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Piranesi's Perspective Trick (2019)
- deleted 2y ago[deleted]
- damnitbuilds 2y agoIn the image with the caption: "Normal homography perspective transformation produced in GIMP. Note how squashed the buildings at the right and left are when taken in isolation" The building at the right is not squashed ? It is wider than in the Piranesi picture above.
- achr2 2y agoThey mean distorted, not squished for both.
- SamBam 2y agoIt would have been nice to show a few more easy-to-understand comparisons. The "street view" image was nice, but blurry. Ditto with the map. I think if the last image of the two buildings had been shown side-by-side with the "correct" perspective, that might have helped explain the article.
- inanutshellus 2y agoThis was a really cool article and I hope others read it through, but yes, it took me way too far into the article to "get" what he was saying was wrong with the perspective.
- JKCalhoun 2y agoYeah, I thought better (cleaner?) examples would have helped.
- morley 2y agoI wonder how hard it is to change a game engine to render images like this, and if the effect would be preserved while panning.
- svachalek 2y agoI think the difficulty comes from it being context dependent, it's not a consistent distortion of the true image the way most projections are, it identifies synthetic structures in the foreground and warps everything else (including similar structures in the background) around them. It should be possible for an AI filter though.
- stronglikedan 2y ago> The building at the right is not squashed ? It is wider than in the Piranesi picture above. The building on the right is squashed, in isolation. When you take the building by itself (in isolation), it is indeed wider than the picture above, but it is also the same height, i.e., squashed.
- brookst 2y agoCame expecting commentary on the POV used in the (excellent) novel, learned great stuff about visual arts and incidentally more context about the book. Thanks for posting!
- achr2 2y agoThis is really interesting, I'd love to see this perspective incorporated into mapping software like google maps/streetview.
- aqfamnzc 2y agoGreat article. And thanks for the correct OSM attribution in your map images. :)
- SamBam 2y ago> By legibility I mean that the Piranesi distortion is easier to read, and that to anyone unfamiliar with photographs, that hasn’t grown up with TV, photographs and magazines, the Piranesi version would look much better, and the true perspective would look rather odd. I think this is a key point that people are often unaware of. For instance, whenever I see a modern artist who has painted photorealistic art, I read discussion about how amazing it is that this artist can paint something so perfectly life-like, and the Renaissance artists were clearly inferior, since they couldn't paint with such skill. Besides the obvious discussion about the purpose of art, the other question is whether a photorealistic painting is actually more "lifelike?" Sure, it represents the world exactly the way that a camera sees it, but does it represent the world exactly as we see it? With our human brains we are filling in details, we are focused on the subject of the painting, we are distorting, we are re-mapping shades of color to what we know they ought to be. "Lens blur" in particular isn't remotely the way our eyes perceive the world: our eyes can never roam around the unfocused parts of our own image, rather we ignore the blurry parts unless we specifically try to notice them, and anything we try to focus on becomes sharp. So I appreciate the authors recognition that Piranesi's perspective may indeed be closer to how we perceive the world than "correct" perspective.
- bonoboTP 2y ago> rather we ignore the blurry parts unless we specifically try to notice them, and anything we try to focus on becomes sharp. Unrelated to perspective: Artists often put more detail in places that you're "supposed to" look at, and leave other things more as a blurry sketch, and our eyes naturally don't linger on those parts. What's interesting to me is that I can often recognize AI art by the way it doesn't make use of this, it tends to make everything equally detailed.
- jcalx 2y agoI learned this back when I used to make maps for Source games (Team Fortress 2, CS:Source, etc.) — at first I sprinkled props and detailed geometry equally throughout the level, but it's better (in terms of art direction, player attention, and performance optimization) to put details in places that "matter". Valve does this [0] in their official maps and it's actually hard to notice until you really pay attention to it. [0] https://nodraw.net/2010/08/tf2-density-of-detailing/ https://nodraw.net/2010/08/tf2-density-of-detailing/
- thewellis2 2y agoPiranesi's imaginary prisons are worth a viewing. Great gothic prisons from a fever dream rendered in a similar fashion to these engravings.
- smokel 2y agoHere you go: https://en.wikipedia.org/wiki/Carceri_d%27invenzione https://en.wikipedia.org/wiki/Carceri_d%27invenzione
- bemmu 2y agoI'll take this opportunity to drop the fact that I'm kind of obsessed with the book "Piranesi", where the main character (named after the artist in the article) survives in a world which is just endless corridors of classical architecture, statues, and staircases. It's an incredibly calming experience, I've listened to the audiobook over 10 times before sleep. Highly recommended.
- AndrewStephens 2y agoI second this review - Piranesi is a fantastic and inventive novel.
- jackstraw14 2y agoRead the book once, will definitely check out the audiobook. I got in the habit of reading it before bed too, sounds perfect.
