man/man1/ranimate.1

.\" RCSid "$Id: ranimate.1,v 1.10 2008/11/10 19:08:17 greg Exp $"
.TH RANIMATE 1 6/24/98 RADIANCE
.SH NAME
ranimate - compute a RADIANCE animation
.SH SYNOPSIS
.B ranimate
[
.B \-s
][
.B \-n
][
.B \-e
][
.B \-w
]
.B ranfile
.SH DESCRIPTION
.I Ranimate
is an executive program that reads the given
.I ranfile
and makes appropriate calls to
.I rad(1),
.I rpict(1),
.I pinterp(1),
and/or
.I pfilt(1)
to render an animation.
Variables in
.I ranfile
indicate input files, process servers (execution hosts), output
directories and file names, and various other controls and options.
.PP
Normally, commands are echoed to the standard output as they are
executed.
The
.I \-s
option tells
.I ranimate
to do its work silently.
The
.I \-n
option tells
.I ranimate
not to take any action (ie. not to actually execute any commands).
The
.I \-e
option tells
.I ranimate
to explicate all variables used for the animation, including
default values not specified in the input file, and print them on
the standard output.
.PP
The
.I \-w
option turns off warnings about multiply and misassigned variables.
.PP
Normally,
.I ranimate
will produce one animation frame for each view given in the specified
view file.
If an animation has ended or been killed in an incomplete state, however,
.I ranimate
will attempt to pick up where the earlier process left off.
If the process is still running, or was started on another machine,
.I ranimate
will report this information and exit.
.PP
Animation variable assignments appear one per line in
.I ranfile.
The name of the variable is followed by an equals sign
('=') and its value(s).
The end of line may be escaped with a backslash ('\\'), though it is
not usually necessary since additional variable values may be given
in multiple assignments.
Variables that should have only one value are given in upper case.
Variables that may have multiple values are given in lower case.
Variables may be abbreviated by their first three letters, except
for "host", which must have all four.
Comments in
.I ranfile
start with a pound sign ('#') and proceed to the end of line.
.PP
The animation variables, their interpretations and default values
are given below.
.TP 10n
.BR DIRECTORY
The name of the animation directory.
All temporary files generated during the animation will be placed in
this directory, which will be created by
.I ranimate
if it does not exist.
A file named "STATUS" will also be created there, and will contain current
information about the animation process.
This variable has no default value, and its setting is required.
.TP
.BR OCTREE
The name of the octree file for a static scene walk-through
animation.
There is no default value for this variable, and any
setting will be ignored if the
.I ANIMATE
variable is also set (see below).
.TP
.BR ANIMATE
The scene generation command for a dynamic animation.
This command, if given, will be executed with the frame number as the
final argument, and on its standard output it must produce
the complete octree for that frame.
Care must be taken that this command does not create any temporary files
that might collide with same-named files created by other
animation commands running in parallel.
Also, the command should produce no output to the standard error, unless
there is a fatal condition.
(I.e., switch all warnings off;
see the BUGS section, below.)\0
There is no default animation command, and either this variable or the
.I OCTREE
variable must be set.
.TP
.BR VIEWFILE
This variable names a file from which
.I ranimate
may extract the view for each frame in the animation.
This file should contain one valid view per frame, starting with
frame 1 on line 1, regardless of the setting of the
.I START
variable.
An exception is made for a view file with only a single view, which
is used for every frame of a dynamic scene animation.
This variable is required, and there is no default value.
.TP
.BR START
The initial frame number in this animation sequence.
The minimum value is 1, and if a later starting frame is given,
.I ranimate
assumes that the earlier frames are included in some other
.I ranfile,
which has been previously executed.
(See the
.I NEXTANIM
variable, below.)\0
The default value is 1.
.TP
.BR END
The final frame number in this sequence.
The minimum value is equal to the
.I START
frame,
and the default value is computed from the number of views in the
given
.I VIEWFILE.
.TP
.BR EXPOSURE
This variable tells
.I ranimate
how to adjust the exposure for each frame.
As in
.I pfilt,
the exposure setting may be given either as a multiplier or as a
number of f\-stop adjustments (eg. +2 or \-1.5).
Alternatively, a file name may be given, which
.I ranimate
will interpret as having one exposure value per line per frame,
beginning with frame 1 at line 1.
(See also the
.I VIEWFILE
variable, above.)\0
There is no default value for this variable.
If it is not given, an average level will be computed by
.I pfilt
for each frame.
.TP
.BR BASENAME
The base output file name for the final frames.
