#unwanted camera roll
26 messages in this thread
Does anyone have any tricks for avoiding unwanted camera roll when attempting
near vertical camera angles?
-Loring
Loring,
I ran into this problem a while back. I had an animation focused around a
football stadium. The scene started with the camera directly above the field. I
wanted the camera to drop straight down, and as it neared the field, slowly
take a path around the entire field (point of view always centered on the
middle of the field), then come to rest with great seats on the 50 yard line.
As I started it I noticed if I wasn't careful, it was easy to have sporatic
camera swings, or rolls. Can't tell you why it happens, but my solution was to
make a spline path in the 2D shaper, give it dimension in the lofter, then
import it as a path in the keyframer. Then I set the camera to follow the path
with the camera target sitting constantly on the middle of the field. 3DS did
the rest and I had no more problems.
Hope this helps.
Paul
Loring:
Vertical camera angles will almost give you problems like that. If you are
standing on the North pole, which way is South? <g>
One trick is to rotate your entire scene 90 degrees to make it a horizontal
camera move.
Greg Pyros
>> One trick is to rotate your entire scene 90 degrees to make it a horizontal
camera move.
Wow, then which way is East? <g>
I run into the crazy camera roll problems in virtually every animation I make.
I use an old indian trick: make a camera "roll" keyframe at the point just
before the camera starts to go weird and then every two or three frames after
that (you have to experiment) you must manualy adjust the camera roll (you can
do right in the camera viewport) to get the camera back the way you want it.
It's hard work but it does work.
Alec Jason
Alec,
Sounds like you have good control of your camera roll, but don't you find the
camera shaking at all, as it resists your attempts to curb its own desires…
-Loring
<<. . . as it resists your attempts to curb its own desires>>
Hmm . . . . . I must say that yours is the first message I've received here
which has erotic overtones. Do you also write some of those romance books with
a bare-chested-long-haired-guy-carrying-off-the-young-beauty covers?
I guess to keep in the same spirit of your message:
"In spite of the camera's slow twists and turns, I slowly wrap my hand around
my trackball, feeling its smooth, warm surface as I move it slowly at first,
then faster and faster until I've placed the cursor at what we both know
immediately is the right spot. With my other hand I reach out to the waiting
keyboard as each key beckons me forward. I gently thrust my throbbing finger
down onto the yeilding tab key until it cries out softly and then surrenders to
my will. I look up at the cameraviewport and it looks back at me silently,
sensing my desire and awaiting my command. My fingers are tighter now as they
move with the tracball, first this way and then that way until we become as
one. At last the viewport, in its wild dance to and fro, seems not to loose its
own passion but to accept mine, fully and complete, as it aligns with the
position I have chosen — which is now in harmony with my desire. The camera,
once lost and abandoned is now restrained from motion it did not want nor
choose, waits now, calm, relaxed and fullfilled. "Have no fear," I say softly
as I gaze deeply into the screen, "for Quaternions will not lead you astray
again. I am here."
Anyway, I just keep adding "corrective" roll keyframes until the roll goes
away.
Alec Jason
If you're trying to get us hot, this was a very good attempt. <g>
"…throbbing finger"?
– G
*sheesh!*
-Alan
>> The camera, once lost and abandoned is now restrained from motion it
>> did not want nor choose, waits now, calm, relaxed and fullfilled.
Whew! I think I need a cigarette! <g>
Alec:
I didn't think you had it in you! That one goes into the 'keeper' file! :^)
Greg Pyros
Hey Alex
What kind of a case are you working on these days?!
TedB
!^NavFont01F0006MGHHG|C82C
Gonna upload a few gifs to go along w/ this? <g>
<< Gonna upload a few gifs . . . >>
Don't get me started, Wade!
Alec Jason
hop this "touchy-feely" thread to take-5 please..
Hysterical!
– J
Interactive harlequins! That's it! Forget this flying logo stuff.
-L
<< Interactive Harlequins . . . >>
Hmmmmmm. . . . maybe you're onto to something, Loring.
I could get rid of all this fancy hardware crap and just work with a
comprehensible old typewriter. Well, maybe a 286.
Alec Jason
Are you single? <g>
Michele
>> Are you single? <g> <<
Ahhh. . . no. But I'm very friendly.
Alec Jason
Now that I've seen what you can do with unwanted camera roll, I've got an
unwanted jelly roll here (left over from this morning's meeting) that would
like some attention <BG>. Could be a "sticky" situation.
bob
<< I've got an unwanted jelly roll >>
This falls under the dunkin donuts revision of applied physics. Merely link the
jelly roll to the hand object, and rotate the entire hand object so that it
intersects with the plane of the mouth object. Then assign your path to the
hand object, and the jelly roll object will follow along right to the proper
place. (You might want to adjust the first vertex point of the path so that in
a 3D Display it overlaps the jelly object. This way the jelly roll is sure to
intersect the mouth object cleanly. Forgetting this step will still allow you
place the jelly roll in your mouth, but since there is no collision detection,
you might wind up with your skinned face object smeared with jam.)
-Brian
Shake rattle and roll Shake rattle and roll You can't do nothing to save your
jelly roll.
Michele <this is how my three-year-old niece Natalie sings it)
Occasionally the 3D Studio camera appears to turn everything upside down, as if
the camera has been suddenly flipped 180 degrees. The view in the camera
viewport will suddenly display images that are upside down. The camera does
not have any keyframe information which would explain this flip. The
workaround is simple.
In the keyframer, link everything in your scene to a dummy object on frame 0.
Rotate the dummy object 90 degrees. This will shift the entire animation to an
orientation in which the camera will never be passing over a singularity at the
poles.
Note: This singularity is an artifact of quaternion mathematics, which was
originally developed in the 1800's. All high end animation systems use this
form of math for smooth keyframe motion. Quaternion mathematics is discussed
in John Vince's book, 3D-Computer Animation, published by Addison-Wesley.
Brian, Thanks for the excellent tip. That camera rolling problem has stumped
me more than once. The only other work around I have come up with is to extend
the target point of the camera which minimizes the problem but doesn't make it
go away. Your solution and explanation should be noted in the the manual in
some section called "Exceptions."
.02$ Michael B.
Brian,
Thanks for the history of the polar roll syndrome. A 45 degree rotation gives
me the right angles to get both horizontal and vertical camera views of my
targets without the singularity issue becoming a problem.
-Loring