should I sculpt heads in perspective view?

omid3098

usually I sculpt heads (almost every sculptural object) in orthographic view in ZBrush. but most of times, the final in-game character will not look like original concept, even if highpoly model was exactly same as concept. I think that is because of difference between orthographic and perspective view. am I right?
head concepts are usually a perspective view of a character and when I sculpt a perspective concept, in an orthographic view, it will be wrong when I look at it, in perspective view. (I think!)
this is my final sculpt in ZBrush:




and this one is his lowpoly and perspective shot in 3ds max (FOV=70):



now he is another guy!

did you have any similar problems with in-game characters?
and do you sculpt characters in orthographic views or in perspective?

(and such a stupid question: when I add images as attachment and put them in my posts, it will show a link, not my attached images. why?! :poly136: )

Muzzoid

Yes sculpt in perspective.

Its more like how you will see it in the final game/movie, so is more relevant.

haikai

I totally understand the argument for working in a view that more closely resembles the game camera, but a good head model is going to have the same dimensions in space regardless of what angle of view you're looking at it in. It probably depends on what you're more comfortable with.

I think it can be useful to work in both views. It's good to switch to perspective view once in a while to check on things, but having a lot of perspective, especially when working on a head, can be disconcerting. A lot of portrait photography is taken with more telephoto ranges to reduce unflattering distortions of the face, and trying to mimic that when modeling can make it easier to judge forms (for me).

Does the head model in Max look better when you zoom out and view it from a distance?

chrisradsby

I use the have that problem as well, but it was before I knew that you could change to perspective in Zbrush, now I only sculpt in perspective since it's more like the end result. If your model does not look like it should even in perspective view in a 3d-package you might want to mess around with the perspective view and change the FOV.

omid3098

thank you guys.

haikai wrote: »

Does the head model in Max look better when you zoom out and view it from a distance?

yes, it will be better but still he is another guy!

it's little strange to sculpt in perspective view in Zbrush! "F" will not fit model to view, camera will not rotarte around my last sculptes area...
now I'm tring to get same FOV as max in zbrush. differe between 0-180 in focal angle will not affect much on my model, but it will affect much in ZBrush deffault models! (rihno or dog) *shrug*

omid3098

ok.
I found how should I mach ZBrush FOV with 3ds max.
the point is to put your model in global 0,0,0 and then use it to ZBrush. (I used GoZ for this)
and as your model is far from 0,0,0 the perspective strenght will be reduce.
no matter how big is model, FOV just depends on posotion.
shots are with 70 FOV and last one is orthograph mode:

cryrid

I say always sculpt in perspective. Orthographic may come in handy for making straight selections or masks, but beyond that it is a view we just don't see with out own eyes. Perspective and foreshortening exist. Turning perspective on should not affect the ability to fit an object with F or rotate around the last touched vert (assuming local transformations is turned on)

omid3098

yes. now I'm more comfortable with perspective sculpting. and after I moved model to 0,0,0 there is no more problems with "F" and local rotation!
everything works fine.
thank you all.

MoP

Yeah, I find that sculpting in a non-perspective view gives you a very misleading result.

Bear in mind that if you're using photo reference, the camera may have a different field-of-view, so having a "high" perspective distortion setting in ZBrush may actually work against you in some cases, if you're trying to match a photo.

However, using straight orthographic view when working from references tends to lead to wonky proportions, in my experience (not just from me sculpting, but from seeing other people sculpting in ortho views too).
The only time I really use ortho views in ZBrush is to do precise axial moves/scaling or transpose positioning.

omid3098

perspective distortion in zbrush do not change by object distance from camera. while in 3ds max less distance will cause more distortion. I don't know much about camera lens. but using a camera in 3ds max, we can convert each lens to FOV value, use same value in zbrush and compare all of them them (max, zbrush and concept) in almost same distance from camera.
it was wrong habit to sculpt in orthographic view..

chakkrit

This is exactly the thread I needed! I'm working on a head sculpt and I've always used the ortho view in ZBrush because I've never been told otherwise. But now, coming to think of it, some models I've produced in the past have turned out worse than others which is probably why I didn't notice it too much. Lesson learnt. I'm gonna use the perspective from now on. Thank you to all the previous posts for your insight - I just hope my photo reference still line up more or less...

Frankie

This image is pretty cool to see

http://www.lesjones.com/www/images/posts/stepheneastwood-tile1.jpg

Ace-Angel

So a good question is, what FOV would be the most 'natural' in terms of real world volume and number to sculpt in?