This string will be passed to the
.I \-o
and
.I \-z
options of rpict, along with appropriate suffixes,
and thus should contain a
.I printf(3)
style integer field to distinguish one frame number from another.
The final frames will use this name with a ".hdr" suffix.
The default value is the assigned
.I DIRECTORY
followed by "/frame%03d".
.TP
.BR host
A host to use for command execution.
This variable may be assigned a host name, followed by an optional
number of parallel processes, followed by an optional
directory (relative to the user's home directory on that machine),
followed by an alternate user name.
Multiple
.I host
assignments may appear.
It is not advisable to specify more than one process on a single-CPU
host, as this just tends to slow things down.
The default value is "localhost", which starts a single process in
the current directory of the local machine.
.TP
.BR RIF
This variable specifies a
.I rad
input file to use as a source of rendering options and other
variable settings.
If given,
.I ranimate
will execute
.I rad
and create an options file to later pass to
.I rpict
or
.I rtrace.
Besides prepending the
.I render
variable,
.I ranimate
will also extract default settings for the common variables:
.I OCTREE,
.I RESOLUTION,
.I EXPOSURE
and
.I pfilt.
Following the file name, overriding variable settings may be given,
which will be passed to
.I rad
on the command line.
Settings with spaces in them should be enclosed in quotes.
The execution of
.I rad
will also update the contents of the octree, if necessary.
There is no default value for this variable.
.TP
.BR DISKSPACE
Specify the amount of disk space (in megabytes) available on the
destination file system for temporary file storage.
.I Ranimate
will coordinate its batch operations based on this amount of storage,
assuming that there is either enough additional space for all the
final frames, or that the given
.I TRANSFER
command will move the finished frames to some other location (see
below).
The default value is 100 megabytes.
.TP
.BR ARCHIVE
After each batch rendering is finished and checked for completeness,
.I ranimate
will execute the given command, passing the names of all the
original pictures and z-buffer files generated by
.I rpict.
(The command is executed in the destination directory, and file names
will be simple.)\0
Normally, the archive command copies the original files to a tape device
or somewhere that they can be retrieved in the event of failure in
the frame interpolation stages.
After the archive command has successfully completed, the original
renderings are removed.
There is no default value for this variable, meaning that the
original unfiltered frames will simply be removed.
Note that the last one or two rendered frames may not be copied, archived
or removed in case there is a another sequence picking up where this
one left off.
.TP
.BR TRANSFER
The command to transfer the completed animation frames.
The shell changes to the destination directory and appends
the names of all the finished frames to this command
before it is executed.
Normally, the transfer command does something such as convert the
frames to another format and/or copy them to tape or some other
destination device before removing them.
The
.I fieldcomb(1)
script may be used to conveniently combine fields into frames for
field-based animations.
If this variable is not given, the final frames are left where they
are.
(See
.I BASENAME,
above.)\0
.TP
.BR RSH
The command to use instead of
.I ssh(1)
to execute commands remotely on another machine.
The arguments and behavior of this program must be identical to the UNIX
.I ssh
command, except that the
.I -l
option will always be used to specify an alternate user name rather than the
.I "user@host"
convention.
The
.I -l
option may or may not appear, but the
.I -n
option will always be used, and the expected starting directory will
be that of the remote user, just as with
.I ssh.
.TP
.BR NEXTANIM
This variable specifies the next
.I ranfile
to use after this sequence is completed.
This offers a convenient means to continue an animation that
requires different control options in different segments.
It is important in this case to correctly set the
.I START
and
.I END
variables in each
.I ranfile
so that the segments do not overlap frames.
.TP
.BR OVERSAMPLE
This variable sets the multiplier of the original image size
relative to the final size given by the
.I RESOLUTION
variable.
This determines the quality of anti-aliasing in the final frames.
A value of 1 means no anti-aliasing, and a value of 3 produces very
good anti-aliasing.
The default value is 2.
(A fractional value may be used for previews, causing low
resolution frames with large, blocky pixels to be produced.)\0
.TP
.BR INTERPOLATE
This variable sets the number of frames to interpolate between each
rendered frame in a static scene walk-through.
Z-buffers for each rendered frame will be generated by
.I rpict,
and
.I pinterp
will be called to perform the actual "tweening."
This results in a potentially large savings in rendering time, but
should be used with caution since certain information may be lost or
inaccurate, such as specular highlights and reflections, and objects
may even break apart if too few renderings are used to interpolate
too much motion.
The default value for this variable is 0, meaning no interpolation.
