PDA

View Full Version : view distance


El_Schubi
06-27-2003, 02:17 AM
hello,
i have a.. problem with perspective in max. so the problem is not really 3ds max, and i'm also not sure about how to specify it.
to describe it:
i'm about to create a 3d character in 3dsmax. during modeling i often use the perspective viewport to decide if a proportion is correct or not. now the raw modeling ist complete and i'm working on the final look of the face. now something happened i don't know how to fix or even why it happens.
the problem is i rendered my caracter out of perspective view.
when i'm sitting directly in front of my screen (eye distance 30cm or shorter) the face looks as i want it. but when i'm moving away from the screen maybe 1 meter the face does some kind of deforming or stretching, anyway, it changes and that's something i don't want. the altering process starts when i'm more than 30cm away from my screen.
ok, so i think it is something concerning perspective. so i think i have to use a camera, tested it, but the deforming happened again. of course i know images which are painted in perspective and do some kind of movement if you're altering your position watching them.
so to avoid this problem and have a camera setting which prevents this "optical phenomenon", how should i set up my camera (lens diameter?). i've a camcorder with a 72mm lens. is this a good value?
what kind of lenses are used in cinema movies, or for professional portrait photographs?
maybe anyone knows a website explainen this effect, because i don't know how to make the search engine understand what i want :D
of course you are free to explain this effect to me if you know something about it, or how to avoid it :beer:

thx in advance

el


edit: i forgot, the same thing happens when i load the image in photoshop and zoom in or out without altering the eye distance to the monitor. zooming out means deforming and zooming in...

Dave Black
06-27-2003, 04:55 AM
When you say it "stretchs", "alters", and "deforms", can you be more specific?

I mean, the image on your screen should'nt change when you move in and out from your screen. It sounds like a hardware or crazy person issue. ;)

What type of monitor are you using, etc. etc.

Don't get me wrong, you could just be crazy.

-3DZ

:D

El_Schubi
06-27-2003, 12:02 PM
hm, to be more specific:
you know painted images with a vanishing point. when you're standing in front of them and move to the left or to the right, the image seem to change, and align to your view.
i think i also have some kind of this problem. so i'm not changing my image, it is rendered and open on my screen. i do no digital zooming or something else on the monitor. i simply change the distance of my chair to the monitor. and the more i move myself away the more the image changes. i think this happens, because i have a very strong perspective in my image. so im looking for camera settings to avoid these distance changing effects.

and other persons have the same "problem" with that image so maybe i'm not crazy :D

golem
06-27-2003, 12:12 PM
just use a camera. if u use perspective view and zoom out you can easly be envolved in a lens view under 9mm.
put a camera in front of your model, always set it at 50 or 35mm and if you want to get a larger part of the model right click on "move tool" and set a different distance on the dolly panel.
maybe useful?

golem

mouj
06-27-2003, 12:14 PM
I would second 3DZ here, it's probably a hardware issue, else i don't really see how this could happen; i mean of course if you change your point of view, then you don't see things the same way, but then again you're talking about an image, a still; unless you've managed some incredible effect on it, i don't see how it would change so dramatically from you just looking at it from a further distance.

I do agree to the fact that some compositions stand out better from a certain distance, but again, it does not distorts the comp itself.

Is your monitor having problems ? Are you using a laptop or something ? :p

mouj

El_Schubi
06-28-2003, 02:42 AM
i talked to an artist today, no cg artist!
he told me that if an image looks right to me from greater distance, it will also look right from a short distance. vice versa this is not granted. so maybe there is the problem. i modeled the face with a 30cm distance from the screen.
to avoid it in the future, i maybe should move the screen farer away.
and no, it is definitly no hardware problem, i must have modelled by accident a face with enormous optical deception.

Schnupps
06-28-2003, 03:10 AM
Man, this something for Scully and Mulder...
Maybe youīve bought a 4dvisiont ft panel without knowing ;-) ?
Actually I canīt believe it, except itīs an crazy monitor issue.

But I want to believe! Canīt you upload this image?

Schnupps

Dave Black
06-28-2003, 03:12 AM
That is horse poo.

You can't do that. Your screen is a 2d projection of an image. It will not change like that if you move away from it the screen. Period.

I am guessing that you adjusted the FOV of your camera without noticing.

-3DZ

:D

grury
06-28-2003, 03:55 AM
hummmm???.. Fantastic....to say the least.:surprised

mouj
06-28-2003, 10:47 AM
So do you really think moving your screen further or closer will improve your modeling ? :rolleyes:
(btw, you'd rather move your head than your screen, don't you think ?)

mouj

El_Schubi
06-28-2003, 02:12 PM
so here is the image (sry, that i had to reduce the quality so dramatically).
so it has no textures and modelling is not complete (also hair is in a pretty early stage ;)

i'm thinking, that the "distance effect" may rely on the fact, that modeling of the part directly below the eyes is not complete, yet.

but, watch it from a 30cm distance or shorter and than move back, you will notice some kind of altering in the face.

