[HN Gopher] Curvature consistency in Apple hardware and software...
       ___________________________________________________________________
        
       Curvature consistency in Apple hardware and software products
       (2017)
        
       Author : adas4044
       Score  : 148 points
       Date   : 2022-12-24 08:22 UTC (14 hours ago)
        
 (HTM) web link (hackernoon.com)
 (TXT) w3m dump (hackernoon.com)
        
       | ginko wrote:
       | The squircle was actually Nokia's design language they used for
       | Meego[1]. Back then Apple just used basic squares with rounded
       | edges, the "unique" curverture mentioned here happened later.
       | 
       | [1] https://interuserface.net/2011/06/own-a-shape/
        
       | ajuc wrote:
       | If I have to choose this or good thermals...
        
       | aflam wrote:
       | Last year I wanted to have a table custom built using those
       | shapes. It's easy with CNC:
       | https://shapescience.xyz/blog/creating-a-super-ellipsis-tabl...
        
         | CSSer wrote:
         | Very cool article! Thanks for sharing. Is numpy just global in
         | Python now? I see it everywhere, and I eventually sound it out.
         | Yet I never fail to have a few moments where I go, "Wait, what
         | is 'np'? Oh, yeah... Numpy." And I always feel like just
         | listing it as an import in the snippet would've solved it.
        
           | tonyarkles wrote:
           | Just a "standard" convention. I've been doing a bunch of
           | analysis work lately and almost all of the scripts start with
           | something like:                   import numpy as np
           | import pandas as pd         import seaborn as sns
           | import sympy as sp
        
         | dagmx wrote:
         | > It's unlikely you can do it at home...
         | 
         | I think you could if you had a small bench top cnc or laser
         | cutter.
         | 
         | You'd have to split up the DXF into pieces that fit on your
         | bed, but you'd be able to make a template by joining the parts
         | together.
         | 
         | Then rough cut your workpiece to the template, followed by a
         | flush bit router.
        
       | muro wrote:
       | I wish they would put in at least some basic effort into
       | smoothing that sharp edge where wrists often rest when using the
       | MacBook, rather than just the curvature of the corner. Any cheap
       | laptop is nicer to my wrists than a MacBook.
        
         | eternityforest wrote:
         | Apple has beautiful squircle curves the rest of us can't have
         | unless we want expensive CAD tools and extra JS files, but they
         | also have plenty of sharp transitions. Look at their cables,
         | that have no strain relief, being a bad influence on every
         | other cable for a decade.
         | 
         | It's basically just Bauhaus design but with a few nice soft
         | features, it's gonna be a bit uncomfortable, it's gonna be
         | expensive, it might compromise functionality, all to create a
         | sense of precision, authenticity, and high-endness.
        
           | crazygringo wrote:
           | What are you talking about, every Apple USB and Lightning
           | cable I've ever had has had strain relief on both ends.
           | 
           | There's the main plug in a plastic housing, and then there's
           | an extra-thick rubber part about a centimeter long which is
           | the strain relief wrapped around the cable, and then the rest
           | of the cable itself. Clearly visible in any product
           | photograph close-up.
        
             | Waterluvian wrote:
             | My apple cables are consistently the first to wear out. I
             | must be using them wrong.
        
               | dividedbyzero wrote:
               | It's always weird to read things like that because I
               | definitely mistreat my cables, and I've had lots die, but
               | my Apple ones hold up very well. I have just one
               | Lighthing cable that recently broke and that one was from
               | 2013 IIRC so I guess that's ok. Everything else seems to
               | hold up about as well as expensive Anker cables, if not
               | better, including Macbook chargers going back to 2005 or
               | so. I'm in the EU though, maybe the cables I get are
               | different in some way?
        
               | rumori wrote:
               | All my Apple cables have fallen apart, granted it took
               | them 3-5 years, but still. Never had so many issues with
               | any other brand. And it's something I see with everybody
               | I know. I'm in central Europe.
        
