rvu operation

The following are the rvu instructions from the Radiance manual. The rvu program used in SPOT has been compiled on Windows by NREL. It has one bug in the saving of images or view files. When using the pull-down menus, the image save and view file save functions cannot correctly read spaces in either the file name or in the target directory. To get around this you can manually type in the commands in the command window. Some common helpful tasks are:

• Save current view – type “view views/[viewfilename]” to save a current view into the views directory. These typically have a *.vf (view file) or a *.vp (view point) file extension.
• Save current image – type “write images/[imagefilename]” to save the current image into the projects images directory. These should have a *.hdr (high dynamic range) file extension.
• Load saved view – type “last views/[viewfilename]” to load a saved view. SPOT automatically generates 8 views for every model: four perspective views at each corner (sw.vf, se.vf, nw.vf, and ne.vf) and four section views on each side (Wsect.vf, Ssect.vf, Esect.vf, Nsect.vf). The southwest perspective view is automatically loaded, but other views can easily be loaded by typing “last views/Wsect.vf” for example.
• Change aim of current view – type “aim” and then click on the image where you want the new center of view.
• Move view location – press the X,Y,Z arrow buttons to move the view location.
  

NAME
rvu – generate RADIANCE images interactively

SYNOPSIS
rvu [ rpict options ][ −n nproc ][ −o dev ][ −b ][ −pe exposure ][$EVAR ][@file ] octree
rvu[options ] −defaults
rvu−devices

DESCRIPTION
Rvu generates RADIANCE images using octree. (The octree may be givenasthe output of a command enclosed in quotes and preceded by a ‘!’.) 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. Acommand argument beginning with a dollar sign (’$’) is immediately replaced by the contents of the givenenvironment variable. A command argument beginning with an at sign (’@’) is immediately replaced by the contents of the givenfile. The options are the same as for rpict(1), with a few notable exceptions. The −pd, −r,−z, −S, −P,−PP and −t options are not supported, and −o specifies which output device is being used instead of the output file. The −x, −y and −pa options are unnecessary, since rvu scales the display image to the specified output device. Additionally,the −b option improves the display on greyscale monitors, and −pe may be used to set an initial exposure value.

The −n option may be used to specify multiple processes, to accelerate rendering.

In the second form, the default values for the options are printed with a brief explanation. In the third form, the list of supported output devices is displayed.

rvu starts rendering the image from the selected viewpoint and gradually improvesthe resolution of the display until interrupted by keyboard input. rvu then issues a prompt (usually ’:’) and accepts a command line from the user. rvu may also stop its calculation and wait for command input if the resolution of the display has reached the resolution of the graphics device. At this point, it will give the ’done:’ prompt and await further instructions. If rvu runs out of memory due to lack of resources to store its computed image, it will give the ’out of memory:’ prompt. At this prompt, the user can save the image, quit, or evenrestart a new image, although this is not generally recommended on virtual memory machines for efficiencyreasons.

rvu is not meant to be a rendering program, and we strongly recommend that rpict(1) be used instead for that purpose. Since rpict(1) does not store its image in memory or update anydisplay of its output, it is much faster and less wasteful of its resources than rvu. rvu is intended as a quick interactive program for deciding viewpoints and debugging scene descriptions and is not suited for producing polished images.

COMMANDS
Once the program starts, a number of commands can be used to control it. A command is given by its name, which can be abbreviated, followed by its arguments.

aim [mag [ x y z ] ]
Zoom in by mag on point xyz. The view point is held constant; only the view direction and size are changed. If xyz is missing, the cursor is used to select the view center. A negative magnification factor means zoom out. The default factor is one.

ˆC Interrupt. Go to the command line.

exposure [spec ]
Adjust exposure. The number spec is a multiplier used to compensate the average exposure. A value of 1 renormalizes the image to the computed average, which is usually done immediately
after startup. If spec begins with a ’+’ or ’-’, the compensation is interpreted in f-stops (ie. the power of two). If spec begins with an ’=’, an absolute setting is performed. An ’=’ by itself permits interactive display and setting of the exposure. If spec begins with an ’@’, the exposure is adjusted to present similar visibility to what would be experienced in the real environment. If spec is absent, or an ’@’ is followed by nothing, then the cursor is used to pick a specific image location for normalization.

focus [distance]
Set focus distance for depth-of-field sampling. If a distance in world coordinates is absent, then the cursor is used to choose a point in the scene on which to focus. (The focus distance setting does not affect rendering in rvu, butcan be used in rpict with the −pd option to simulate depth-of-field on views savedfrom rvu.)

frame [xmin ymin xmax ymax ]
Set frame for refinement. If coordinates are absent, the cursor is used to pick frame boundaries. If ‘‘all’’ is specified, the frame is reset to the entire image.

free Free cached object structures and associated data. This command may be useful when memory is lowand a completely different viewisbeing generated from the one previous.

last [file ] Restore the previous view. Ifavieworpicture file is specified, the parameters are taken from the last view entry in the file.