This is something I always struggles with, even with games...

gilesruscoe

I think i read somewhere a long time ago that 35 was the most natural for things like faces, can't remember where/how valid that source is though. Would be an interesting experiment.

[HP]

It depends really, it even depends on the app your modeling in, or what editor you're trying your shit out. But I found that when working with assets, textures and materials, using a narrower FoV is much much better, it gets you closer to the details and it's more focused somehow. I tend to stick with a FoV around 40'ish.

artquest

My teacher once told me that a focal length of 55-60ish resembles what the human eye sees in perspective. So I try to sculpt/model using that.

I also have tried to sculpt in ortho mode in zbrush but I always find that because our eyes are used to seeing in perspective I would try to force perspective on the model without even realizing it. Resulting in a very strange looking head when I finally did put it in perspective.

gilesruscoe wrote: »

I think i read somewhere a long time ago that 35 was the most natural for things like faces, can't remember where/how valid that source is though. Would be an interesting experiment.

This seems to make sense to me because a focal length of 35mm is (I think?) a very common focal length in cameras. since we're used to seeing portrait photos taken with a 35mm lens it seems natural to use that when we render. After all it's still called a "camera" in CG even if it's in a game or in a 3D app

Just remember not to place the camera too close to your character though, as you can see in the picture frankie posted, the closer you are to your object the more distortion you will get.

Neox

MoP wrote: »

Yeah, I find that sculpting in a non-perspective view gives you a very misleading result.

Bear in mind that if you're using photo reference, the camera may have a different field-of-view, so having a "high" perspective distortion setting in ZBrush may actually work against you in some cases, if you're trying to match a photo.

However, using straight orthographic view when working from references tends to lead to wonky proportions, in my experience (not just from me sculpting, but from seeing other people sculpting in ortho views too).
The only time I really use ortho views in ZBrush is to do precise axial moves/scaling or transpose positioning.

also keep in mind to check your model every now and then in a real 3d package, as zBrush doesn't have a real perspective, everything can break once you move it into an actual 3d app. This can get pretty annoying when doing likeness.
for presentation, it's always nice to use a lens photographers use for portraits, which is usually (take this with a grain of salt) 85mm and higher.

chakkrit

I'm not sure if anyone has done any reading around this subject at all but I've found these links...

artquest has the right idea I think. The general consensus seems to be the human eye focal length is roughly 17-50mm. So I'd say aim for around the 35mm mark. Best thing to do is regularly check the model in your engine/3d package of choice as well.

http://www.photofidelity.com/blog/50mm-eye-fov-busted.html

http://www.clarkvision.com/articles/eye-resolution.html

http://hypertextbook.com/facts/2002/JuliaKhutoretskaya.shtml

Elyaradine

In terms of the way real perspective works in a camera/lens, you actually need to combine the use of lens (wide angle vs. telephoto) with distance from the subject in order to achieve the look you want (there are other factors too, but I think they're not relevant here). If your distance to the subject stays constant, wide angle lenses have a more exaggerated perspective, while a telephoto lenses flatten your image. If your lens stays constant, then moving toward the subject exaggerates perspective, and moving away flattens it. (If you're further away, the subject will of course appear smaller too; but if you take the photo from far away, and upscale it to be the same size as a photo of the subject from close up, using the same focal length, you'll see they have different amounts of perspective distortion.) Your eyes swap focal length depending on whether you're viewing something far away or close up.

So what can we take away from the above?

* Don't get too close to your sculpt, because if you're using perspective, it'll get way more distorted, and you won't be able to trust your eyes to judge forms any more. (Traditional sculptors step a few metres away from their sculpt, regularly, to get a truer sense of what their sculpts look like. Surely we can learn from them!) :thumbup:

* The perspective distortion applied to a model is going to change a lot (depending on the game). In a FPS, if she's standing right next to you, she'll have more perspective distortion than if she's standing several metres away, without having changed your camera's focal length/FOV. In this case, sculpting in perspective "just because it'll be in perspective in the game" just doesn't make sense in my opinion. Clearly, even within perspective views, things can change a lot. Where this does make sense is in games where the camera's a fixed focal length and fixed distance from your targets, like in most strategy games -- you can then model/sculpt to match the camera -- but then they usually seem to use ortho cameras anyway.

