The RenderMan Interface - Paul Bourke

More documents

Recommendations

Info

• No attribute inheritance should be assumed unless implicit in the definition of the User Entity (i.e., within a hierarchy). • No attribute should be exported except to establish either global or local defaults. The RenderMan Specification provides block structuring to organize the components of a RIB file. Although the use of blocks is only required for frame and world constructs by the Specification, the liberal use of attribute and transform blocks is encouraged. A modeler enables a Render Manager to freely manipulate, rearrange, or delete scene elements (frames, cameras, lights, User Entities) by carefully bounding these elements in the RIB file according to scope. A Render Manager might, for example, strip all of the frames out of a RIB file and distribute them around a network of rendering servers. This, of course, is only possible if the RIB file has been structured in such a way as to bound those things pertaining to a given frame within its frame block and those things pertaining to all frames outside and before all frame blocks. User Entities A User Entity couples a collection of geometric primitives and/or User Entities with shading and geometric attributes. As such it introduces a level of scope that is more local than that implied by the RenderMan world block. Typically, the term User Entity refers to a geometric element within a scene whose attributes or position a user may wish to modify or tweak. Because there is some computational expense associated with attribute block structuring, there is an intrinsic trade-off between control over individual User Entities and rendering time/memory requirements. At one extreme, the entire scene is made up of one User Entity within one attribute block. At the other extreme, each polygon is a User Entity and the renderer is forced to spend most of its time managing the graphics state. Modeling programs and their users may wish to carefully weigh this trade-off. The Scoping Conventions above prescribe the following User Entity Conventions: • All User Entities must be delimited by an attribute block. • All User Entities must have an identifier attribute that uniquely characterizes that Entity to the user. Two special identifier attributes are provided to distinguish between Entities organized by a geometric relationship (the name identifier) and Entities organized according to material makeup (the shadinggroup identifier). • A User Entity must be completely described within its attribute block. Nonportable options and attributes The following list of RIB requests are restricted as they either limit the device independence of the file or they control rendering quality or speed parameters. Render managers should provide this kind of control to users at render time. The inclusion of these restricted requests by a modeler should indicate to a Render Manager that they are, in some sense, mandatory. When including nonportable options or attributes in the RIB file, they should be located contiguously (according to scope) in a RIB file. 187
Attribute Format PixelFilter ShadingRate ColorSamples FrameAspectRatio PixelSamples Cropwindow Imager PixelVariance Exposure Option Quantize D.1.3 Conventions for structural hints The ‘##’ character sequence is used to designate structural hints. Any characters found after these special characters and before the next newline character are construed as special hints intended for Render Managers. Such hints should conform to the conventions outlined herein and should provide structural, resource, or administrative information which cannot easily be incorporated into or derived from the standard RIB stream. The same scoping considerations which apply to RIB should also be applied toward special comments. Header information Header information must be located immediately beginning any conforming RIB file. These hints should provide scene-global administrative and resource information. Header entries should precede any RIB requests and must be contiguous. If a header entry appears twice in a file, the first occurrence should be considered to be the true value. ##RenderMan RIB-Structure 1.1 [ keyword ] This entry should be the first line in a conforming RIB file. Its inclusion indicates full conformance to these specifications. The addition of the special keyword, Entity, specifies that the file conforms to the User Entity conventions described in the Rib Entity Files section. ##Scene name This entry allows a scene name to be associated with the RIB file. ##Creator name Indicates the file creator (usually the name of the modeling or animation software). ##CreationDate time Indicates the time that the file was created. It is expressed as a string of characters and may be in any format. ##For name Indicates the user name or user identifier (network address) of the individual for whom the frames are intended. ##Frames number Indicates the number of frames present in the file. ##Shaders shader1, shader2, ... Indicates the names of nonstandard shaders required. When placed in the header of a RIB file, any nonstandard shaders that appear in the entire file should be listed. When 188
Page 1 and 2:
The RenderMan Interface Version 3.2
Page 3 and 4:
TABLE OF CONTENTS List of Figures L
Page 5 and 6:
12.1 Surface Shaders . . . . . . .
Page 7 and 8:
Section I DIFFERENCES BETWEEN VERSI
Page 9 and 10:
LIST OF TABLES 4.1 Camera Options .
Page 11 and 12:
PREFACE This document is version 3.
Page 13 and 14:
Section 1 INTRODUCTION The RenderMa
Page 15 and 16:
