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## eye point and camera point

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### #1 fir   Members

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Posted 15 June 2014 - 07:51 AM

Do you distinguish this two points? I mean for me camera is a kind of small pyramid that floats in tha air, It has an eye point in rear but in general its centre point (the point around which it can rotate) is not neccesary the same as eye point. I call this two points eye point and camera point though i do not know official terminology for that. could you maybe say something more about this?

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Posted 15 June 2014 - 07:59 AM

No.

### #3cozzie  Members

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Posted 15 June 2014 - 08:06 AM

I just have one (camera position).
What's the exact situation where you need "the other" one? So we can think with you/ share how we would do it

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### #4Samith  Members

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Posted 15 June 2014 - 08:35 AM

Usually the eye point and camera point are the same, and the camera rotates around the eye point. Having the camera point be a point in the center of some arbitrary pyramid isn't very useful. Since the pyramid is just a visualization aid, it makes much more sense for the camera point to be at the tip of the small pyramid. That way your camera/eye point can be the same and nothing needs to change if you change the size of your visualization aid pyramid.

### #5 fir   Members

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Posted 15 June 2014 - 08:38 AM

I just have one (camera position).
What's the exact situation where you need "the other" one? So we can think with you/ share how we would do it

If the camera point is the same as the eye point, rotations is like cloze one eye rotating your head but trying to hold your eye into the same point (so it is rotating your head around your eye)

When camera point is in the the centre of your head rotating your head (camera) effects in moving eye point in space (so its like rotating your eye arond (and out) your head) - this is the case when camera-centre point is behind an eye point ,

you could also imagine that camera centre point can be in forward to the eye point

Edited by fir, 15 June 2014 - 08:44 AM.

### #6 fir   Members

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Posted 15 June 2014 - 08:41 AM

Usually the eye point and camera point are the same, and the camera rotates around the eye point. Having the camera point be a point in the center of some arbitrary pyramid isn't very useful. Since the pyramid is just a visualization aid, it makes much more sense for the camera point to be at the tip of the small pyramid. That way your camera/eye point can be the same and nothing needs to change if you change the size of your visualization aid pyramid.

I do not placed it in the centre of pyramid , sometimes i placed it in the forward scrreen of camera, but it is changable depends what camera I need, (though i didnt do many experimentation with this yet)

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Posted 15 June 2014 - 08:53 AM

I use usally three eyes to render timeline corrected pictures with my special povray 4D renderer.

Because with two eyes I create three dimensional picture, but with three eyes I can create pictures as they have been and will be. You should experiment with such a special renderer.

Edited by Tribad, 15 June 2014 - 08:53 AM.

### #8 fir   Members

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Posted 15 June 2014 - 09:26 AM

I use usally three eyes to render timeline corrected pictures with my special povray 4D renderer.

Because with two eyes I create three dimensional picture, but with three eyes I can create pictures as they have been and will be. You should experiment with such a special renderer.

would need three monitors for that

### #9SeanMiddleditch  Members

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Posted 15 June 2014 - 12:44 PM

Do you distinguish this two points? I mean for me camera is a kind of small pyramid that floats in tha air, It has an eye point in rear but in general its centre point (the point around which it can rotate) is not neccesary the same as eye point. I call this two points eye point and camera point though i do not know official terminology for that. could you maybe say something more about this?

In terms of common terminology, these are the same.

You typically separate the camera from the camera controller. The point you rotate a camera around is determined and handled by the camera controller, not the camera. The camera has an eye position, view vector, and up vector (or some other data that is equivalent). The camera controller might have a position, distance, euler angles, zoom factor, rotational speeds, etc. (The presence of a zoom factor means that the camera controller also affects the projection matrix and FOV and not just the camera matrix).

Some engines conflate "camera" with other things like filters and render modes and post-processing settings. In such engines, you tell a "camera" to render and then it figures out what and how to do the rendering, but a separate camera controller still generally deals with moving the camera. In terms of the usual engine-agnostic terminology, the camera is just the base mathematical definition needed to construct a camera matrix, and everything else is part of the scene render pipeline or game logic.

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### #10 fir   Members

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Posted 15 June 2014 - 01:06 PM

Do you distinguish this two points? I mean for me camera is a kind of small pyramid that floats in tha air, It has an eye point in rear but in general its centre point (the point around which it can rotate) is not neccesary the same as eye point. I call this two points eye point and camera point though i do not know official terminology for that. could you maybe say something more about this?

In terms of common terminology, these are the same.

You typically separate the camera from the camera controller. The point you rotate a camera around is determined and handled by the camera controller, not the camera. The camera has an eye position, view vector, and up vector (or some other data that is equivalent). The camera controller might have a position, distance, euler angles, zoom factor, rotational speeds, etc. (The presence of a zoom factor means that the camera controller also affects the projection matrix and FOV and not just the camera matrix).

Some engines conflate "camera" with other things like filters and render modes and post-processing settings. In such engines, you tell a "camera" to render and then it figures out what and how to do the rendering, but a separate camera controller still generally deals with moving the camera. In terms of the usual engine-agnostic terminology, the camera is just the base mathematical definition needed to construct a camera matrix, and everything else is part of the scene render pipeline or game logic.

i also had such a division - i named it 'camera navigator', though still there are some points for count the point of rotation as a camera properity not navigator - one (maybe main) is this that rotating camera around some point external of the canera eye is not more mathematicaly external to the camera as rotating it around the eye;

but somewhat youre right there is need for camera navigator and this second point you can delegate there if you want

### #11Hodgman  Moderators

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Posted 15 June 2014 - 04:09 PM

After working on a game where the artists have set up cutscenes with a <1deg FOV, and then moved the camera 100m backwards, and moved the near-clip plane 100m forwards... I would really like there to be a distinction. In that situation in makes much more sense to say that the camera's lens is located at the location of the near plane. The 'eye position' is then just a mathematical device to make the math work out.

### #12 fir   Members

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Posted 15 June 2014 - 05:01 PM

After working on a game where the artists have set up cutscenes with a <1deg FOV, and then moved the camera 100m backwards, and moved the near-clip plane 100m forwards... I would really like there to be a distinction. In that situation in makes much more sense to say that the camera's lens is located at the location of the near plane. The 'eye position' is then just a mathematical device to make the math work out.

Near plane IMo as i said in other thread seem to me is not real object to say about but only the thing that is used to make geometry clipping faster at a cost of bad artifacts of cutting the near scenery - in full triangle frustrum clipping near plane do not hopefully exist (there is no such thing as near plane in correct projestion)

camera point is other thing just when i have 6 function for moving the camera

- left

- up

- forward

- yaw

-pitch

-roll

when defining camera point as a subject of those six operation,

It is more valuable to hold him as not neccessary the same as eye point but ingeneral with some offset you chose ) that makes camera steering options "wider"

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