schmoron13 Posted March 6, 2003 Share Posted March 6, 2003 I've noticed people referring to this term, but have no clue as to what it is....any definitions? Thanks Link to comment Share on other sites More sharing options...
kid Posted March 6, 2003 Share Posted March 6, 2003 perspective in the vertical axis. Link to comment Share on other sites More sharing options...
schmoron13 Posted March 6, 2003 Author Share Posted March 6, 2003 still don't get it....do you mean that parallax implies that there is perspective in the vert axis, and if so, is that really a negative thing? Link to comment Share on other sites More sharing options...
CHE Posted March 6, 2003 Share Posted March 6, 2003 Parallax: The apparent angular displacement of an object with respect to a point of reference or coordinate system. Parallax is caused by a difference in altitude or point of observation. I know that Nisus will come up with a better definition. right? :ebiggrin: Link to comment Share on other sites More sharing options...
AHaidar Posted March 6, 2003 Share Posted March 6, 2003 For a quick demonstration look at an object a foot or two in front of you. Cover one eye. Then, while uncovering that eye, cover the other one. Do this a few times. The apparent shift in the object's position is parallax. Your eyes are viewing the same scene from slightly different positions. A camera that doesn't have a TTL (through the lens) viewfinder can also be used as an example. Close up photos will appear cropped when compared to the viewfinder image. To compensate for the difference between the lens and viewfinder there will be a couple of hash marks in the viewfinder that indicate the "cropping" of the recorded image due to parallax. For my old Nikon 990 they are on the left since the lens is to the right of the viewfinder. Link to comment Share on other sites More sharing options...
nisus Posted March 7, 2003 Share Posted March 7, 2003 lol che! I'm not so interested in a definition, rather in how to avoid it nisus Link to comment Share on other sites More sharing options...
Gnarly Cranium Posted March 7, 2003 Share Posted March 7, 2003 OOooooooh, so this is related to the Mystery of the Moving Pillow!! And the way chain-link fences go wheeeeeoooowwweeeeee when you get a certain distance from them! Link to comment Share on other sites More sharing options...
Iain Denby Posted March 7, 2003 Share Posted March 7, 2003 Yeah, parralax is nothing to do with converging virticals. Link to comment Share on other sites More sharing options...
nisus Posted March 7, 2003 Share Posted March 7, 2003 ah... it's all in the head... Link to comment Share on other sites More sharing options...
John Dollus Posted March 7, 2003 Share Posted March 7, 2003 >>lol che! I'm not so interested in a definition, rather in how to avoid it One word: Photoshop I think Viz4 and Max5 w/design extensions added a new camera type to correct this as well, but not sure as I have not upgraded. Link to comment Share on other sites More sharing options...
nisus Posted March 7, 2003 Share Posted March 7, 2003 you don't need those modifiers/skew... just a plain understanding that target and camera should be at the same height... ow... and crop after rendering! Never put a horizon at half the height... the rule of thirds! rgds nisus Link to comment Share on other sites More sharing options...
bigcahunak Posted March 7, 2003 Share Posted March 7, 2003 Dear Nisus, I know you live by your rules, and you know not each and every one of us lives by your, and that 100% OK. To each his own. But, I wonder what would you do when you have a building like the one kid posted, and you want to show it all, while still being able to see some details (say being close to entrance. I can understand placing the camers at eye level (thats a rule of mine as well) but I do like to raise my head up and look at the sky from time to time. And in real life strait lines do get that deflection only that we dont grasp it as suce (a deflection). Regards. Link to comment Share on other sites More sharing options...
STRAT Posted March 8, 2003 Share Posted March 8, 2003 i'm with the guy on the scrambling bike - i too like to look way up into the sky sometimes converging verticles has always been a problem for us. We can quite easily get away with it to a certain degree because it is quite normal, but how to minimise it - Just keeping the camera and target at the same level then cropping the image later is a pretty daft solution, even tho it does work in certain circumstances - biggest problem being is with things like sky scrapers - standing at ground level, whilst keeping the target point at ground level chops off 4/5's of my building! Another solution is to change camera lense size. ie, instead of use say a 35mm or 50mm lense use a 200mm or 300mm or higher lense, and just stand further back. not always easy to stand way back in a tight model but easier and faster than rendering a huge render all at eye level where you'll be cropping off allot of it anyway. what other solutions have ppl got? The scale and usability of models must be considered. rendering at a far distance isn't the ideal, neither is huge rendering for post cropping. post photoshopping also ISN'T a solution btw and it distorts the image unnaturally and too noticably. is there any camera altering scripts or modifies available? [ March 08, 2003, 02:10 AM: Message edited by: STRAT ] Link to comment Share on other sites More sharing options...
kid Posted March 8, 2003 Share Posted March 8, 2003 so 3-point perspective, vertical convergance, or whatever, isn't parallax then? Oops :angeuhoh: Link to comment Share on other sites More sharing options...