               | ip26 wrote:
               | Different folks mistreat in different ways. I'm struck by
               | the number of people who will _yank_ their laptop to move
               | the power brick, for example, which is of course the
               | worst case scenario for cable strain relief and leads to
               | premature socket failure in the laptop.
        
               | jsjohnst wrote:
               | > It's always weird to read things like that because I
               | definitely mistreat my cables, and I've had lots die, but
               | my Apple ones hold up very well.
               | 
               | Just wanted to say, you aren't alone. I don't do anything
               | special with mine, I'm sure I mistreat them as much as
               | the next person, but like never have the kind of damage
               | I've seen others have or complain about.
        
               | gruez wrote:
               | On the other hand all my cables are just fine, apple
               | cables included. It's probably not due to lack of use; I
               | use them nearly every day for years now.
        
             | eternityforest wrote:
             | Ok, maybe I should have said very minimal and near
             | ineffective strain relief. A cheap braided USB-C generally
             | has 2 or 3 times the length and thickness.
        
             | seltzered_ wrote:
             | Every Apple Lightning cable I own has a tear around the
             | cable housing just outside of the strain relief.
             | 
             | There's guides on how to workaround it using things like
             | Sugru or tape, but still frustrating.
        
             | pja wrote:
             | Yes & it doesn't work very well. Or at least it didn't,
             | 
             | Apple has been notorious for sacrificing good strain relief
             | on their cables in pursuit of aesthetics for years.
             | Possibly things have improved now that Ive has left, but
             | there was a period a few years ago when everyone I knew
             | with a Macbook had wrapped the power cable in electrical
             | tape because the cable housing had failed just above the
             | (useless) strain relief sleeve you describe.
        
               | dutchCourage wrote:
               | I had the same with my previous MBP, I had the machine
               | for ten years and had to purchase two new power bricks
               | along the way. Thankfully the new cables are nicely
               | braided and replaceable without buying an entire new
               | brick.
        
               | Gigachad wrote:
               | I think it was less the strain relief and more the rubber
               | they used. It would go gummy and fall apart after a few
               | years. I absolutely remember around 2013 everyones
               | MacBook charger would fail like this.
               | 
               | But they have changed the design a lot since then so I no
               | longer think this is an issue. The brick is now usb c so
               | you can swap the cable without needing an expensive
               | brick, and the MagSafe cables they now include are
               | braided instead of rubber.
        
               | newaccount74 wrote:
               | The USB-C charging cable from the 2020 M1 Macbook still
               | has the issue of straining just after the strain relief.
               | It's not a good cable. The only good thing about it is
               | that is a standard cable and you can replace it with a
               | more reliable one.
               | 
               | Whether the cables with the braided sleeve are better is
               | something that remains to be seen.
        
         | muro wrote:
         | Also: if they could create a gap between the screen and the
         | keys, so the screen is not always smudged after closing the
         | MacBook. Aka, if you use your MacBook as a laptop, the screen
         | will be dirty even if you are careful to never mistakenly touch
         | it.
        
           | tinus_hn wrote:
           | Do the keys also scratch the screen like on a Dell or HP?
        
           | kitsunesoba wrote:
           | I haven't had a much trouble with this on my MacBooks, but
           | based on observation (relatively small sample size, so take
           | with grain of salt) this is exacerbated by tightly packing
           | them in e.g. a bag with books/tablets/etc or stacking things
           | on them. As long as I've avoided those situations I don't get
           | key tracks.
        
           | StringyBob wrote:
           | For at least one gen of MacBooks (maybe the ill-fated 2016
           | MacBook Pros?), this was actually a design fault. In the
           | battle for thinness there was not enough separation between
           | screen and keys when closed, leading to damage to screen
           | coating over time. Newer versions had a slightly larger
           | rubber lip on the screen to increase the separation - as I
           | noticed after getting a replacement for a damaged model
        
             | muro wrote:
             | I now have the M1 MacBook Pro and it still has that issue.
        