Interpolation is also switched off if the
.I ANIMATE
variable is specified.
.TP
.BR MBLUR
This variable specifies the fraction of a frame time that the shutter
is simulated as being open for motion blur.
A number of samples may be given as a second argument, which
controls the number of additional frames computed and averaged
together by
.I pinterp.
If this number is less than 2, then bluring is performed by
.I rpict
only, resulting in greater noise than the combination of
.I rpict
and
.I pinterp
used otherwise.
(The default value for number of samples is 5.)\0
The default fraction is 0, meaning no motion blurring.
This option does not currently work with the
.I ANIMATE
variable.
.TP
.BR DBLUR
This variable specifies the aperture diameter for depth-of-field blurring,
in world units.
A number of samples may be given as a second argument, which controls the
number of additional frames computed and averaged together by
.I pinterp.
If this number is less than 2, then blurring is performed by
.I rpict
only, resulting in greater noise than the combination of
.I rpict
and
.I pinterp
used otherwise.
(The default value for number of samples is 5.)\0
To simulate a particular camera's aperture, divide the focal length of
the lens by the f-number, then convert to the corresponding
world coordinate units.
For example, if you wish to simulate a 50mm lens at f/2.0 in
a scene modeled in meters, then you divide 50mm by 2.0 to get 25mm,
which corresponds to an effective aperture of 0.025 meters.
The focus distance is determined by the length of the view directon vector.
The default aperture is 0, meaning no depth-of-field blurring.
.TP
.BR RTRACE
This boolean variable tells
.I ranimate
whether or not to employ
.I rtrace
during frame interpolation using the
.I \-fr
option to
.I pinterp.
If set to True, then the same rendering options and static octree
are passed to
.I rtrace
as are normally used by
.I rpict.
The default value is False.
Note that this variable only applies to static environment
walk-throughs (i.e., no
.I ANIMATE
command).
.TP
.BR RESOLUTION
This variable specifies the desired final picture resolution.
If only a single number is given, this value will be used for both
the horizontal and vertical picture dimensions.
If two numbers are given, the first is the horizontal resolution and
the second is the vertical resolution.
If three numbers are given, the third is taken as the pixel aspect
ratio for the final picture (a real value).
If the pixel aspect ratio is zero, the exact dimensions given will
be those produced.
Otherwise, they will be used as a frame in which the final image
must fit.
The default value for this variable is 640.
.TP
.BR render
This variable may be used to specify additional options to
.I rpict
or
.I rtrace.
These options will appear after the options set automatically by
.I rad,
and thus will override the default values.
.TP
.BR pinterp
This variable may be used to specify additional options to
.I pinterp,
which is used to interpolate frames for a static scene walk-through.
(See the
.I pinterp
man page, and the
.I INTERPOLATE
variable.)\0
Do not use this variable to set the
.I pinterp
.I \-fr
option, but use the
.I RTRACE
setting instead.
.TP
.BR pfilt
This variable may be used to specify additional options to
.I pfilt.
If this variable is given in the
.I ranfile,
then
.I pfilt
will always be used.
(Normally,
.I pfilt
is called only if
.I pinterp
is not needed or automatic exposure is required.)\0
See the
.I pfilt
manual page for details.
.SH EXAMPLES
A minimal input file for
.I ranimate
might look like this:
.IP "" .3i
.nf
::::::::::
sample.ran
::::::::::
# The rad input file for our static scene:
RIF= tutor.rif
# The spool directory:
DIRECTORY= anim1
# The view file containing one view per frame:
VIEWFILE= anim1.vf
# The amount of temporary disk space available:
DISKSPACE= 50   # megabytes
.fi
.PP
Note that most of the variables are not set in this file.
If we only want to see what default values
.I ranimate
would use without actually executing anything, we can invoke it
thus:
.IP "" .2i
ranimate \-n \-e sample.ran
.PP
This will print the variables we have given as well as default
values
.I ranimate
has assigned for us.
Also, we will see the list of commands that
.I ranimate
would have executed had the
.I \-n
option not been present.
.PP
Usually, we execute
.I ranimate
in the background, redirecting the standard output and standard
error to a file:
.IP "" .2i
ranimate sample.ran >& sample.err &
.PP
If we decide that the default values
.I ranimate
has chosen for our variables are not all appropriate, we can add
some more assignments to the file:
.IP "" .3i
.nf
host= rays 3 ~greg/obj/tutor ray        # execute as ray on multi-host "rays"
host= thishost                          # execute one copy on this host also
INTERP= 3                               # render every fourth frame
RES= 1024                               # shoot for 1024x resolution
MBLUR= .25                              # apply camera motion blur
EXP= anim1.exp                          # adjust exposure according to file
pfilt= \-r .9                           # use Gaussian filtering
ARCHIVE= tar cf /dev/nrtape             # save original renderings to tape
.fi
.PP
Note the use of abbreviation for variable names.
