man/man1/pmdblur.1

.\" RCSid "$Id: pmdblur.1,v 1.1 2005/01/18 03:59:40 greg Exp $"
.TH PMDBLUR 1 1/17/05 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:	1.2
Committed:	Tue Jan 18 20:19:56 2005 UTC (19 years, 3 months ago) by greg
Branch:	MAIN
CVS Tags:	rad3R7P2, rad3R7P1, rad3R8
Changes since 1.1:	+8 -1 lines
Log Message:	Added example aperture calculation
#	Content
1	.\" RCSid "$Id: pmdblur.1,v 1.1 2005/01/18 03:59:40 greg Exp $"
2	.TH PMDBLUR 1 1/17/05 NAME
3	pmdblur - generate views for combined camera motion and depth blurring
4	.SH SYNOPSIS
5	.B pmdblur
6	.B speed
7	.B aperture
8	.B nsamp
9	.B v0file
10	.B v1file
11	.SH DESCRIPTION
12	.I Pmdblur
13	takes two viewfiles and generates
14	.I nsamp
15	views starting from
16	.I v0file
17	and moving towards
18	.I v1file,
19	simulating an aperture of diameter
20	.I aperture
21	in world coordinate units.
22	When rendered and averaged together, these views will result in
23	a picture with motion and depth-of-field
24	blur due to a camera changing from v0 to v1
25	in a relative time unit of 1, whose shutter is open starting at v0 for
26	.I speed
27	of these time units.
28	Either
29	.I pinterp(1)
30	or
31	.I rpict(1)
32	may be called to do the actual work.
33	(The given
34	.I v0file
35	must also be passed on the command line to the chosen renderer, since
36	.I pmdblur
37	provides supplemental view specifications only.)\0
38	.PP
39	For
40	.I pinterp,
41	feed the output of
42	.I pmdblur
43	to the standard input of
44	.I pinterp
45	and apply the
46	.I \-B
47	option to blur views together.
48	In most cases, two pictures with z-buffers at v0 and v1 will
49	get a satisfactory result, though the perfectionist may wish to
50	apply the
51	.I \-ff
52	option together with the
53	.I \-fr
54	option of
55	.I pinterp.
56	.PP
57	To use
58	.I pmdblur
59	with
60	.I rpict,
61	apply the
62	.I \-S
63	option to indicate a rendering sequence, and set the
64	.I \-o
65	option with a formatted file name to save multiple output
66	pictures.
67	When all the renderings are finished, combine them with the
68	.I pcomb(1)
69	program, using appropriate scalefactors to achieve an average.
70	Note that using
71	.I rpict
72	is MUCH more expensive than using
73	.I pinterp,
74	and it is only recommended if the scene and application
75	absolutely demand it (e.g. there is prominent refraction that
76	must be modeled accurately).
77	.PP
78	For both
79	.I pinterp
80	and
81	.I rpict,
82	the computation time will be proportional to the number of views from
83	.I pmdblur.
84	We have found a
85	.I nsamp
86	setting somewhere between 7 and 15 to be adequate for most images.
87	Relatively larger values are appropriate for faster camera motion.
88	.PP
89	The
90	.I \-pm
91	and/or
92	.I \-pd
93	options of
94	.I rpict
95	may be used instead or in combination to blur animated frames, with
96	the added advantage of blurring reflections and refractions according
97	to their proper motion.
98	However, this option will result in more noise and expense than using
99	.I pmdblur
100	with
101	.I pinterp
102	as a post-process.
103	If both blurring methods are used, a smaller value should be given to the
104	.I rpict
105	.I \-pm
106	option equal to the shutter speed divided by the number of samples, and the
107	.I \-pd
108	option equal to the aperture divided by the number of samples.
109	This will be just enough to blur the boundaries of the ghosts
110	which may appear using
111	.I pmdblur
112	with a small number of time samples.
113	.PP
114	To simulate a particular camera's aperture, divide the focal length of
115	the lens by the f-number, then convert to the corresponding
116	world coordinate units.
117	For example, if you wish to simulate a 50mm lens at f/2.0 in
118	a scene modeled in meters, then you divide 50mm by 2.0 to get 25mm,
119	which corresponds to an effective aperture of 0.025 meters.
120	.SH EXAMPLES
121	To use
122	.I pinterp
123	to simulate motion blur between two frames of a walk-through
124	animation, where the camera shutter is open for 1/4 of the
125	interframe distance with an aperture of 0.1 world units:
126	.IP "" .2i
127	pmdblur .25 .1 8 fr1023.pic fr1024.pic \| pinterp -B -vf fr1023.pic -x 640 -y 480
128	fr1023.pic fr1023.zbf fr1024.pic fr1024.zbf > fr1023b.pic
129	.SH AUTHOR
130	Greg Ward
131	.SH "SEE ALSO"
132	pcomb(1), pdfblur(1), pinterp(1), pmblur(1), rcalc(1), rpict(1), vwright(1)