created using this language. This l
Page 17 and 18:
Depth of Field The ability to simul
Page 19 and 20:
typedef RtPointer typedef RtPointer
Page 21 and 22:
RiContext (ctx1); ... There is no R
Page 23 and 24:
Section 3 RELATIONSHIP TO THE RENDE
Page 25 and 26:
through the interface. Any place wh
Page 27 and 28:
RtContextHandle RiGetContext ( void
Page 29 and 30:
RiWorldBegin (); ... RiColor (...);
Page 31 and 32:
Camera Option Type Default Descript
Page 33 and 34:
ottom top left right Screen Window
Page 35 and 36:
EXAMPLE RiFrameAspectRatio (4.0/3.0
Page 37 and 38:
not support the special projection
Page 39 and 40:
This procedure sets the times at wh
Page 41 and 42:
Output depth values are the camera-
Page 43 and 44:
A particular renderer implementatio
Page 45 and 46:
Renderers may additionally produce
Page 47 and 48:
The number of color components, n,
Page 49 and 50:
RiAttributeBegin () RiAttributeEnd
Page 51 and 52:
RIB BINDING Color c0 c1... cn Color
Page 53 and 54:
An area light source is defined by
Page 55 and 56:
The sequencenumber is the integer l
Page 57 and 58:
4.2.5 Displacement shading The grap
Page 59 and 60:
SEE ALSO RiExterior RiAtmosphere Ri
Page 61 and 62:
Matte onoff EXAMPLE RiMatte (RI TRU
Page 63 and 64:
object foo2 will be drawn when the
Page 65 and 66:
the exterior is the region adjacent
Page 67 and 68:
RiIdentity ( ); SEE ALSO RiTransfor
Page 69 and 70:
RiScale ( RtFloat sx, RtFloat sy, R
Page 71 and 72:
4.3.2 Transformation stack Transfor
Page 73 and 74:
Section 5 GEOMETRIC PRIMITIVES The
Page 75 and 76:
Information Name Type Class Floats
Page 77 and 78:
No checking is done by the RenderMa
Page 79 and 80:
5.2 Patches Patches can be either u
Page 81 and 82:
U V 0 1 2 3 12 13 14 15 4 5 6 7 8 9
Page 83 and 84:
10 x 7 Aperiodic Bezier Bicubic Pat
Page 85 and 86:
SEE ALSO 2 2 [ 0 0 1 1 ] 0 1 ”Pw
Page 87 and 88:
parameterlist is a list of token-ar
Page 89 and 90:
Requests a sphere defined by the fo
Page 91 and 92:
Hyperboloid 0 0 0 .5 0 0 270 ”Cs
Page 93 and 94:
z N z V point2 height U x x y 0 max
Page 95 and 96:
particle. If a primitive variable i
Page 97 and 98:
The code array is a sequence of mac
Page 99 and 100:
is an array of floats that define t
Page 101 and 102:
The helper program generates geomet
Page 103 and 104:
Procedural ”DynamicLoad” [ ”m
Page 105 and 106:
SolidBegin ( ”difference” ); So
Page 107 and 108:
Section 6 MOTION Some rendering pro
Page 109 and 110:
Transformations Geometry Shading Ri
Page 111 and 112:
channels (usually an RGB color) can
Page 113 and 114:
Image Forward Axis Up Axis Right Ax
Page 115 and 116:
ErrorHandler ”ignore” ErrorHand
Page 117 and 118:
Part II The RenderMan Shading Langu
Page 119 and 120:
spaces (such as CMYK or pseudocolor
Page 121 and 122:
transmit reflect transmit P E light
Page 123 and 124:
Section 10 RELATIONSHIP TO THE REND
Page 125 and 126:
Section 11 TYPES The Shading Langua
Page 127 and 128:
Coordinate System ”shader” ”c
Page 129 and 130:
As in C, individual array elements
Page 131 and 132:
Light Source E Vantage Point N L Il
Page 133 and 134:
Surface Element to Illuminate L N I
Page 135 and 136:
Name Type Storage Class Description
Page 137 and 138:
• conditional execution, • loop
Page 139 and 140:
This example integrates over a hemi
Page 141 and 142:
Shader instance variable values can
Page 143 and 144:
} return 2 * (vector noise(p)) - 1;
Page 145 and 146:
These functions compute power and i
Page 147 and 148: The actual change in a variable is
Page 149 and 150: Return a unit vector in the directi
Page 151 and 152: Return surface normal given a point
Page 153 and 154: diffuse returns the diffuse compone
Page 155 and 156: prevent aliasing. If one set of tex
Page 157 and 158: 15.7.3 Shadow depth maps Shadow dep
Page 159 and 160: These functions access the value of
Page 161 and 162: The standard data names supported b
Page 163 and 164: } Oi = sum; Ci = Cs * Oi * (Ka + Kd
Page 165 and 166: path of the ray. The input Ci and O
Page 167 and 168: A.2.3 Metal surface surface metal(
Page 169 and 170: distantlight( float intensity = 1;
Page 171 and 172: A.6 Imager Shaders A.6.1 Background
Page 173 and 174: variable definitions ; variables va
Page 175 and 176: triple sixteentuple arrayindex: [ e
Page 177 and 178: Logical expressions have the value
Page 179 and 180: typedef RtPointer RtContextHandle;
Page 181 and 182: RiOptionV(RtToken name, RtInt n, Rt
Page 183 and 184: RtInt n, RtToken tokens[], RtPointe
Page 185 and 186: #define RIE_NOTATTRIBS ((RtInt)26)
Page 187 and 188: Comments Any occurrence of the ’#
Page 189 and 190: In the following sections the synta
Page 191 and 192: C.2.2 Error handling There are two
Page 193 and 194: adhandle badparamlist badripcode ba
Page 195 and 196: v e r s i o n 212 # version 003 007
Page 197: Using RIB File structuring conventi
Page 201 and 202: ##Include filename This entry allow
Page 203 and 204: D.2.1 RIB Entity File example ##Ren
Page 205 and 206: Motion Blur Programmable Shading Di
Page 207 and 208: } E.4 Gaussian Filter RtFloat RiGau
Page 209 and 210: Appendix G RENDERMAN INTERFACE QUIC
Page 211 and 212: Function RiOpacity (color) RiOption
Page 213 and 214: Geometric Primitives (continued) Fu
Page 215 and 216: Function abs(x) Math Functions Desc
Page 217 and 218: Function area(P) calculatenormal(P)
Page 219 and 220: Texture Mapping Functions Function
Page 221 and 222: RiInterior 47 RiLightSource 42 RiMa
Page 223 and 224: and uniform variables on an RiNuPat
Page 225 and 226: Statement About Pixar’s Copyright
show all

The RenderMan Interface - Paul Bourke

Create successful ePaper yourself

Delete template?

Save as template?