.SH FILES
$(DIRECTORY)/STATUS     animation status file
$(DIRECTORY)/*          other temporary files
$(BASENAME).hdr         final animation frames
.SH AUTHOR
Greg Ward
.SH BUGS
Due to the difficulty of controlling processes on multiple execution
hosts, the
.I \-n
option of
.I ranimate
is not useful in the same way as
.I rad
for generating a script of executable commands to render the
sequence.
It may give an idea of the sequence of events, but certain temporary
files and so forth will not be in the correct state if the user
attempts to create a separate batch script.
.PP
If multiple processors are available on a given host and the
.I RTRACE
variable is set to True, then the
.I \-PP
option of
.I rtrace
should be employed, but it is not.
There is no easy way around this problem, but it has only minor
consequences in most cases.
(The
.I \-PP
option is used for
.I rpict,
however.)\0
.I
.PP
The current implementation of the remote shell does not return the
exit status of the remote process, which makes it difficult to
determine for sure if there has been a serious error or not.
Because of this,
.I ranimate
normally turns off warnings on all rendering processes, and takes
any output to standard error from a remote command as a sign that a
fatal error has occurred.
(This also precludes the use of the
.I \-t
option to report rendering progress.)\0
If the error was caused by a process server going down, the server
is removed from the active list and frame recovery takes place.
Otherwise,
.I ranimate
quits at that point in the animation.
.PP
The current execution environment, in particular the RAYPATH variable,
will not be passed during remote command execution, so it is necessary
to set whatever variables are important in the remote startup script
(e.g., ".cshrc" for the C-shell).
This requirement may be circumvented by substituting the
.I on(1)
command for
.I ssh(1)
using the
.I RSH
control variable, or by writing a custom remote execution script.
.PP
If a different remote user name is used,
.I ranimate
first attempts to change to the original user's directory with a
command of the form
.I "cd \~uname".
This works under
.I csh(1),
but may fail under other shells such as
.I sh(1).
.PP
If multiple hosts with different floating point formats are used,
.I pinterp
will fail because the Z-buffer files will be inconsistent.
(Recall that
.I pinterp
is called if INTERPOLATE > 0 and/or MBLUR is assigned.)\0
Since most modern machines use IEEE floating point, this is not
usually a problem, but it is something to keep in mind.
.SH "SEE ALSO"
fieldcomb(1), pfilt(1), pinterp(1), pmblur(1), rad(1),
ran2tiff(1), ranimove(1), rpict(1), ssh(1), rtrace(1)
Revision:	1.11
Committed:	Wed Jun 1 16:59:34 2022 UTC (2 years ago) by greg
Branch:	MAIN
CVS Tags:	rad5R4, HEAD
Changes since 1.10:	+3 -5 lines
Error occurred while calculating annotation data.
Log Message:	docs(ranimate): Clarified exceptions for MBLUR and DBLUR settings
#	Content
1	.\" RCSid "$Id: ranimate.1,v 1.10 2008/11/10 19:08:17 greg Exp $"
2	.TH RANIMATE 1 6/24/98 RADIANCE
3	.SH NAME
4	ranimate - compute a RADIANCE animation
5	.SH SYNOPSIS
6	.B ranimate
7	[
8	.B \-s
9	][
10	.B \-n
11	][
12	.B \-e
13	][
14	.B \-w
15	]
16	.B ranfile
17	.SH DESCRIPTION
18	.I Ranimate
19	is an executive program that reads the given
20	.I ranfile
21	and makes appropriate calls to
22	.I rad(1),
23	.I rpict(1),
24	.I pinterp(1),
25	and/or
26	.I pfilt(1)
27	to render an animation.
28	Variables in
29	.I ranfile
30	indicate input files, process servers (execution hosts), output
31	directories and file names, and various other controls and options.
32	.PP
33	Normally, commands are echoed to the standard output as they are
34	executed.
35	The
36	.I \-s
37	option tells
38	.I ranimate
39	to do its work silently.
40	The
41	.I \-n
42	option tells
43	.I ranimate
44	not to take any action (ie. not to actually execute any commands).
45	The
46	.I \-e
47	option tells
48	.I ranimate
49	to explicate all variables used for the animation, including
50	default values not specified in the input file, and print them on
51	the standard output.
