man/man1/pmdblur.1

.\" RCSid "$Id: pmdblur.1,v 1.2 2005/01/18 20:19:56 greg Exp $"
.TH PMDBLUR 1 1/17/05 RADIANCE
.SH NAME
pmdblur - generate views for combined camera motion and depth blurring
.SH SYNOPSIS
.B pmdblur
.B speed
.B aperture
.B nsamp
.B v0file
.B v1file
.SH DESCRIPTION
.I Pmdblur
takes two viewfiles and generates
.I nsamp
views starting from
.I v0file
and moving towards
.I v1file,
simulating an aperture of diameter
.I aperture
in world coordinate units.
When rendered and averaged together, these views will result in
a picture with motion and depth-of-field
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 pmdblur
provides supplemental view specifications only.)\0
.PP
For
.I pinterp,
feed the output of
.I pmdblur
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 pmdblur
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 pmdblur.
We have found a
.I nsamp
setting somewhere between 7 and 15 to be adequate for most images.
Relatively larger values are appropriate for faster camera motion.
.PP
The
.I \-pm
and/or
.I \-pd
options 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 pmdblur
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 samples, and the
.I \-pd
option equal to the aperture divided by the number of samples.
This will be just enough to blur the boundaries of the ghosts
which may appear using
.I pmdblur
with a small number of time samples.
.PP
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.
.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 with an aperture of 0.1 world units:
.IP "" .2i
pmdblur .25 .1 8 fr1023.pic fr1024.pic | pinterp \-B \-vf fr1023.pic \-x 640 \-y 480
fr1023.pic fr1023.zbf fr1024.pic fr1024.zbf > fr1023b.pic
.SH AUTHOR
Greg Ward
.SH "SEE ALSO"
pcomb(1), pdfblur(1), pinterp(1), pmblur(1), rcalc(1), rpict(1), vwright(1)
Revision:	1.3
Committed:	Tue Sep 4 17:36:40 2007 UTC (16 years, 8 months ago) by greg
Branch:	MAIN
CVS Tags:	rad3R9
Changes since 1.2:	+4 -3 lines
Log Message:	Added backslashes in front of hyphens (thanks to Bernd Zeimetz for his effort)
#	Content
1	.\" RCSid "$Id: pmdblur.1,v 1.2 2005/01/18 20:19:56 greg Exp $"
2	.TH PMDBLUR 1 1/17/05 RADIANCE
3	.SH NAME
4	pmdblur - generate views for combined camera motion and depth blurring
5	.SH SYNOPSIS
6	.B pmdblur
7	.B speed
8	.B aperture
9	.B nsamp
10	.B v0file
11	.B v1file
12	.SH DESCRIPTION
13	.I Pmdblur
14	takes two viewfiles and generates
15	.I nsamp
16	views starting from
17	.I v0file
18	and moving towards
19	.I v1file,
20	simulating an aperture of diameter
21	.I aperture
22	in world coordinate units.
23	When rendered and averaged together, these views will result in
24	a picture with motion and depth-of-field
25	blur due to a camera changing from v0 to v1
26	in a relative time unit of 1, whose shutter is open starting at v0 for
27	.I speed
28	of these time units.
29	Either
30	.I pinterp(1)
31	or
32	.I rpict(1)
33	may be called to do the actual work.
34	(The given
35	.I v0file
36	must also be passed on the command line to the chosen renderer, since
37	.I pmdblur
38	provides supplemental view specifications only.)\0
39	.PP
40	For
41	.I pinterp,
42	feed the output of
43	.I pmdblur
44	to the standard input of
45	.I pinterp
46	and apply the
47	.I \-B
48	option to blur views together.
49	In most cases, two pictures with z-buffers at v0 and v1 will
50	get a satisfactory result, though the perfectionist may wish to
51	apply the
52	.I \-ff
53	option together with the
54	.I \-fr
55	option of
56	.I pinterp.
57	.PP
58	To use
59	.I pmdblur
60	with
61	.I rpict,
62	apply the
63	.I \-S
64	option to indicate a rendering sequence, and set the
65	.I \-o
66	option with a formatted file name to save multiple output
67	pictures.
68	When all the renderings are finished, combine them with the
69	.I pcomb(1)
70	program, using appropriate scalefactors to achieve an average.
71	Note that using
72	.I rpict
73	is MUCH more expensive than using
74	.I pinterp,
75	and it is only recommended if the scene and application
76	absolutely demand it (e.g. there is prominent refraction that
77	must be modeled accurately).
78	.PP
79	For both
80	.I pinterp
81	and
82	.I rpict,
83	the computation time will be proportional to the number of views from
84	.I pmdblur.
85	We have found a
86	.I nsamp
87	setting somewhere between 7 and 15 to be adequate for most images.
88	Relatively larger values are appropriate for faster camera motion.
89	.PP
90	The
91	.I \-pm
92	and/or
93	.I \-pd
94	options of
95	.I rpict
96	may be used instead or in combination to blur animated frames, with
97	the added advantage of blurring reflections and refractions according
98	to their proper motion.
99	However, this option will result in more noise and expense than using
100	.I pmdblur
101	with
102	.I pinterp
103	as a post-process.
104	If both blurring methods are used, a smaller value should be given to the
105	.I rpict
106	.I \-pm
107	option equal to the shutter speed divided by the number of samples, and the
108	.I \-pd
109	option equal to the aperture divided by the number of samples.
110	This will be just enough to blur the boundaries of the ghosts
111	which may appear using
112	.I pmdblur
113	with a small number of time samples.
114	.PP
115	To simulate a particular camera's aperture, divide the focal length of
116	the lens by the f-number, then convert to the corresponding
117	world coordinate units.
118	For example, if you wish to simulate a 50mm lens at f/2.0 in
119	a scene modeled in meters, then you divide 50mm by 2.0 to get 25mm,
120	which corresponds to an effective aperture of 0.025 meters.
121	.SH EXAMPLES
122	To use
123	.I pinterp
124	to simulate motion blur between two frames of a walk-through
125	animation, where the camera shutter is open for 1/4 of the
126	interframe distance with an aperture of 0.1 world units:
127	.IP "" .2i
128	pmdblur .25 .1 8 fr1023.pic fr1024.pic \| pinterp \-B \-vf fr1023.pic \-x 640 \-y 480
129	fr1023.pic fr1023.zbf fr1024.pic fr1024.zbf > fr1023b.pic
130	.SH AUTHOR
131	Greg Ward
132	.SH "SEE ALSO"
133	pcomb(1), pdfblur(1), pinterp(1), pmblur(1), rcalc(1), rpict(1), vwright(1)