               | CSSer wrote:
               | On the brightside, if you ignore it until you can't see
               | your screen properly it's like the heavens have opened
               | once you finish cleaning it.
        
               | tosc wrote:
               | Have you tried putting gravel in your socks at the
               | beginning of the day? It feels great when you get home
               | and finally take them off.
        
               | CSSer wrote:
               | You win. I chuckled. You know I was making a bit of a
               | joke too, right?
        
               | solarkraft wrote:
               | I had an M1 pro and have an M1 air, both with screen
               | protectors (that are matte but quick to show smudges) and
               | haven't noticed this.
        
             | GrayShade wrote:
             | This can happen on other laptops, especially to cat owners.
        
           | djaychela wrote:
           | I always put something between the screen and the keys when I
           | close it - not only finger grease, but eventually you get
           | damage on the screen from grit on the keys or the hard edge
           | by the track pad. A sheet of A4 paper was the thing for a
           | while, but then I got some of the material you get in new
           | laptops and use that now (it's made from recycled PET, and
           | black).
           | 
           | Bad design, imo.
        
         | joezydeco wrote:
         | But then you would have a rounded surface matched up with a
         | sharp one (the top of the display) when you close the lid and
         | that wouldn't look sexy at all. Two rounded edges would be even
         | worse.
        
           | nomel wrote:
           | The marks in my wrists look worse, to me.
        
       | baybal2 wrote:
       | [dead]
        
       | c-smile wrote:
       | Isn't that because those corners are rendered as Bezier curves
       | that are H/W accelerated?
       | 
       | Usually, small radii are emulated by beziers:
       | https://spencermortensen.com/articles/bezier-circle/
        
       | ryandrake wrote:
       | I guess I have really bad eyes but I can't tell the difference at
       | all. They both look like rounded corners to me. I don't think the
       | aesthetic effect is that pronounced. I'd like to see the author
       | do a blind taste test and be able to identify this magical
       | "curvature comb" without seeing the brands.
        
         | noodlesUK wrote:
         | I think it's definitely something that's visible in 3d on a
         | somewhat reflective surface, but it's definitely harder to tell
         | projected top down in 2d for me.
         | 
         | edit: it's definitely subtly noticeable in the image posted by
         | sibling
        
         | CharlesW wrote:
         | Out of curiosity, are you really not able to tell which is
         | which in this unlabeled image? https://imgur.com/a/xhCZgds
        
           | noodlesUK wrote:
           | (Not parent) Seeing this, it's definitely noticeable but it's
           | very subtle.
        
           | ryandrake wrote:
           | On those I can see that one has a larger corner radius than
           | the other but that's it.
        
       | nickpinkston wrote:
       | The fun hardware aspects of this are how they choose to form
       | curves for the aluminum MacBooks using cold forging to get create
       | the broad curves of the device and then post-machining the
       | keyboard, chamfered (angled) edges, and form tapping the screw
       | boss threads - ie pressing not cutting the threads into the
       | material.
       | 
       | Variable radii curves take forever to machine and must be
       | polished, so that's only done on the cold forging die (and takes
       | forever to do), so the die can then impart the geometry on the
       | aluminum blank in only seconds in the forging press.
       | 
       | This is also how high-end aluminum car wheels are made with all
       | their complex curvature.
       | 
       | Funny enough, they don't cover the forging in this video that
       | describes most of the rest of the process, so I think Apple
       | must've not wanted to talk about it, as least back then.
       | 
       | https://www.youtube.com/watch?v=sxbiIpXZfG8
        
       | atoav wrote:
       | The curvature is not unique to apple though. This is widely used
       | in car manufacturing for example. Turns out not having a hard
       | transition between no curvature (straight surface) and some kind
       | of radius (so a curvature of 1/r) looks like shit on very
       | reflective surfaces, because a perfect flat mirror suddenly
       | transitions into a stretched or squashed one.
       | 
       | So you can go and make those transitions flawless by making sure
       | the curvature combs transition into each other as well (basically
       | a set of spaced out lines which you draw perpendicular to the
       | line in question where the magnitude equals the curvature). If
       | the curvature combs meet at the transition, the transition looks
       | okay. If the curvature combs are tangential to each other it
       | looks better. You can also add a second order curvature comb to
       | the first one and make sure these connect as well etc.
        