52	.PP
53	The
54	.I \-w
55	option turns off warnings about multiply and misassigned variables.
56	.PP
57	Normally,
58	.I ranimate
59	will produce one animation frame for each view given in the specified
60	view file.
61	If an animation has ended or been killed in an incomplete state, however,
62	.I ranimate
63	will attempt to pick up where the earlier process left off.
64	If the process is still running, or was started on another machine,
65	.I ranimate
66	will report this information and exit.
67	.PP
68	Animation variable assignments appear one per line in
69	.I ranfile.
70	The name of the variable is followed by an equals sign
71	('=') and its value(s).
72	The end of line may be escaped with a backslash ('\\'), though it is
73	not usually necessary since additional variable values may be given
74	in multiple assignments.
75	Variables that should have only one value are given in upper case.
76	Variables that may have multiple values are given in lower case.
77	Variables may be abbreviated by their first three letters, except
78	for "host", which must have all four.
79	Comments in
80	.I ranfile
81	start with a pound sign ('#') and proceed to the end of line.
82	.PP
83	The animation variables, their interpretations and default values
84	are given below.
85	.TP 10n
86	.BR DIRECTORY
87	The name of the animation directory.
88	All temporary files generated during the animation will be placed in
89	this directory, which will be created by
90	.I ranimate
91	if it does not exist.
92	A file named "STATUS" will also be created there, and will contain current
93	information about the animation process.
94	This variable has no default value, and its setting is required.
95	.TP
96	.BR OCTREE
97	The name of the octree file for a static scene walk-through
98	animation.
99	There is no default value for this variable, and any
100	setting will be ignored if the
101	.I ANIMATE
102	variable is also set (see below).
103	.TP
104	.BR ANIMATE
105	The scene generation command for a dynamic animation.
106	This command, if given, will be executed with the frame number as the
107	final argument, and on its standard output it must produce
108	the complete octree for that frame.
109	Care must be taken that this command does not create any temporary files
110	that might collide with same-named files created by other
111	animation commands running in parallel.
112	Also, the command should produce no output to the standard error, unless
113	there is a fatal condition.
114	(I.e., switch all warnings off;
115	see the BUGS section, below.)\0
116	There is no default animation command, and either this variable or the
117	.I OCTREE
118	variable must be set.
119	.TP
120	.BR VIEWFILE
121	This variable names a file from which
122	.I ranimate
123	may extract the view for each frame in the animation.
124	This file should contain one valid view per frame, starting with
125	frame 1 on line 1, regardless of the setting of the
126	.I START
127	variable.
128	An exception is made for a view file with only a single view, which
129	is used for every frame of a dynamic scene animation.
130	This variable is required, and there is no default value.
131	.TP
132	.BR START
133	The initial frame number in this animation sequence.
134	The minimum value is 1, and if a later starting frame is given,
135	.I ranimate
136	assumes that the earlier frames are included in some other
137	.I ranfile,
138	which has been previously executed.
139	(See the
140	.I NEXTANIM
141	variable, below.)\0
142	The default value is 1.
143	.TP
144	.BR END
145	The final frame number in this sequence.
146	The minimum value is equal to the
147	.I START
148	frame,
149	and the default value is computed from the number of views in the
150	given
151	.I VIEWFILE.
152	.TP
153	.BR EXPOSURE
154	This variable tells
155	.I ranimate
156	how to adjust the exposure for each frame.
157	As in
158	.I pfilt,
159	the exposure setting may be given either as a multiplier or as a
160	number of f\-stop adjustments (eg. +2 or \-1.5).
161	Alternatively, a file name may be given, which
162	.I ranimate
163	will interpret as having one exposure value per line per frame,
164	beginning with frame 1 at line 1.
165	(See also the
166	.I VIEWFILE
167	variable, above.)\0
168	There is no default value for this variable.
169	If it is not given, an average level will be computed by
170	.I pfilt
171	for each frame.
172	.TP
173	.BR BASENAME
174	The base output file name for the final frames.
175	This string will be passed to the
176	.I \-o
177	and
178	.I \-z
179	options of rpict, along with appropriate suffixes,
180	and thus should contain a
181	.I printf(3)
182	style integer field to distinguish one frame number from another.
183	The final frames will use this name with a ".hdr" suffix.
184	The default value is the assigned
185	.I DIRECTORY
186	followed by "/frame%03d".
