man/man1/pmblur.1

.\" RCSid "$Id: pmblur.1,v 1.4 2007/09/04 17:36:40 greg Exp $"
.TH PMBLUR 1 3/3/98 RADIANCE
.SH NAME
pmblur - generate views for camera motion blurring
.SH SYNOPSIS
.B pmblur
.B speed
.B nsamp
.B v0file
.B v1file
.SH DESCRIPTION
.I Pmblur
takes two viewfiles and generates
.I nsamp
views starting from
.I v0file
and moving towards
.I v1file.
When rendered and averaged together, these views will result in
a picture with motion blur due to a camera changing from v0 to v1
in a relative time unit of 1, whose shutter is open starting at v0 for
.I speed
of these time units.
Either
.I pinterp(1)
or
.I rpict(1)
may be called to do the actual work.
(The given
.I v0file
must also be passed on the command line to the chosen renderer, since
.I pmblur
provides supplemental view specifications only.)\0
.PP
For
.I pinterp,
feed the output of
.I pmblur
to the standard input of
.I pinterp
and apply the
.I \-B
option to blur views together.
In most cases, two pictures with z-buffers at v0 and v1 will
get a satisfactory result, though the perfectionist may wish to
apply the
.I \-ff
option together with the
.I \-fr
option of
.I pinterp.
.PP
To use
.I pmblur
with
.I rpict,
apply the
.I \-S
option to indicate a rendering sequence, and set the
.I \-o
option with a formatted file name to save multiple output
pictures.
When all the renderings are finished, combine them with the
.I pcomb(1)
program, using appropriate scalefactors to achieve an average.
Note that using
.I rpict
is MUCH more expensive than using
.I pinterp,
and it is only recommended if the scene and application
absolutely demand it (e.g. there is prominent refraction that
must be modeled accurately).
.PP
For both
.I pinterp
and
.I rpict,
the computation time will be proportional to the number of views from
.I pmblur.
We have found a
.I nsamp
setting somewhere between 5 and 10 to be adequate for most images.
Relatively larger values are appropriate for faster camera motion.
.PP
The
.I \-pm
option of
.I rpict
may be used instead or in combination to blur animated frames, with
the added advantage of blurring reflections and refractions according
to their proper motion.
However, this option will result in more noise and expense than using
.I pmblur
with
.I pinterp
as a post-process.
If both blurring methods are used, a smaller value should be given to the
.I rpict
.I \-pm
option equal to the shutter speed divided by the number of pmblur views.
This will be just enough to blur the boundaries of the ghosts
which may appear using
.I pmblur
with a small number of time samples.
.SH EXAMPLES
To use
.I pinterp
to simulate motion blur between two frames of a walk-through
animation, where the camera shutter is open for 1/4 of the
interframe distance:
.IP "" .2i
pmblur .25 8 fr1023.hdr fr1024.hdr | pinterp \-B \-vf fr1023.hdr \-x 640 \-y 480
fr1023.hdr fr1023.zbf fr1024.hdr fr1024.zbf > fr1023b.hdr
.SH AUTHOR
Greg Ward
.SH BUGS
Changes in the view shift and lift vectors or the fore and aft
clipping planes are not blurred.
.SH "SEE ALSO"
pcomb(1), pdfblur(1), pinterp(1), pmdblur(1), rcalc(1), rpict(1), vwright(1)
Revision:	1.5
Committed:	Mon Nov 10 19:08:17 2008 UTC (16 years, 11 months ago) by greg
Branch:	MAIN
CVS Tags:	rad4R1, rad4R0
Changes since 1.4:	+3 -3 lines
Log Message:	Changed ".pic" extension to ".hdr" throughout
#	Content
1	.\" RCSid "$Id: pmblur.1,v 1.4 2007/09/04 17:36:40 greg Exp $"
2	.TH PMBLUR 1 3/3/98 RADIANCE
3	.SH NAME
4	pmblur - generate views for camera motion blurring
5	.SH SYNOPSIS
6	.B pmblur
7	.B speed
8	.B nsamp
9	.B v0file
10	.B v1file
11	.SH DESCRIPTION
12	.I Pmblur
13	takes two viewfiles and generates
14	.I nsamp
15	views starting from
16	.I v0file
17	and moving towards
18	.I v1file.
19	When rendered and averaged together, these views will result in
20	a picture with motion blur due to a camera changing from v0 to v1
21	in a relative time unit of 1, whose shutter is open starting at v0 for
22	.I speed
23	of these time units.
24	Either
25	.I pinterp(1)
26	or
27	.I rpict(1)
28	may be called to do the actual work.
29	(The given
30	.I v0file
31	must also be passed on the command line to the chosen renderer, since
32	.I pmblur
33	provides supplemental view specifications only.)\0
34	.PP
35	For
36	.I pinterp,
37	feed the output of
38	.I pmblur
39	to the standard input of
40	.I pinterp
41	and apply the
42	.I \-B
43	option to blur views together.
44	In most cases, two pictures with z-buffers at v0 and v1 will
45	get a satisfactory result, though the perfectionist may wish to
46	apply the
47	.I \-ff
48	option together with the
49	.I \-fr
50	option of
51	.I pinterp.
52	.PP
53	To use
54	.I pmblur
55	with
56	.I rpict,
57	apply the
58	.I \-S
59	option to indicate a rendering sequence, and set the
60	.I \-o
61	option with a formatted file name to save multiple output
62	pictures.
63	When all the renderings are finished, combine them with the
64	.I pcomb(1)
65	program, using appropriate scalefactors to achieve an average.
66	Note that using
67	.I rpict
68	is MUCH more expensive than using
69	.I pinterp,
70	and it is only recommended if the scene and application
71	absolutely demand it (e.g. there is prominent refraction that
72	must be modeled accurately).
73	.PP
74	For both
75	.I pinterp
76	and
77	.I rpict,
78	the computation time will be proportional to the number of views from
79	.I pmblur.
80	We have found a
81	.I nsamp
82	setting somewhere between 5 and 10 to be adequate for most images.
83	Relatively larger values are appropriate for faster camera motion.
84	.PP
85	The
86	.I \-pm
87	option of
88	.I rpict
89	may be used instead or in combination to blur animated frames, with
90	the added advantage of blurring reflections and refractions according
91	to their proper motion.
92	However, this option will result in more noise and expense than using
93	.I pmblur
94	with
95	.I pinterp
96	as a post-process.
97	If both blurring methods are used, a smaller value should be given to the
98	.I rpict
99	.I \-pm
100	option equal to the shutter speed divided by the number of pmblur views.
101	This will be just enough to blur the boundaries of the ghosts
102	which may appear using
103	.I pmblur
104	with a small number of time samples.
105	.SH EXAMPLES
106	To use
107	.I pinterp
108	to simulate motion blur between two frames of a walk-through
109	animation, where the camera shutter is open for 1/4 of the
110	interframe distance:
111	.IP "" .2i
112	pmblur .25 8 fr1023.hdr fr1024.hdr \| pinterp \-B \-vf fr1023.hdr \-x 640 \-y 480
113	fr1023.hdr fr1023.zbf fr1024.hdr fr1024.zbf > fr1023b.hdr
114	.SH AUTHOR
115	Greg Ward
116	.SH BUGS
117	Changes in the view shift and lift vectors or the fore and aft
118	clipping planes are not blurred.
119	.SH "SEE ALSO"
120	pcomb(1), pdfblur(1), pinterp(1), pmdblur(1), rcalc(1), rpict(1), vwright(1)