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Dalaran AW
05-26-2004, 11:39 AM
Hello there,

I was planning to model my first human head in maya. So I took the first step by photographing a friend face from front and side. But something weird occured.

I am trying to align these photo's in photoshop... so they match in scale... so I can bring them proper to use them as image planes. But somehow I cant get them aligned and correctly scaled... If I got 1 facial feature correct the other one is incorrect.

Is there something wrong with the camera settings? Or am I doing something wrong. If have tried to photograph my brother after this strange thing... but the samething occured... does anybody had the same problem?

Greetz,
Dalaran AW

http://home.planet.nl/~verh2976/private_cg/scale.jpg

azazel
05-26-2004, 12:33 PM
it's not easy to get these photos exactly 'straight', camera could have been tilted, or not on the same level, also, focal length matters - the longer the better ('flatter' photos)

Dalaran AW
05-26-2004, 12:37 PM
Hello Azazel...

thanks for your reply...

So your recommending.. shoot from a far distance and use a tripod... right?

Dalaran AW

mercuryrex
05-26-2004, 06:49 PM
Yes, I have this problem quite a lot.

It usually takes a lot of time tweaking things by rotating and resizing to get things right.

From the example you have provided, this will hopefully work:

Rotate the side profile photo a couple of degrees clockwise from the CENTRE OF HIS IRIS.
Hopefully you should get a better match.

In future photographs, try to make sure that the person is looking at you absolutely straight on.
If he's looking slightly up or down, it's not a complete disaster, but it would mean that you would have a harder time modelling the head while making it actually look like your subject. You wouldn't be able to model with his head straight, you'd need to model to adjust for the head tilt.
The bottom of his nostrils should align with the bottom of his earlobes.
If your front profile image is looking absolutely straight on, it's an easier job to match the side view to the front view if the side view is okay.

If you have a bad picture to work with that obviously has too much lens distortion, I have found that it can be corrected to some extent in Photoshop by selecting just inside the head area with the pen tool, then using a negative value with the spherize filter.
Values of between -12 and -20 seem to sort things out.
If you're careful, you can get the photo to "pop" into more realistic proportions.

Also, make sure that your subject doesn't tilt his head to his right or left side in the side profile photo. NOT EVEN A LITTLE BIT.
This will make his facial proportions vertically smaller or taller, depending on which way his head is tilting.
Tilted up or down isn't a problem in a side photo, but a sideways tilt would be.
This would be even worse than your subject looking up or down in the front view, and it would be a nightmare to get things to match in that instance.
You can usually work around any slight head tilt in the front view, but a bad side view is almost unusable. It would be too much work to try and figure out what the true side profile would normally look like. As modelling reference it would probably be useless and you might as well guess.
For a side photo you really could do with a third person checking that the subject's head is absolutely straight, it's not something that you or your subject will be able to tell.
Your subject just wouldn't know, and you taking the photograph just wouldn't be able to see from the view you are taking the side photograph.

Hope some of this is useful.

I'm looking at the photos, and although the proportions are close, for some reason the side view photograph seems much bigger. I suspect that there was a bit of sideways tilt going on there, so you compensated by needing to zoom in to get the proportion of his features to match somewhat.

Don't forget, rotate your side view using his pupil as the centre of rotation. I think you'll get a bit closer if you do that.

Dalaran AW
05-26-2004, 08:25 PM
mercuryrex...

thanks a lot for your effort... and this information is very helpfull. I am going to shoot new pictures right away according to your guidelines. Indeed al these point you mention seem pretty obvious when you hear them...

Thanx... :buttrock:

Dalaran AW

mercuryrex
05-26-2004, 10:37 PM
You're welcome Dalaran:)

I understand what you're going through. I've had exactly the same problems before that you are having right now.

I wish those points were obvious when I started doing what you're doing.;)
I reckoned I knew what I was doing, but the truth is that there was a lot of things that could go wrong that I didn't anticipate.
It took a lot of trial and eror before I realised what things I may have been doing wrong.
Such as making the mistake that if the camera is to close to the subject, you get a distorted bulbous nose, then I learned that you need to have some zoom on the camera to flatten the image out properly.

And like azazel said, sometimes diferent photos aren't taken with the camera at the same level, which can produce the same problems as if the head was tilted.

I'm still learning how to do things the best way I can. So I myself would very much appreciate any observations you make while doing this, so as I can possibly learn something new.
I'm glad you started this thread as I am hoping that some experienced people here can provide a lot of valuable information regarding the preparation of images for realistic head modelling that I can benefit from too.