187	.TP
188	.BR host
189	A host to use for command execution.
190	This variable may be assigned a host name, followed by an optional
191	number of parallel processes, followed by an optional
192	directory (relative to the user's home directory on that machine),
193	followed by an alternate user name.
194	Multiple
195	.I host
196	assignments may appear.
197	It is not advisable to specify more than one process on a single-CPU
198	host, as this just tends to slow things down.
199	The default value is "localhost", which starts a single process in
200	the current directory of the local machine.
201	.TP
202	.BR RIF
203	This variable specifies a
204	.I rad
205	input file to use as a source of rendering options and other
206	variable settings.
207	If given,
208	.I ranimate
209	will execute
210	.I rad
211	and create an options file to later pass to
212	.I rpict
213	or
214	.I rtrace.
215	Besides prepending the
216	.I render
217	variable,
218	.I ranimate
219	will also extract default settings for the common variables:
220	.I OCTREE,
221	.I RESOLUTION,
222	.I EXPOSURE
223	and
224	.I pfilt.
225	Following the file name, overriding variable settings may be given,
226	which will be passed to
227	.I rad
228	on the command line.
229	Settings with spaces in them should be enclosed in quotes.
230	The execution of
231	.I rad
232	will also update the contents of the octree, if necessary.
233	There is no default value for this variable.
234	.TP
235	.BR DISKSPACE
236	Specify the amount of disk space (in megabytes) available on the
237	destination file system for temporary file storage.
238	.I Ranimate
239	will coordinate its batch operations based on this amount of storage,
240	assuming that there is either enough additional space for all the
241	final frames, or that the given
242	.I TRANSFER
243	command will move the finished frames to some other location (see
244	below).
245	The default value is 100 megabytes.
246	.TP
247	.BR ARCHIVE
248	After each batch rendering is finished and checked for completeness,
249	.I ranimate
250	will execute the given command, passing the names of all the
251	original pictures and z-buffer files generated by
252	.I rpict.
253	(The command is executed in the destination directory, and file names
254	will be simple.)\0
255	Normally, the archive command copies the original files to a tape device
256	or somewhere that they can be retrieved in the event of failure in
257	the frame interpolation stages.
258	After the archive command has successfully completed, the original
259	renderings are removed.
260	There is no default value for this variable, meaning that the
261	original unfiltered frames will simply be removed.
262	Note that the last one or two rendered frames may not be copied, archived
263	or removed in case there is a another sequence picking up where this
264	one left off.
265	.TP
266	.BR TRANSFER
267	The command to transfer the completed animation frames.
268	The shell changes to the destination directory and appends
269	the names of all the finished frames to this command
270	before it is executed.
271	Normally, the transfer command does something such as convert the
272	frames to another format and/or copy them to tape or some other
273	destination device before removing them.
274	The
275	.I fieldcomb(1)
276	script may be used to conveniently combine fields into frames for
277	field-based animations.
278	If this variable is not given, the final frames are left where they
279	are.
280	(See
281	.I BASENAME,
282	above.)\0
283	.TP
284	.BR RSH
285	The command to use instead of
286	.I ssh(1)
287	to execute commands remotely on another machine.
288	The arguments and behavior of this program must be identical to the UNIX
289	.I ssh
290	command, except that the
291	.I -l
292	option will always be used to specify an alternate user name rather than the
293	.I "user@host"
294	convention.
295	The
296	.I -l
297	option may or may not appear, but the
298	.I -n
299	option will always be used, and the expected starting directory will
300	be that of the remote user, just as with
301	.I ssh.
302	.TP
303	.BR NEXTANIM
304	This variable specifies the next
305	.I ranfile
306	to use after this sequence is completed.
307	This offers a convenient means to continue an animation that
308	requires different control options in different segments.
309	It is important in this case to correctly set the
310	.I START
311	and
312	.I END
313	variables in each
314	.I ranfile
315	so that the segments do not overlap frames.
316	.TP
317	.BR OVERSAMPLE
318	This variable sets the multiplier of the original image size
319	relative to the final size given by the
320	.I RESOLUTION
321	variable.
322	This determines the quality of anti-aliasing in the final frames.
323	A value of 1 means no anti-aliasing, and a value of 3 produces very
324	good anti-aliasing.
325	The default value is 2.
326	(A fractional value may be used for previews, causing low
327	resolution frames with large, blocky pixels to be produced.)\0
328	.TP
329	.BR INTERPOLATE
330	This variable sets the number of frames to interpolate between each
331	rendered frame in a static scene walk-through.
332	Z-buffers for each rendered frame will be generated by
333	.I rpict,
334	and
335	.I pinterp
336	will be called to perform the actual "tweening."
