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

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

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

EditPlus 연동

기본설정 / 사용자도구 [ 그룹이름설정 ] RenderMan [ 추가 프로그램 ] 메뉴제목 : Render

• [ 명령 ] C:\BMRT2.6\bin\rendrib.exe• [ 인수 ] -d $(FileName) [ 디렉토리 ] $(FileDir)

[ 추가 프로그램 ] 메뉴제목 : Shader• [ 명령 ] C:\BMRT2.6\bin\slc.exe• [ 인수 ] $(FileName) [ 디렉토리 ] $(FileDir)

[ 추가 프로그램 ] 메뉴제목 : PreRender• [ 명령 ] C:\BMRT2.6\bin\rgl.exe• [ 인수 ] $(FileName) [ 디렉토리 ] $(FileDir)

[ 추가 프로그램 ] 메뉴제목 : ImageViewer• [ 명령 ] C:\BMRT2.6\bin\iv.exe• [ 인수 ] $(FileNameNoExt).tiff [ 디렉토리 ] $(FileDir)

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_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

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