         | fmajid wrote:
         | Pierre Bezier, he of the eponymous curves, worked for French
         | car maker Renault for decades.
        
         | CharlesW wrote:
         | For anyone interested, a history of the "squircle":
         | https://www.johndcook.com/blog/2019/04/02/history-of-the-ter...
        
         | Terretta wrote:
         | > _So you can go and make those transitions flawless by making
         | sure the curvature combs transition into each other as well
         | (basically a set of spaced out lines which you draw
         | perpendicular to the line in question where the magnitude
         | equals the curvature)._
         | 
         | Would this be like the illustrations in the article labled
         | "curvature comb showing tangency" and "cuvature comb showing
         | curvature continuity"?
        
         | dang wrote:
         | Ok, we've taken uniqueness out of the title above.
         | 
         | (Submitted title was "Apple's Unique Device Curvature". I
         | assume that rewrite was intended to replace the linkbaitiness
         | of the article title, which is in keeping with the site
         | guidelines: https://news.ycombinator.com/newsguidelines.html)
        
       | bmitc wrote:
       | And yet the front part of MacBooks, where you lift the lid, is so
       | sharp and pointy it can scratch you.
        
       | virtualritz wrote:
       | This is standard knowledge in product design.
       | 
       | Most people doing font design also have a keen understanding of
       | this.
       | 
       | Even if often more intuitively that through maths.
       | 
       | That said, in 2D you can get away with tangent continuity (C1)
       | and stuff looks good.
       | 
       | I.e. while people may be able to tell the difference between a
       | square with corners that have been rounded using quadratic arcs
       | and one that uses cubic arcs or is a superellipse of some sort,
       | these are all still looking fine.
       | 
       | In 3D, outlines will also look ok but a soon as you have shading
       | anything that is not curvature continuous (C2) will stick out
       | sorely.
       | 
       | The term most often used for the visual artifact that ensures is
       | 'broken highlights' (see the photos in the article).
       | 
       | For example, if you write displacement or bump shaders and you
       | transition between ('smooth') functions and want to maintain a
       | smooth surface appearance, smoothstep()[0] is not enough. It is
       | only C1 continuous.
       | 
       | You need a higher order variant, e.g. Ken Perlin's own improved
       | version that is C2 continuous[1].
       | 
       | CAD software usually has zebra strip analysis shading which makes
       | these things stick out so they can be fixed by
       | rebuilding/retopologizing surfaces.
       | 
       | [0] https://en.m.wikipedia.org/wiki/Smoothstep
       | 
       | [1] https://en.m.wikipedia.org/wiki/Smoothstep#Variants
        
         | yummypaint wrote:
         | All major roads do this too. If the transition from a straight
         | line to moving on a circular path happened instantly, then
         | drivers would have to instantly turn their steering wheels to
         | the correct angle for the turn. Very very occasionally i'll
         | encounter a turn with that discontinuity and it feels really
         | unsafe and jarring. I wouldn't be surprised if some residential
         | roads were intentionally designed this way to help limit speed.
        
       | scotty79 wrote:
       | More on smoothness of the curves
       | https://www.youtube.com/watch?v=jvPPXbo87ds
       | 
       | As seen on HN this month.
        