So let me know how you get on will you?
:)

peanut
05-27-2004, 04:41 AM
try to avarage your geometry, and not just rely on a ref

Dalaran AW
05-27-2004, 10:43 AM
Hello...

peanut > Thats a good point... but I think it would get me even more in trouble if I rely on bad reference... And because this is one of my first serieus heads... I dont have the good skill to "freestyle" a head together... :) I wish I could...:D

I have shot today some new picture according to some of mercuryrex's guidelines... and I think this one is much better then the ones before...

Greetz,
Dalaran AW

http://home.planet.nl/~verh2976/private_cg/darren_ref.jpg

peanut
05-29-2004, 11:35 PM
I think there's a tool in Photoshop that lets you change the angle of pictures/textures and even flatten them.

CaLvin_K
05-30-2004, 09:02 AM
If you want, you can adjust all the settings needed in maya...

this (http://www.gnomononline.com/tutorial.php?category_id=2) tutorial is great.

number9
05-30-2004, 02:11 PM
I think it's because of the lens you are using for your camera.
Ideally, you would want to have an ortographic image as reference, but that doesn't exist in the natural world. So if you have for example a 35mm wideangle lens, the picture will get deformed, the features in the face will become bigger, the nearer the camera they are.
The best way to take referencepictures would be to use a telelens. Something like 100 mm + would probably be good.

I had the same proboblem as you for a long time, but nowadays, I always try to draw my refernce by hand. Then I'll get exact proportions, but ofcourse, it requiers alot of practice to do it well.

Hope this helped you some. :)

Nolita
06-06-2004, 03:28 AM
I'm a total newbie to 3d. That is to say, I follow some simple tutorials, where the person swears it took them just an hour or two, then it takes me one or two days to complete, and I feel like a total moron for even trying and get discouraged, and quit for awhile then try again later(bad habit I'm sure).

Still I was thinking that if you decide to learn the basics of portraiture, you could easily just draw your references. By using horizontal lines, you would allways end up with perfectly proportional pics that would allways match. I know that Polykarbon.com has some tutorials for basic drawing, mind you they are based on anime, but they're really easy to follow(I believe that's due in part to the fact that the site appeals to almost all ages, so they couldn't be so complex that a six year old couldn't follow along, or so simple that a seventeen year old would get bored).

By simply googling phrases like free tutorials for drawing, you will find a ton of sites with information on how to draw portraits, as well as the human figure and clothing.

Really I think it's a good idea to learn how to draw, and get yourself a color wheel and learn about complimentary colors. To someone who draws the reasons are probably obvious. However I'm assuming you have little experience with drawing.

Basically, if you can draw, you don't need photos to create a character. Therefore you can create whatever and whoever decides to populate your imagination and subconcious...that would be especially good and handy if you decide to become an animator or game designer and create your own worlds. The reason for the color wheel and learning a bit about color theory is that you won't end up with clashing colors. Also it will free up your creative side even more, because you will be much less limited, that is to say, if you have characters, where one side is good and the other evil, you won't be forced to simply have good be dressed in white, and evil be dressed in black. Example you could have good dressed in forest green and evil dressed in a shade of purple, as those two colors are complimentary.

It's all so much easier to show and learn, than to explain.

Anyway good luck to you.

Dalaran AW
06-07-2004, 10:45 AM
He Nolita...

Well that discouriging nature of you... has a lot of similarity's with mine... ;) I know excactly what youre going throught...:scream:

But for the drawing aspect you guys are right... I have experience with drawing.. but somehow always what I have in my head I cant get on paper... I am not that skilled with pencil, that my ideas can take physical forms on paper... I am already modeling a head know from this photorferences... but when I am finished with this one... i will indeed surely try to draw my own character and try to model it...

Greetz,
Dalaran AW

StephanD
06-07-2004, 11:01 AM
On what count were those two guys arrested? ;)

mercuryrex
06-07-2004, 10:54 PM
Nolita,

The thing with drawing your references, is that sometimes people want to do photorealistic humans.

The person who started this thread wanted to create a 3D representation of his friend.

No amount of drawing is going to enable him to do that, or he would have to be an incredibly skilled atrist to get anywhere close.

Non photorealistism has it's place,....but so does photorealistism.
And I think photorealism is what the main focus of this thread is leaning towards.
I think most people in this thread want to nail the problem of getting photogrpahs perfect for the modelling process.

I see many NPR topics, but I don't often see threads like this that concentrate on mainly on getting photo reference images perfect in the aim of creating photorealistic humans.

But thanks for the ideas about drawing. I've seen some of the tutorials you mention and they are very good.
But I don't think the drawing side of things is applicable in Dalaran's needs, although it is very useful in other projects.

IestynRoberts
01-06-2006, 10:16 PM
Thanks a lot for starting this thread, it's just exactly what i was looking for, thanks a lot for your reply mercuryrex. Im gonna have a play around now.
-Iest

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