- asicsp 2y agoA very different book, but I loved reading "Jonathan Strange & Mr Norrell" [0] as well by the same author. [0] which used footnotes to great effect
- colkassad 2y agoThis also has a great audiobook version. Simon Prebble really brings the characters to life.
- AndrewStephens 2y agoI enjoyed the TV adaptation as well.
- maw 2y agoIndeed. It made long walks with my dog seem all too short.
- WD-42 2y agoClicked the article for the book, stayed for the awesome explanation on how perspective works.
- bonoboTP 2y agoIf liked this, you might also like: https://aaronhertzmann.com/2024/06/10/perspective-distortions.html https://aaronhertzmann.com/2024/06/10/perspective-distortion... https://aaronhertzmann.com/2024/09/09/dvc-multiperspective.html https://aaronhertzmann.com/2024/09/09/dvc-multiperspective.h...
- 01HNNWZ0MV43FF 2y ago> it isn’t possible to construct a camera or a computer program to render a view that does this Hmmm > The mathematics of this is quite simple If so then surely a program could be written
- 01HNNWZ0MV43FF 2y agoSomething is up with that green building on the right, too. It's wider in the "true perspective" views, wider even than the ortho view
- jihadjihad 2y agoIt confused me too, and maybe I am wrong, but I took it to mean, "can't render an existing (i.e. non-Piranesi) view into Piranesi perspective." Meaning, if you're an artist starting from scratch, you could do it (using the math given)--and some of those examples seem like aspects of one drawing employ Piranesi perspective while others don't. So maybe the author was just saying if the work was drawn with "true" perspective throughout, there isn't a programmatic way of converting the entire thing over to Piranesi. That's at least how I read it, I'm curious about it too!
- JKCalhoun 2y agoYes, perhaps the computer needs information on which pixels belong to which buildings in order to apply perspective-per-object, rather than perspective-to-the-entire-image?
- hulium 2y agoHe has written a program: https://github.com/brunopostle/piranesi https://github.com/brunopostle/piranesi The problem is that it is a method for projecting a rectangle, not a full 3D scene. I can imagine though that it could be extended to a full projection if you specify a central axis along which the perspective trick happens.
- jmilloy 2y agoDoing it with a camera/computer requires identifying the objects that need to be drawn in "Piranesi Perspective". The mathematics of laying out the objects is quite simple, but rendering a raster image into a view such that the key objects have this perspective probably isn't possible. You would need to vectorize the image in a general way. I don't know the state of the art in that field, but it sure seems hard.
- tobr 2y agoSurely this introduces some curvature to the diagonals? I can't see how the perpendicular lines can be in correct perspective with the diagonals being parallel unless something is curving. I guess because it's preserving the perpendicular lines and the curvature is subtle, it's not very noticeable in typical architectural pictures.
- amelius 2y agoI really hate it when a designer takes a perspective rendering with the camera really close, and then modifies the object so that it looks that way from a normal distance. Not sure if that's what happened here (can't read the article), but designers should not do that.
- ibaikov 2y agoWow, this is SO cool! It looks better because you can see the details of objects far from the 'camera'. This is basically what you do when you are there in reality, constantly refocusing on objects. This perspective trick to me is a map of zones on the picture on which I will focus. I wonder what would happen if we'd render videos using it, and maybe games? Could this be a solution to better graphics? Would movement ruin it? Please tell me!
- rossdavidh 2y ago"So here is a general 2D remapping as a prototype replacement for the perspective tool in image editors (I have no ability to add this to GIMP, somebody else needs to step up)..." Well given that this is HN, if there's any forum where somebody has experience contributing to GIMP, it should be here. Any takers?
- ChrisMarshallNY 2y agoThat's a really cool article! TIL. It makes absolute sense, but I never even thought about doing it that way. I was trained as an artist, and I always did perspective the "classic" way. It's entirely possible that this might not work on some subject matter, but it works great on buildings.
- jcalx 2y agoPanini projection is built into Unity and Unreal. From the documentation from the latter [0] you can see how it's essentially a cropped fisheye-ish projection. That doc also has (in my opinion) a clearer comparison on how the two projections differ, especially looking at the layout of the square tiles on the floor in the first set of pictures. [0] https://dev.epicgames.com/documentation/en-us/unreal-engine/panini-projection-in-unreal-engine https://dev.epicgames.com/documentation/en-us/unreal-engine/...
