Radiance Commands

This section provides background information on the Radiance commands used by the IES interface.

 

These commands are:

 

·       falsecolor

·       findglare

·       gensky

·       getinfo

·       glarendx

·       ies2rad

·       oconv

·       pfilt

·       rpict

 

The following descriptions and command options have been abbreviated.

 

 

falsecolor - make a false colour Radiance picture.

 

 

falsecolor [-i input][-p picture][-cb|-cl][-e][-s scale][-l label][-n ndivs]

[-log decades][-m mult][-r redv][-g grnv][-b bluv]

 

 

falsecolor produces a false colour picture for lighting analysis. Input is a rendered Radiance picture. If contour lines are desired rather than just false colour, the -cl option can be used. The -cb option produces contour bands instead of lines, where the thickness of the bands is related to the rate of change in the image.

 

 

findglare - locate glare sources in a Radiance scene.

 

 

findglare [-v][-ga angles][-t threshold][-r resolution][-c][-p picture]

[view options] [[rtrace options] octree]

 

 

findglare locates sources of glare in a specific set of horizontal directions by computing luminance samples from a Radiance picture and/or octree.

 

If only an octree is given, findglare calls rtrace to compute the samples it needs. If both an octree and a picture are specified, findglare calls rtrace only for samples that are outside the frame of the picture. If findglare does not have an octree and the picture does not completely cover the area of interest, a warning will be issued and everything outside the picture will be treated as if it were black. It is preferable to use a picture with a fisheye view and a horizontal and vertical size of at least 180 degrees (more horizontally if the -ga option is used - see below). Note that the picture file must contain correct view specifications, as maintained by rpict, rview, pfilt and pinterp. Specifically, findglare will not work on pictures processed by pcompos or pcomb. It is also essential to give the proper rtrace options when an octree is used so that the calculated luminance values are correct.

 

The output of findglare is a list of glare source directions, solid angles and average luminances, plus a list of indirect vertical illuminance values as a function of angle. Angles are measured in degrees from the view centre, with positive angles to the left and negative angles to the right.

 

By default, findglare only computes glare sources and indirect vertical illuminance for the given view (taken from the picture if none is specified). If the view direction is not horizontal to begin with (i.e. perpendicular to the view up vector), findglare will substitute the closest horizontal direction as its view centre. The -ga option can be used to specify a set of directions to consider about the centre of view. This specification is given by a starting angle, ending angle, and step angle like so:

 

 

All angles must be whole degrees within the range 1 to 180. Multiple angle ranges may be separated by commas, and individual angles may be given without the ending and step angles. Note that findglare will complain if the same angle is given twice either explicitly or implicitly by two ranges.

 

findglare normally identifies glare sources as directions that are brighter than 7 times the average luminance level. It is possible to override this determination by giving an explicit luminance threshold with the -t option. The idea is to pick a threshold that is well above the average level but smaller than the source areas.

 

 

gensky - generate a Radiance description of the sky.

 

 

gensky month day time [ options ] [ -f file ]

gensky -ang altitude azimuth [ options ] [ -f file ]

gensky -defaults

 

 

gensky produces a Radiance scene description for the CIE standard sky distribution at the given month, day and time. By default, the time is interpreted as local standard time on a 24-hour clock. The time value may be given either as decimal hours, or using a colon to separate hours and minutes. The output sky distribution is given as a brightness function, skyfunc. Its value is in watts/steradian/meter2. The x-axis points east, the y-axis points north, and the z-axis corresponds to the zenith. The actual material and surface(s) used for the sky is left up to the user.

 

gensky supports the following sky options:

 

·       -s - sunny sky without sun.

·       +s - sunny sky with sun.

·       -c - CIE overcast day.

·       -I - intermediate sky without sun.

·       +I - intermediate sky with sun.

·       -u - uniform cloudy sky.

 

 

getinfo - get header information from a Radiance file.

 

 

getinfo [ -d ][ file .. ]

getinfo -

 

 

 

getinfo reads the header of each Radiance file and writes it to the standard output. Octree and picture files are in a binary format, which makes it difficult to determine their content. Therefore, a few lines of text are placed at the beginning of each file by the Radiance program that creates it (usually rpict).