337	This results in a potentially large savings in rendering time, but
338	should be used with caution since certain information may be lost or
339	inaccurate, such as specular highlights and reflections, and objects
340	may even break apart if too few renderings are used to interpolate
341	too much motion.
342	The default value for this variable is 0, meaning no interpolation.
343	Interpolation is also switched off if the
344	.I ANIMATE
345	variable is specified.
346	.TP
347	.BR MBLUR
348	This variable specifies the fraction of a frame time that the shutter
349	is simulated as being open for motion blur.
350	A number of samples may be given as a second argument, which
351	controls the number of additional frames computed and averaged
352	together by
353	.I pinterp.
354	If this number is less than 2, then bluring is performed by
355	.I rpict
356	only, resulting in greater noise than the combination of
357	.I rpict
358	and
359	.I pinterp
360	used otherwise.
361	(The default value for number of samples is 5.)\0
362	The default fraction is 0, meaning no motion blurring.
363	This option does not currently work with the
364	.I ANIMATE
365	variable.
366	.TP
367	.BR DBLUR
368	This variable specifies the aperture diameter for depth-of-field blurring,
369	in world units.
370	A number of samples may be given as a second argument, which controls the
371	number of additional frames computed and averaged together by
372	.I pinterp.
373	If this number is less than 2, then blurring is performed by
374	.I rpict
375	only, resulting in greater noise than the combination of
376	.I rpict
377	and
378	.I pinterp
379	used otherwise.
380	(The default value for number of samples is 5.)\0
381	To simulate a particular camera's aperture, divide the focal length of
382	the lens by the f-number, then convert to the corresponding
383	world coordinate units.
384	For example, if you wish to simulate a 50mm lens at f/2.0 in
385	a scene modeled in meters, then you divide 50mm by 2.0 to get 25mm,
386	which corresponds to an effective aperture of 0.025 meters.
387	The focus distance is determined by the length of the view directon vector.
388	The default aperture is 0, meaning no depth-of-field blurring.
389	.TP
390	.BR RTRACE
391	This boolean variable tells
392	.I ranimate
393	whether or not to employ
394	.I rtrace
395	during frame interpolation using the
396	.I \-fr
397	option to
398	.I pinterp.
399	If set to True, then the same rendering options and static octree
400	are passed to
401	.I rtrace
402	as are normally used by
403	.I rpict.
404	The default value is False.
405	Note that this variable only applies to static environment
406	walk-throughs (i.e., no
407	.I ANIMATE
408	command).
409	.TP
410	.BR RESOLUTION
411	This variable specifies the desired final picture resolution.
412	If only a single number is given, this value will be used for both
413	the horizontal and vertical picture dimensions.
414	If two numbers are given, the first is the horizontal resolution and
415	the second is the vertical resolution.
416	If three numbers are given, the third is taken as the pixel aspect
417	ratio for the final picture (a real value).
418	If the pixel aspect ratio is zero, the exact dimensions given will
419	be those produced.
420	Otherwise, they will be used as a frame in which the final image
421	must fit.
422	The default value for this variable is 640.
423	.TP
424	.BR render
425	This variable may be used to specify additional options to
426	.I rpict
427	or
428	.I rtrace.
429	These options will appear after the options set automatically by
430	.I rad,
431	and thus will override the default values.
432	.TP
433	.BR pinterp
434	This variable may be used to specify additional options to
435	.I pinterp,
436	which is used to interpolate frames for a static scene walk-through.
437	(See the
438	.I pinterp
439	man page, and the
440	.I INTERPOLATE
441	variable.)\0
442	Do not use this variable to set the
443	.I pinterp
444	.I \-fr
445	option, but use the
446	.I RTRACE
447	setting instead.
448	.TP
449	.BR pfilt
450	This variable may be used to specify additional options to
451	.I pfilt.
452	If this variable is given in the
453	.I ranfile,
454	then
455	.I pfilt
456	will always be used.
457	(Normally,
458	.I pfilt
459	is called only if
460	.I pinterp
461	is not needed or automatic exposure is required.)\0
462	See the
463	.I pfilt
464	manual page for details.