         | AceJohnny2 wrote:
         | Another upvote for Freya Holmer's _amazing_ video  "The
         | Continuity of Splines".
         | 
         | She covers the insightful "reflection test" around the 28:05
         | mark: https://youtu.be/jvPPXbo87ds?t=1685 and actual "curvature
         | combs" at 32:26.
         | 
         | Finally, she covers the continuity of curvature combs that
         | B-Splines exhibit around the 54:00 mark:
         | https://youtu.be/jvPPXbo87ds?t=3240
        
       | dang wrote:
       | Related:
       | 
       |  _Apple's Icons Have That Shape for a Very Good Reason_ -
       | https://news.ycombinator.com/item?id=16294455 - Feb 2018 (5
       | comments)
       | 
       |  _Apple's Icons Have That Shape for a Very Good Reason_ -
       | https://news.ycombinator.com/item?id=13484728 - Jan 2017 (5
       | comments)
        
       | SSchick wrote:
       | Very relevant https://www.youtube.com/watch?v=jvPPXbo87ds
       | Probably use BSplines
        
         | tedd4u wrote:
         | AFAIK Alias (which the article say is in use at Apple) uses
         | non-rational uniform B-splines (or NURBS). Covered at 1:02:35
         | in the awesome video you linked.
        
       | progbits wrote:
       | In-depth explanation of curve continuity without the fanboying:
       | https://youtu.be/jvPPXbo87ds
        
       | superzamp wrote:
       | I can finally put some words on this. Tangentially (no pun
       | intended) in CSS, the poor rendering you get out of an
       | ambitiously border-radius'ed button has been driving me mad for
       | years; time to get down the rabbit hole to see how to replicate
       | that look on the web.
        
         | somat wrote:
         | So web 2.0 was basically css border-radius right, so what we
         | need for web 3.0 to emerge is border-bezier
        
         | CharlesW wrote:
         | This looks like a good place to start...
         | 
         | App: https://squircley.app/ Code:
         | https://dev.to/georgedoescode/codepen-soften-up-your-designs...
        
         | metadat wrote:
         | I had the exact same thought: How to do this in CSS?
         | 
         | Please follow-up on this thread with any discoveries or
         | learnings, would be interesting and cool to learn how to
         | replicate the nice soft curve for web assets. Depending on how
         | many different semi-reasonable approaches exist, this subject
         | and analysis would also make for a compelling and blog article.
         | 
         | Edit: Thank you Charles - wow you're so quick to have unearthed
         | and replied with squircle resources in the time it took for me
         | to compose the three sentences above.
         | 
         | p.s. CharlesW: thanks for your helpful and informative comments
         | in general, I consistently look forward to reading your
         | comments whenever I see one. Cheers and happy holidays!
        
           | CharlesW wrote:
           | I really appreciate the kind words. Happy holidays to you and
           | yours!
        
           | kitsunesoba wrote:
           | It's not CSS, but for cases where it makes sense to export
           | assets (e.g. SVGs or PNGs) Sketch has squircles as an option
           | for corner curvature on roundrects, calling it "smooth
           | corners" (v.s. "round corners"). As far as I can see Figma
           | does not offer this, but I am not well versed in Figma so the
           | option may just be hiding in some obscure panel.
        
         | davidbarker wrote:
         | This blog post is from 5 years ago, but it explains how you can
         | use CSS Houdini to make smooth corners. It's quite a lot of
         | work, though.
         | 
         | https://iamvdo.me/en/blog/smooth-corners-with-css-houdini
         | 
         | I would love it to be built into browsers as standard.
        
       | nequo wrote:
       | The curvature combs are confusing to me.
       | 
       | Is this equivalent to saying that Apple's rounded corners have a
       | continuous second derivative while naive rounded corners only
       | have a continuous first derivative but a discontinuous second
       | derivative? Or am I misunderstanding this?
        
         | amelius wrote:
         | Isn't this sort of thing common in the automotive industry?
        