L [vw[rfile ] ]
Load parameters for view vw from the rad(1) input file, rfile. Both vw and rfile must be given the first call, but subsequent calls will use the last rfile as a default, and “1” as the default view (ie. the first viewappearing in rfile). If rvu wasstarted by rad, then the rfile parameter will initially default to the rad input file used.

move [mag [ x y z ] ]
Move camera mag times closer to point xyz. Foraperspective projection (or fisheye view), only the viewpoint is changed; the viewdirection and size remain constant. The viewsize must be modified in a parallel projection since it determines magnification. If xyzis missing, the cursor is used to select the viewcenter.Anegative magnification factor decreases the object size. The default factor is one. Care must be taken to avoid moving behind or inside other objects.

new [nproc ]
Restart the image, using the specified number of rendering processes. Usually used after the “set” command.

origin ]
Change vieworigin to the indicated world position xo yo zo looking in the direction xd yd zd. If the direction is missing, the current viewdirection is used. If the origin is missing, the cursor is used to select the vieworigin, and the direction will be determined by the (reoriented) surface normal. The viewtype and size will not be altered, but the up vector may be changed if the newdirection coincides.

pivot angle [ elev[mag [ x y z ] ] ]
Similar to the “move“command, but pivots the viewabout a selected point. The angle is measured in degrees around the viewupvector using the right hand rule, so a positive value pivots the viewer to the right of the selected point. The optional elev is the elevation in degrees from the pivotpoint; positive raises the viewpoint to look downward and negative lowers the view point to look upward.

quit Quit the program.

ˆR Redraw the image. Use when the display gets corrupted. On some displays, occassionally forcing a redrawcan improve appearance, as more color information is available and the driver can makeabetter color table selection.

rotate angle [ elev[mag ] ]
Rotate the camera horizontally by angle degrees using the right-hand rule. A positive value rotates the viewtow ards the left, and a negative value looks to the right. If an elevation is specified, the camera looks upward elev degrees. (Negative means look downward.)

set [var [ val ] ]
Check/change program variable. If var is absent, the list of available variables is displayed. If val is absent, the current value of the variable is displayed and changed interactively. Otherwise, the variable var assumes the value val. Variables include: ambient value (av), ambient value weight (aw), ambient bounces (ab), ambient accuracy(aa), ambient divisions (ad), ambient radius (ar), ambient samples (as), black&white (b), back face visibility (bv), direct jitter (dj), direct sampling (ds), direct threshold (dt), direct visibility (dv), irradiance (i), limit weight (lw), limit recursion (lr), medium extinction (me), medium albedo (ma), medium eccentricity (mg), medium sampling (ms), pixel sample (ps), pixel threshold (pt), specular jitter (sj), specular threshold (st), and uncorrelated sampling (u). Once a variable has been changed, the “new” command can be used to recompute the image with the newparameters. If a program variable is not available here, it may showupunder some other command or it may be impossible to change once the program is running.

trace [xbegybegzbegxdir ydir zdir ]
Trace a ray. If the ray origin and direction are absent, the cursor is used to pick a location in the image to trace. The object intersected and its material, location and value are displayed.

view [file [ comments ] ]
Check/change view parameters. If file is present, the view parameters are appended to a file, followed by comments if any. Alternatively, viewoptions may be given directly on the command line instead of an output viewfile. Otherwise, viewparameters are displayed and changed interactively.

V [vw[rfile ] ]
Append the current viewasview vw in the rad file rfile. Compliment to L command. Note that the viewissimply appended to the file, and previous views with the same name should be removedbefore using the file with rad.

write [file ]
Write picture to file. If argument is missing, the current file name is used.

ˆZ Stop the program. The screen will be redrawn when the program resumes.

ENVIRONMENT
RAYPATH the directories to check for auxiliary files.
DISPLAY_GAMMA the value to use for monitor gamma correction.

AUTHOR
GregWard

SEE ALSO
getinfo(1), lookamb(1), oconv(1), pfilt(1), rad(1), rpict(1), rtrace(1)