 

 

glarendx - calculate glare index.

 

 

glarendx -t type [ -h ] [-o outputfile] [ glarefile ]

 

 

glarendx computes the selected glare index type from the given glarefile produced by findglare. glarendx computes one value for each (indirect illuminance) angle in the input file.

 

glarendx understands the following arguments for type:

 

·       guth_vcp - Guth Visual Comfort Probability

·       cie_cgi - CIE Glare Index (Einhorn)

·       ugr - Unified Glare Rating

·       brs_gi - BRS Glare Index

·       dgi - Daylight Glare Index

·       guth_dgr - Guth Disability Glare Rating

·       vert_dir - Direct Vertical Illuminance

·       vert_ill - Total Vertical Illuminance

·       vert_ind - Indirect Vertical Illuminance

 

The Rad4D interface uses the “guth_vcp” and the “cie_cgi” options.

 

 

ies2rad - convert IES luminaire data to Radiance description.

 

 

 

ies2rad [ options ] [ input .. ]

 

 

ies2rad converts one or more IES luminaire data files to the equivalent Radiance scene description. The light source geometry will always be centred at the origin aimed in the negative z direction, with the 0 degree plane along the x-axis. Usually, two output files will be created for every input file, one scene file (with a *.rad suffix) and one data file (with a *.dat suffix). The root portion of the output file names will be the same as the corresponding input file. The output files will be created in the current directory (no matter which directory the input files came from.

 

The IES luminaire data files are created by Flucs when lights are assigned to the model.

 

 

ocony - create an octree from a Radiance scene description.

 

 

oconv [-i octree | -b xmin ymin zmin size] [-n  objlim ] [-r maxres ] [-f]

[-w][-] [input ..]

 

 

oconv adds each scene description input to octree and sends the result to the standard output.

 

The -f option produces a frozen octree containing all the scene information. Normally, only a reference to the scene files is stored in the octree, and changes to those files may invalidate the result.

 

Programs will abort with a "stale octree" message if they detect any dangerous inconsistencies between the octree and the input files.

 

 

 

There are five basic error types reported by oconv:

 

·       warning - a non-fatal input-related error.

·       fatal - an unrecoverable input-related error.

·       system - a system-related error.

·       internal - a fatal error related to program limitations.

·       consistency - a program-caused error.

 

Most errors are self-explanatory. However, the following internal errors should be mentioned.

 

·       Too many scene files - reduce the number of scene files by combining them or using calls to xform within files to create a hierarchy.

 

·       Set overflow in addobject (id) - this error occurs when too many surfaces are close together in a scene. Sometimes a dense scene can be accommodated by increasing the maximum resolution (by powers of two) using the -r option, but usually this error indicates something is wrong. Either too many surfaces are lying right on top of each other, or the bounding cube is inflated from an oversized object or an improper -b specification. Chances are the surface "id" is near one of those causing the problem.

 

·       Hash table overflow in fullnode - this error is caused by too many surfaces. If it is possible to create an octree for the scene at all, it will have to be done in stages using the -i option.

 

 

pfilt - filter a Radiance picture.

 

 

pfilt [ options ] [ file ]

pfilt performs anti-aliasing and scaling on a Radiance picture. The program makes two passes on the picture file in order to set the exposure to the correct average value.

 

Input is usually the “raw” file created by rpict.

 

 

 

 

rpict - generate a Radiance picture.

 

 

rpict [ options ] [ $EVAR ] [ @file ] [ octree ]

 

 

rpict generates a picture from the Radiance scene given in the octree and sends it to the standard output. Options specify the viewing parameters as well as giving some control over the calculation. Options may be given on the command line and/or read from the environment and/or read from a file. A command argument beginning with the '@' sign is immediately replaced by the contents of the given file. Most options are followed by one or more arguments, which must be separated from the option and each other by white space.

 

The Rad4D call to this module references the *.rdv file and the *.rdp file and output is redirected to the “raw” file.