- dust42 2y agoThe panotools wiki has a good comparison of different projections of the same photo. Google Streetview uses equirectangular pictures to store 360° images. Panini is another type of equirectangular. Examples Panini: https://wiki.panotools.org/File:Ben_Equirectangular_panini.jpg https://wiki.panotools.org/File:Ben_Equirectangular_panini.j... Equirectangular: https://wiki.panotools.org/File:Big_ben_equirectangular.jpg https://wiki.panotools.org/File:Big_ben_equirectangular.jpg Full list: https://wiki.panotools.org/Projections https://wiki.panotools.org/Projections
- RheingoldRiver 2y agoif you have any connection to the admins of that wiki, it would be great to get MultimediaViewer extension enabled - https://www.mediawiki.org/wiki/Extension:MultimediaViewer https://www.mediawiki.org/wiki/Extension:MultimediaViewer they're on 1.35 right now which is a bit out of date (lifecycle - https://www.mediawiki.org/wiki/Version_lifecycle https://www.mediawiki.org/wiki/Version_lifecycle) but an older branch of MMV should work fine on 1.35
- account42 2y agoI hate this behavior on Wikipedia. Worst part is that people then share links to those views which don't work without running javashit.
- RheingoldRiver 2y agoIf you have an account, you can disable it in preferences. Appearance -> Files -> "Enable Media Viewer" Toggle that off and it'll never happen again
- account42 2y agoBlocking the scripts in question works better for that without the need to make an account. But neither solves the problem of others sharing links to image views that won't work without scripts enabled.
- deleted 2y ago[deleted]
- _wire_ 2y agoLast Year at Marienbad (1961) https://en.m.wikipedia.org/wiki/Last_Year_at_Marienbad https://en.m.wikipedia.org/wiki/Last_Year_at_Marienbad
- rozab 2y agoHere is the Panini projection paper, it's a good read[0]. Unreal Engine has support for it as a post-processing filter[1], but I don't know of any games using it. [0]: http://tksharpless.net/vedutismo/Pannini/panini.pdf http://tksharpless.net/vedutismo/Pannini/panini.pdf [1]: https://dev.epicgames.com/documentation/en-us/unreal-engine/panini-projection?application_version=4.27 https://dev.epicgames.com/documentation/en-us/unreal-engine/...
- aappleby 2y agoLol, it's literally affine texture mapping.
- Etherlord87 2y agoRead the article and look at the examples - there still is perspective, just no perspective distortion (or the other way around, there is a perspective distortion to keep some lines parallel, where in normal view this wouldn't be the case).
- nyanpasu64 2y agoMy theory is that most perceived perspective errors arise when a photograph captured with a wide field of view is shown in a narrower one; a perspective-"distorted" image looks more realistic if you put your nose up to the screen so the photograph fills more of your field of view (enlarging the center and eventually squashing the edges). And tricks like Panini projection and Piranesi's arches are ways of making features at the edge of the screen "take up" the correct amount of viewing angle (without bending straight lines) when the painting takes up less of your vision than the original scene.
- frankfrank13 2y agoA great example of something you can feel but I never had the words for. > But here is the same elevation drawn using correct rectilinear perspective. I hope you will agree that the Piranesi version is much more legible, the furthest house above is easier to see and the nearest house isn’t horribly distorted as it is below. The section with this bit has some pictures that really illustrate the effect.I wish there was an easy photoshop way to recreate this
- Fraterkes 2y agoI half remember an articled or docu from a while ago where someone was analyzing the perspective in some studio Ghibli backgrounds, finding that many are artistically "distorted". When this was brought up to one of the artists, they responded along the lines of: "The western idea of 1, 2 and 3 point perspective is just one way of drawing perspective and not necessarily more 'correct'." (I guess that's true, even if you think of 1 and 2 point perspective as cropped versions of a 'true' perspective image, the lines wouldn't be completely straight in reality. It's all different kinds of artistic license).
- senkora 2y agoI think that this trick or something like it is used in ski mountain maps. For example: https://files.skimap.org/js03b74i9eokcg2y1iakwdtv2av6.pdf https://files.skimap.org/js03b74i9eokcg2y1iakwdtv2av6.pdf I don't know how to confirm this; the distortion just feels similar to me.
- novosel 2y agoI highly recommend to the people cross-interested in film theory, the Eisensteins book essay The philosophy of composition. At great length talking about Piranesi perspective.
- kazinator 2y agoThis reminds me of an issue in vintage computer graphics. Say you have a game with some polygons happening, and they're nicely rendered in 3D perspective. You'd like to add some snazzy textures to them. Here's a problem. The textures have to be put through a perspective projection. As in every pixel. It's possible to cheat. You can simply use a bicubic stretch or even linear. It really shows up when the polygons are large and they rotate to create deep perspective. You see an artifact whereby the center of the texture does not stay centered on the polygon as it rotates.
- animatethrow 2y agoPlaystation 1 didn't do perspective correct texture mapping. If you scroll way down this WebGL tutorial page a few examples are shown: https://webglfundamentals.org/webgl/lessons/webgl-3d-perspective-correct-texturemapping.html https://webglfundamentals.org/webgl/lessons/webgl-3d-perspec...
- bazoom42 2y agoPiranesi also made an amazing set of depictions of imaginary “dungeons”, sometimes using escher-like trick perspective.