465	.SH EXAMPLES
466	A minimal input file for
467	.I ranimate
468	might look like this:
469	.IP "" .3i
470	.nf
471	::::::::::
472	sample.ran
473	::::::::::
474	# The rad input file for our static scene:
475	RIF= tutor.rif
476	# The spool directory:
477	DIRECTORY= anim1
478	# The view file containing one view per frame:
479	VIEWFILE= anim1.vf
480	# The amount of temporary disk space available:
481	DISKSPACE= 50 # megabytes
482	.fi
483	.PP
484	Note that most of the variables are not set in this file.
485	If we only want to see what default values
486	.I ranimate
487	would use without actually executing anything, we can invoke it
488	thus:
489	.IP "" .2i
490	ranimate \-n \-e sample.ran
491	.PP
492	This will print the variables we have given as well as default
493	values
494	.I ranimate
495	has assigned for us.
496	Also, we will see the list of commands that
497	.I ranimate
498	would have executed had the
499	.I \-n
500	option not been present.
501	.PP
502	Usually, we execute
503	.I ranimate
504	in the background, redirecting the standard output and standard
505	error to a file:
506	.IP "" .2i
507	ranimate sample.ran >& sample.err &
508	.PP
509	If we decide that the default values
510	.I ranimate
511	has chosen for our variables are not all appropriate, we can add
512	some more assignments to the file:
513	.IP "" .3i
514	.nf
515	host= rays 3 ~greg/obj/tutor ray # execute as ray on multi-host "rays"
516	host= thishost # execute one copy on this host also
517	INTERP= 3 # render every fourth frame
518	RES= 1024 # shoot for 1024x resolution
519	MBLUR= .25 # apply camera motion blur
520	EXP= anim1.exp # adjust exposure according to file
521	pfilt= \-r .9 # use Gaussian filtering
522	ARCHIVE= tar cf /dev/nrtape # save original renderings to tape
523	.fi
524	.PP
525	Note the use of abbreviation for variable names.
526	.SH FILES
527	$(DIRECTORY)/STATUS animation status file
528	$(DIRECTORY)/* other temporary files
529	$(BASENAME).hdr final animation frames
530	.SH AUTHOR
531	Greg Ward
532	.SH BUGS
533	Due to the difficulty of controlling processes on multiple execution
534	hosts, the
535	.I \-n
536	option of
537	.I ranimate
538	is not useful in the same way as
539	.I rad
540	for generating a script of executable commands to render the
541	sequence.
542	It may give an idea of the sequence of events, but certain temporary
543	files and so forth will not be in the correct state if the user
544	attempts to create a separate batch script.
545	.PP
546	If multiple processors are available on a given host and the
547	.I RTRACE
548	variable is set to True, then the
549	.I \-PP
550	option of
551	.I rtrace
552	should be employed, but it is not.
553	There is no easy way around this problem, but it has only minor
554	consequences in most cases.
555	(The
556	.I \-PP
557	option is used for
558	.I rpict,
559	however.)\0
560	.I
561	.PP
562	The current implementation of the remote shell does not return the
563	exit status of the remote process, which makes it difficult to
564	determine for sure if there has been a serious error or not.
565	Because of this,
566	.I ranimate
567	normally turns off warnings on all rendering processes, and takes
568	any output to standard error from a remote command as a sign that a
569	fatal error has occurred.
570	(This also precludes the use of the
571	.I \-t
572	option to report rendering progress.)\0
573	If the error was caused by a process server going down, the server
574	is removed from the active list and frame recovery takes place.
575	Otherwise,
576	.I ranimate
577	quits at that point in the animation.
578	.PP
579	The current execution environment, in particular the RAYPATH variable,
580	will not be passed during remote command execution, so it is necessary
581	to set whatever variables are important in the remote startup script
582	(e.g., ".cshrc" for the C-shell).
583	This requirement may be circumvented by substituting the
584	.I on(1)
585	command for
586	.I ssh(1)
587	using the
588	.I RSH
589	control variable, or by writing a custom remote execution script.
590	.PP
591	If a different remote user name is used,
592	.I ranimate
593	first attempts to change to the original user's directory with a
594	command of the form
595	.I "cd \~uname".
596	This works under
597	.I csh(1),
598	but may fail under other shells such as
599	.I sh(1).
600	.PP
601	If multiple hosts with different floating point formats are used,
602	.I pinterp
603	will fail because the Z-buffer files will be inconsistent.
604	(Recall that
605	.I pinterp
606	is called if INTERPOLATE > 0 and/or MBLUR is assigned.)\0
607	Since most modern machines use IEEE floating point, this is not
608	usually a problem, but it is something to keep in mind.
609	.SH "SEE ALSO"
610	fieldcomb(1), pfilt(1), pinterp(1), pmblur(1), rad(1),
611	ran2tiff(1), ranimove(1), rpict(1), ssh(1), rtrace(1)