nisus Posted March 8, 2003 Share Posted March 8, 2003 Hi all, I try to avoid parallax whenever I can, but in a few cases one has to live with it. Very tall buildings generate these exceptions, and the only way is to use a tele(zoom)lens, like strat described. Hence the undesireable distortion, there are a few tricks one can apply. So when parallax cannot be avoided, I personally augment the effect even more! I do so by rolling the camera so that the dominant verticals get closer to diagonals or make sure one edge is aligned to the horizontal or vertical frame, while all other lines converge to a corner. The training one can get to understand and devellop a good feeling for this, is to walk around with a digital camera and watch the screen only. Turn the camera up and down, and try to make good framings of the surroundings. Look for dominant lines, next faces and planes. Careful that you don't get overrun by a bus! (Btw, after I finish my current book and two others, I've planned to read a book on architectural photography, so I'll keep you informed upon new tricks...) rgds nisus Link to comment Share on other sites More sharing options...
mzagorski Posted March 8, 2003 Share Posted March 8, 2003 So... *this* image *is* parralax? And what you are trying to avoid... is people standing say.. 2 metres (6') away from a building with some ridiculous camera lens that shows their complete building... that wouldnt be possible with human eyeballs Damn.. I think I saw a good example of what we are trying to avoid... some render by a first year student from my architecture school... must make a quick example in Max. Link to comment Share on other sites More sharing options...
nisus Posted March 8, 2003 Share Posted March 8, 2003 even some architects got very famous by exagerating and over-using parallax... right Zaha? Personally I like OR no parallax OR very strong parallax because that way the artist clearly decides the shot and takes his position... All the rest is rather vague, troubled, guesswork... rgds nisus Link to comment Share on other sites More sharing options...
AHaidar Posted March 8, 2003 Share Posted March 8, 2003 I'm going to have to disagree with nisus and say that Zaha Hadid's renderings aren't examples of parallax. They are examples of exaggerated foreshortening and 3-point perspecitve. Whether or not they are used excessively is up to the viewer. Link to comment Share on other sites More sharing options...
nisus Posted March 9, 2003 Share Posted March 9, 2003 In that case I think you'll have to come up with a definition that clearly marks the difference between 'exaggerated foreshortening and 3-point perspecitve' and 'parallax'... ;-p rgds nisus Link to comment Share on other sites More sharing options...
AHaidar Posted March 9, 2003 Share Posted March 9, 2003 Warning, pedantic and potentially coma inducing post follows. Read at your own risk. There isn't a problem with the definition of the word; however, there is a usage problem. People call the effect in mzagorski's screen cap parallax even though it isn't. As CHE pointed out: The apparent angular displacement of an object with respect to a point of reference or coordinate system. Parallax is caused by a difference in altitude or point of observation. Or as it pertains to human vision: The apparent displacement in position undergone by an object when viewed by either eye singly. Either way the definition requires two images with the same focus point taken from two different positions. Unfortunately foreshortening and 3-point perspective are somewhat awkward and don't sound as cool as parallax. Maybe we need to create a new word that is specific to architectural images. zahallax: the combination of foreshortening and 3-point perspective to distort objects in an image. Zahallax is best used to excess. Restrained or accidental implementation frequently leads to aggravation usually after the utterance of "Something doesn't look right." by a client or project manager. Zahallax is often mistakenly called parallax (I had to throw that in). I'm open to other suggestions. Maybe zeallax (zee-ah-lax) or distallax. /left brain word fetishist Link to comment Share on other sites More sharing options...
Ernest Burden III Posted March 9, 2003 Share Posted March 9, 2003 Unfortunately foreshortening and 3-point perspective are somewhat awkward and don't sound as cool as parallax. Maybe we need to create a new word that is specific to architectural images.Well, it is not something commonly seen in traditional media rendering, or in those done with architecturally-oriented CG renderers. Therefore, the most logical word would be: MAXallax Thank you very much, Link to comment Share on other sites More sharing options...
CHE Posted March 9, 2003 Share Posted March 9, 2003 LOOOOOOOL That was a good one Ernest! MAXallax LOOOOOOOL Well, it is not something commonly seen in traditional media rendering, or in those done with architecturally-oriented CG renderers. I totally agree with you. Link to comment Share on other sites More sharing options...
nisus Posted March 10, 2003 Share Posted March 10, 2003 as 'max' is not the only program used for 3d, and CAD was the start of all this nonsense, I suggest to change maxallax into 'cadallax'... ;-p rgds nisus Link to comment Share on other sites More sharing options...
STRAT Posted March 10, 2003 Share Posted March 10, 2003 ahh, like those - Link to comment Share on other sites More sharing options...
Ernest Burden III Posted March 10, 2003 Share Posted March 10, 2003 No way, My favorite CAD program has been able to do panned two-point perspectives since before Autocad even had a perspective command ( which they called DVIEW just to make it easy to understand)--ACAD still cannot easily pan a perspective view, if at all. And my favorite rendering app--Lightscape--has ALSO always been able to do it. But MAX can't, at least without writing a view modifier (see earlier thread on this subject). So it isn't ALL CAD and rendering apps, it just those by Autodesk that cannot do a proper architectural view. as 'max' is not the only program used for 3d, and CAD was the start of all this nonsense, I suggest to change maxallax into 'cadallax'...Nice cars! Link to comment Share on other sites More sharing options...
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