--- ray/doc/man/man1/rpict.1 2005/06/14 03:34:14 1.10 +++ ray/doc/man/man1/rpict.1 2014/01/25 18:27:39 1.16 @@ -1,4 +1,4 @@ -.\" RCSid "$Id: rpict.1,v 1.10 2005/06/14 03:34:14 greg Exp $" +.\" RCSid "$Id: rpict.1,v 1.16 2014/01/25 18:27:39 greg Exp $" .TH RPICT 1 2/26/99 RADIANCE .SH NAME rpict - generate a RADIANCE picture @@ -70,13 +70,21 @@ A cylindrical panorma may be selected by setting to the letter 'c'. This view is like a standard perspective vertically, but projected on a cylinder horizontally (like a soupcan's-eye view). -Two fisheye views are provided as well; 'h' yields a hemispherical fisheye -view and 'a' results in angular fisheye distortion. +Three fisheye views are provided as well; 'h' yields a hemispherical fisheye +view, 'a' results in angular fisheye distortion, and 's' +results in a planisphere (stereographic) projection. A hemispherical fisheye is a projection of the hemisphere onto a circle. The maximum view angle for this type is 180 degrees. An angular fisheye view is defined such that distance from the center of the image is proportional to the angle from the central view direction. An angular fisheye can display a full 360 degrees. +A planisphere fisheye view maintains angular relationships between lines, +and is commonly used for sun path analysis. +This is more commonly known as a +"stereographic projection," but we avoid the term here so as not to +confuse it with a stereoscopic pair. +A planisphere fisheye can display up to (but not including) 360 degrees, +although distortion becomes extreme as this limit is approached. Note that there is no space between the view type option and its single letter argument. .TP @@ -152,7 +160,7 @@ This is option is useful for generating skewed perspec rendering an image a piece at a time. A value of 1 means that the rendered image starts just to the right of the normal view. -A value of -1 would be to the left. +A value of \-1 would be to the left. Larger or fractional values are permitted as well. .TP .BI -vl \ val @@ -263,7 +271,7 @@ A warning about aiming failure will issued if .I frac is too large. It is usually wise to turn off image sampling when using -direct jitter by setting -ps to 1. +direct jitter by setting \-ps to 1. .TP .BI -ds \ frac Set the direct sampling ratio to @@ -327,13 +335,13 @@ This option may be desirable in conjunction with the .I \-i option so that light sources do not appear in the output. .TP -.BI -sj \ frac -Set the specular sampling jitter to -.I frac. -This is the degree to which the highlights are sampled -for rough specular materials. -A value of one means that all highlights will be fully sampled -using distributed ray tracing. +.BI -ss \ samp +Set the specular sampling to +.I samp. +For values less than 1, this is the degree to which the highlights +are sampled for rough specular materials. +A value greater than one causes multiple ray samples to be sent +to reduce noise at a commmesurate cost. A value of zero means that no jittering will take place, and all reflections will appear sharp even when they should be diffuse. This may be desirable when used in combination with image sampling @@ -357,15 +365,14 @@ accuracy and rendering time. .TP .BR -bv Boolean switch for back face visibility. -With this switch off, back faces of opaque objects will be invisible -to all rays. +With this switch off, back faces of all objects will be invisible +to view rays. This is dangerous unless the model was constructed such that -all surface normals on opaque objects face outward. +all surface normals face outward. Although turning off back face visibility does not save much computation time under most circumstances, it may be useful as a tool for scene debugging, or for seeing through one-sided walls from the outside. -This option has no effect on transparent or translucent materials. .TP .BI -av " red grn blu" Set the ambient value to a radiance of @@ -563,7 +570,8 @@ When "on", pure Monte Carlo sampling is used in all ca .TP .BI -lr \ N Limit reflections to a maximum of -.I N. +.I N, +if N is a positive integer. If .I N is zero, then Russian roulette is used for ray @@ -571,7 +579,7 @@ termination, and the .I -lw setting (below) must be positive. If N is a negative integer, then this sets the upper limit -of reflections past which Russian roulette will not be used. +of reflections past which Russian roulette will be used. In scenes with dielectrics and total internal reflection, a setting of 0 (no limit) may cause a stack overflow. .TP @@ -774,7 +782,7 @@ Set the time between progress reports to A progress report writes the number of rays traced, the percentage completed, and the CPU usage to the standard error. Reports are given either automatically after the specified interval, -or when the process receives a continue (-CONT) signal (see +or when the process receives a continue (\-CONT) signal (see .I kill(1)). A value of zero turns automatic reporting off. .TP @@ -788,9 +796,9 @@ Boolean switch for warning messages. The default is to print warnings, so the first appearance of this option turns them off. .SH EXAMPLE -rpict -vp 10 5 3 -vd 1 -.5 0 scene.oct > scene.pic +rpict \-vp 10 5 3 \-vd 1 \-.5 0 scene.oct > scene.hdr .PP -rpict -S 1 -o frame%02d.pic scene.oct < keyframes.vf +rpict \-S 1 \-o frame%02d.hdr scene.oct < keyframes.vf .SH ENVIRONMENT RAYPATH the directories to check for auxiliary files. .SH FILES