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Subject: 
Re: Tilting the camera
Newsgroups: 
lugnet.cad.ray
Date: 
Mon, 27 May 2002 13:57:33 GMT
Viewed: 
653 times
  
"Lars C. Hassing" <lch@ccieurope.com> skrev i meddelandet
news:Gwqr3t.L63@lugnet.com...
Travis Cobbs wrote...
In lugnet.cad.ray, Don Heyse writes:
Sproat called it Roll in his tutorial.

That's what I would call it.

I noticed Sproat calls it roll: "How to roll the camera", but he also • says:
"I'm really talking about tilting the camera to one side."
And to me (being a non-English-native) roll is more ambiguous than tilt.
[...]
I would think this would be pitch.  (Yaw would be left/right.)

Yaw ? You said you would call it roll ?


I can imagine 'tilting' or 'slanting' both sideways and forwards/backwards.

ROLL, PITCH and YAW are unambiguous.

Imagine the camera sitting in the cockpit of a plane, looking forward, then

ROLL  - the rotation around the axis 'tail <--> nose'
PITCH - rotation around the axis 'right wing <--> left wing'
YAW   - rotation around the third axis (like turning your head)

and CCW being the positive direction.

Your problems with the sky vector may be the fact that sky implies a ROLL
and this ROLL is applied _first_ to match the camera and the sky vector,
then look_at changes the YAW, and finally the PITCH (at least that's my
interpretation of the POV documentation).

Modifying both SKY and RIGHT seems to do the job for me:

#declare TiltAngle = 30
#declare CameraRoll = -TiltAngle*pi/180  // '-' to get CCW for positive
angles

sky      -y*cos(CameraRoll) - 4/3*x*sin(CameraRoll)
right    -4/3*x*cos(CameraRoll) - y*sin(CameraRoll)

--
Anders Isaksson, Sweden
BlockCAD:  http://user.tninet.se/~hbh828t/proglego.htm
Gallery:   http://user.tninet.se/~hbh828t/gallery/index.htm



Message has 1 Reply:
  Re: Tilting the camera
 
(...) Thanks, I guess it's ROLL then. (...) Hm, first vote for CCW. Why? (...) I agree, see also (URL) Modifying both SKY and RIGHT seems to do the job for me: (...) Nope, sorry - it doesn't work if you look at the model from +x, e.g. with -cg30,90 (...) (22 years ago, 30-May-02, to lugnet.cad.ray)

Message is in Reply To:
  Re: Tilting the camera
 
Travis Cobbs wrote... (...) I noticed Sproat calls it roll: "How to roll the camera", but he also says: "I'm really talking about tilting the camera to one side." And to me (being a non-English-native) roll is more ambiguous than tilt. Anyone else ? (...) (22 years ago, 26-May-02, to lugnet.cad.ray)

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