Aldaryn
06-28-2003, 04:15 PM
Man, this is wierd...
I've looked at the image from 30cm, and again from 1m, and from 2m... And I haven't noticed any change....
To be correct: I'm using a standard 2D monitor, with a flat screen.
Maybe you've got dome superfly hardver of sort... I don't know...

Normally, your modell shouldn't change in topology (assuming it is not animated) due to the view angle, and FOV...
Man this is wierd... totally wierd.

My most basic problem with your problem, is that you're modelling, and not painting! You're modelling in 3D, so the whole modelling and rendering process separates. What you modell, stays that way, keeps it's shape unless you change it manually, or face a serious software problem....

The output of your model, the rendering is a totally 2D matrix of pixels, and unless you have some really starange monitor, the pixels are displayed on a flat surface. So no 3D effects can appear....

Wow, I really don't know what to say. Have you considered to see a medium? :) Just kiddin'...
Maybe this image carries some strange curse or somethin'...
I'm starting to get scared... I've looked at it. Brrr... It's really getting cold, or it's just me?.....

grury
06-28-2003, 05:22 PM
...I could swear I saw it wink at me ;)

heavyness
06-28-2003, 05:45 PM
do you have one of those video cards that can do "3D" if you plug special glasses in? you might have that settings turned on by default. if that's not the case, i don't know...

El_Schubi
06-28-2003, 06:23 PM
hm, so maybe it'S really the monitor ;)
it is just a standart monitor, not even a flat one.
i asked 2 other persons and they told me they see a slight changing in the image depending on distance.
so it's no superfly hardware i have, but some i should buy ;)

magicm
06-28-2003, 06:55 PM
Unless you've eaten a curtain type of mushroom :surprised, the shape of a flat image does NOT change when viewed from different distances.

- Martijn

Aldaryn
06-28-2003, 07:08 PM
Maybe you and your friens should stop watching this picture....
Trust me, some odd things happened since I've looked at it... ;)

(...)

The monitor can be the source of your problem. Old monitors, or non-flat monitors, mostly old, non flat monitors can distort the image, if not viewed form direcly front. Or you just have to adjust the distortion settings of your monitor.

Beats me... :shrug:

El_Schubi
06-28-2003, 07:12 PM
i never talked about the shape, but about optical deception caused by shadows and contrast.
with these two "parameters" an image can alter in some way. eyes for example can look bigger, cheeks may move or grow a bit.
these are the changings i'm referring to.
but at first, i have to check my monitor maybe it is not as good as it should be...

Aldaryn
06-28-2003, 07:40 PM
Well, ok. The colors can alter the image a bit, but these modification eg. a thin blak outline around the eye makes it look bigger, or black around the nose sharpens it a bit. But this is "permanent", it still won't be affected by the view angle.
Some images are composed to be more, than a single view creation, with a composition adapting to the viewer. But this still won't affect the shapes, or colors, this will only "recompose" the composition of the image, so it vill remain it's composition concept through a wider angle.

Man, this problem is the wierdest ever! ;)

Hope you've get to the cause really soon... Good luck!

celticdog
06-29-2003, 11:16 AM
I think I might know whats going on. The shading/lighting of your character is strange. The face is darker than the neck and shoulders. Dark tends to recede and light comes forward in images. I did notice that this effect is more obvious when you look at it from a distance. Seeing as how its your art and you're probably looking at it much more intensely than most of us, its probably playing tricks on your eyes.

NRat
06-29-2003, 11:43 AM
Can you upload 2 captured images from your camera, one from 30 cm, and ane from ~1m? ;)

El_Schubi
06-29-2003, 02:32 PM
@celticdog: yes, you may have hit it. there is only one omnilight in the scene. and this is only because shag:hair needs it.
in the modeling stage i normally don't worry about lighting. so this maybe explains, why it tends to me that the cheeks move down a bit with growing distance to the image.
as i've been to a drawing school for one year i know about bringing depth to images by contrast and darker or lighter colors.
so maybe i've become sensitive to that.
the problem is also that i'm very "special" with faces. they have to have a certain look to appeal to me. as i'm creating a 3d character it obviously should appeal to me :)
and with this one (so ok it's my first one) i have the problem: from a 30cm distance it looks more or less what i want, but as i move away it changes to a look that does not appeal to me.
i know that it is only about very little changings but it's more than i'm willing to accept ;)
so the next thing i'll try is creating a proper light setup with gi or something, maybe this will solve something. and i'll also contact one a lot more experienced artist than me who can analyse this image and explain some optical problems it contains.

NRat
06-29-2003, 02:50 PM
Maybe the problem is in you, not in hardware or software? :rolleyes:

CGTalk Moderation
01-15-2006, 12:00 PM
This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.