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
Simple Surface
HyperboloidHyperboloid <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
Simple Surface
TorusTorus <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
Simple Surface
DiskDisk <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
Simple Surface
PolygonPolygon "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
Convex Concave
Simple Surface
PointsPolygonPointsPolygon [ 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
Convex Concave
Patches
Patches Provide curved surface
Patch “type” “P” [...... points..] Type : bilinear , bicubic
Ordering of Points
# 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
Bilinear #curved.ribDisplay "curved.tiff" "file" "rgb"Projection "perspective" "fov" [ 20 ]Translate -0.5 -0.5 4WorldBegin 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 01 0 00.4 1 1 #MOVED BACK0.6 1 -1] #MOVED FORWARDS
WorldEnd
Patches
Bicubic #cubic.ribDisplay "cubic.tiff" "file" "rgb"Projection "perspective" "fov" [ 30 ]Translate -0.5 -0.5 3WorldBegin 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 0Patch "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
Lighting
Lighting Point light Distant light Spot light Ambient light
Point light
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
intensity [7] intensity [14]
Illuminate
Illuminate Illuminate [0/1] [0/1] [0/1] …
• 광원 on/off
#illuminate.ribDisplay "illuminate.tiff" "file" "rgb"Projection "perspective" "fov" [20]Translate 0 0 10WorldBegin
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
AttributeEndWorldEnd
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
Spot light
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
delta [0.05] delta [0.25]
Ambient light
Ambient light LightSource
• “ambientlight” : 주변광 • “intensity” : 빛의 밝기• “color” [r g b] : 빛의 색깔
#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 Ambient & Spot light
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.
Standard Shaders
Standard Shaders Constant Matte Metal Plastic Painted plastic Displacement
Constant
Constant “constant” : simplest surface
• Simpler than the default shader
Surface “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
Matte
Matte Simulate the diffuse scattering
of light from a rough surface Surface “matte”
#matte.ribDisplay “matte.tiff" "file" "rgb"Projection "perspective" "fov" [ 30 ]Translate 0 0 5WorldBegin 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
Metal
Metal Metal Objects
• Reflect bright light, creating
a sharp specular highlight
Surface “metal”
#metal.ribDisplay “metal.tiff" "file" "rgb"Projection "perspective" "fov" [ 30 ]Translate 0 0 5WorldBegin 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
Plastic
Plastic Combine both a diffuse and
a specular component Surface “plastic”
# plastic.ribDisplay “plastic.tiff" "file" "rgb"Projection "perspective" "fov" [ 30 ]Translate 0 0 5WorldBegin 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
Painted plastic
Painted plastic Surface “paintedplastic” “texturename” : 텍스춰
#painted.ribDisplay "painted.tiff" "file" "rgb"Projection "perspective" "fov" [ 30 ]Translate 0 0 5WorldBegin 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 "paintedplastic"
"texturename" ["swirl.tiff"]Rotate 90 1 0 0Sphere 1 -1 1 360
WorldEnd
swirl.tiff
Displacement
Displacement Surface “plastic” Displacement “dented”
• In addition to a surface shader
#dented.ribDisplay "dented.tiff" "file" "rgb"Projection "perspective" "fov" [ 30 ]Translate 0 0 5WorldBegin 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"Displacement "dented"Sphere 1 -1 1 360
WorldEnd