* If you're taking a screengrab/render of your sculpt, a noob mistake is to fill your frame with your head, to try and show as much of the head as possible. This is the equivalent to stepping right up to your subject, thereby exaggerating the perspective distortion and making heads look ugly. (Heck, I got beaten over the head more than enough for that by my photography lecturer!) If you want to fill your frame, rather pick a longer focal length / smaller FOV.

* Although ortho cameras aren't used / don't exist in real life, it's still pretty useful to toggle it on and off, because it's the rough equivalent of switching to a telephoto lens and running really far away from your subject. Pretty much what traditional sculptors wish they could do. And they're useful for making accurate measurements, if you need to, especially for front/side views.

---
tldr; Even with a fixed focal length, you get varying degrees of persp distortion anyway. Traditional sculptors and portrait photographers like stepping back/using longer focal lengths/lower FOV because of lessening distortion. Maybe we should too.

pior

This is in a nutshell the one huge problem with Zbrush. The program is awesome on all accounts but perspective perception is just flawed in it (even in P mode) and the surface reading of materials is odd with either matcaps and regular materials. The forms just don't "wrap" like they should. It's quite hard to pin point but since it is all 2.5D rendering it kinda makes sense.

The only safe practice is to regularly export to an ordinary 3D package, but that really is a pain because it means working blind half of the time! I have been using DeepExploration for that lately. One can also use GoZ with Max, Maya, Sculptris, and so on. However the best solution is still to export to Mudbox, since It will let you use tools similar to Zbrush to further tweak proportions.

I too really like the look and feel of an ortho bust - it gives that nice boxy kind of visual strength. It might actually be quite fine for some uses, like a small scale toy print since we basically see those "from a distance". But for game stuff it really doesnt work. I am not sure which FOV numbers work well, but in general, the default settings of any regular 3D app are quite representative of an average game camera. Now of course the scale of the model is important too. I found the default Mudbox cube to be a really good yardstick for a human bust.

A setup I've been using :


Good luck !

cryrid

I still prefer the perspective over ortho unless it comes to perfect front/sideviews.

The FoV can always be dialed back (although it doesn't seem that far off to me), and there are other factors to take into consideration as well such as if local transforms mode is also active with perspective, or if you have it set to auto adjust to the distance in newer versions.

Neox

the biggest issue is that the fov is bound to to the scale of your object, so if you import a bust, and then import the rest of the body it gets warped all the time, it is super annoying especially on long characters, dinosaurs for example are awesome to work on with this crappy perspective, it feels totally off most of the time, with a huge ass in the background

JamesWild

I see you people are throwing around FOV angles, but it's important to note whether you're talking about the actual field of view or the theta. A lot of programs ask for a fov value but what they're really asking for is the theta.

Noth

What do you mean, you people !? Polycounters ?! Jokes. This is a great thread. Thanks, I read the whole thing. Does mudbox have a better perspective setup then?

Noth

Cyrid can you you elaborate on your local transformations comment?

Neox

Noth wrote: »

What do you mean, you people !? Polycounters ?! Jokes. This is a great thread. Thanks, I read the whole thing. Does mudbox have a better perspective setup then?

mudbox has a perspective, zbrush doesn't

BradMyers82

Gonna necro this thread as I recently googled this exact topic to see what others say.  

Here's my 2 cents:
My personal method is to first guess perspective of the concept, then work in that perspective in zbrush. If I think the concept is drawn very flat, I use less perspective and if its very distorted with fov I use more.  I usually tweak the fov several times in zbrush as I get further in the sculpt as well.  45 or 50 in zbrush is usually what I use for heads. 

So once I get the model looking very close to the concept in zbrush, with major forms, then I export to keyshot for another comparison.  This almost always leads to my model looking way off in multiple areas once in keyshot (keyshot is trustworthy with its fov distortion imo so how it looks there is all I care about).  For heads, 85 focal length in keyshot seems about right usually.  Then I'll take screen grabs from keyshot and overlay the concept in photoshop to see the differences. I then make the necessary adjustments blind in zbrush based on this back and fourth process of comparing concept to model in keyshot.  You can spend a lot of time matching stuff up in the phase, but its almost always worth the effort.  When I look at the model from before this pass it usually looks pretty shitty by comparison.

I find that larger objects matching in zbrush works better then smaller, so head studies are probably the most challenging in terms of dealing with zbrush's wonky fov.

This process yields the most accurate results for me, if anyone else has more advice on the subject I'd love to hear it!