           | [deleted]
        
           | toiletfuneral wrote:
           | [dead]
        
           | nine_k wrote:
           | It's very common on railways.
           | 
           | You don't want a train to suddenly experience a sideways
           | force as it enters a curve. So the 2nd derivative of the
           | position, acceleration, should not instantly go from 0 to a
           | constant, instead, it should grow smoothly, like pictured in
           | TFA. So you want a non-zero 3rd derivative, and possibly even
           | a non-zero 4th derivative.
           | 
           | Cubic splines of course give you a nice 3rd derivative. In
           | fact, you can't make a perfect circle using cubic splines,
           | because of that. Draw your device's shape in Illustrator or
           | Inkscape, and you likely make it Apple-like :)
        
             | pmahoney wrote:
             | See also "Why roller coaster loops aren't circular anymore"
             | 
             | https://news.ycombinator.com/item?id=32005421
        
         | yshklarov wrote:
         | That is roughly correct. For a curve with smooth
         | parametrization f(t) = (x(t), y(t)), with f'(t) [?] 0 for all
         | t, the curvature at the point f(t) is defined to be k :=
         | |(f'(t)/|f'(t)|)'| -- the magnitude of the first derivative of
         | the unit tangent vector. This is a nonnegative quantity, and is
         | well defined, that is, independent of the specific
         | parametrization of the curve (as legosexmagic said, you need to
         | do something like this to get a quantity independent of the
         | parametrization, but it is essentially a "normalized" second
         | derivative).
         | 
         | The curvature comb consists (it seems to me) of a normal line
         | segment at each point, whose length is directly proportional to
         | the curvature there.
        
           | yshklarov wrote:
           | Oops, my mistake: that is not the definition of curvature!
           | The outer derivative must be taken with respect to arclength,
           | rather than with respect to t.
        
         | legosexmagic wrote:
         | thats pretty much it yes. the reason they dont just say 2nd
         | derivative is that the derivative isnt a geometry property. you
         | can have two curves with the same shape but different
         | derivatives.
         | 
         | curvature only depends on the shape of the object.
        
           | phkahler wrote:
           | It's called C2 continuity.
        
             | yshklarov wrote:
             | Do you know whether it's usual nowadays in industrial
             | design to make curves that are actually smooth (I mean,
             | derivatives of all orders are continuous) and not just C2?
             | Or is it technically challenging for some reason, or not
             | useful?
        
             | jsjohnst wrote:
             | Actually, you only need G2 continuity for the reflection to
             | be continuous (yes, C2 is also G2 for regular curves).
        
             | kelsolaar wrote:
             | The Continuity of Splines: https://youtu.be/jvPPXbo87ds
        
               | harywilke wrote:
               | I came here to post exactly this excellent video on
               | splines by Freya Holmer. This discontinuity of
               | reflections effect is directly mentioned at 29 minutes in
               | chapter 4 on geometric continuity.
        
       | hbrn wrote:
       | > Apple doesn't have the patent on this.
       | 
       | But they do: D558,757 and D670,286. Don't people remember Apple
       | v. Samsung case?
       | 
       | https://patents.google.com/patent/USD558757S1/en
       | 
       | https://patents.google.com/patent/USD670286S1/en
        
         | dagmx wrote:
         | Afaik those patents don't describe continuous curvature, but
         | just general curved bodies.
         | 
         | Apple's use of continuous curvature in iPhones came around iOS
         | 7 iirc. I might be mistaken but I think they're subtly but
         | consequentially different subjects.
        
         | robertoandred wrote:
         | Your links explicitly refer to the complete designs of entire
         | devices, not a kind of curve.
        
       | [deleted]
        
       | whywhywhywhy wrote:
       | This is all very standard stuff in product design. It's more just
       | a surprise to UI designers because 2D design tools are very poor
       | and don't include superellipse as an option.
        
         | zeroimpl wrote:
         | I recall this being annoying for me as an app developer trying
         | to perfect the app icon. You upload the app icon as a square
         | image, and Apple applies the round corners when they distribute
         | it. I wanted to preview how it'd look on the App Store (back
         | when every app submission would take weeks to get approved),
         | but found the rounded corners from GIMP just didn't match. At
         | least they had stopped applying gloss effects by then which
         | totally ruined the colors.
        
       | rowanG077 wrote:
       | I have never liked this roundness in any product. It somehow
       | reminds of children toys. Apple has them. Most cars have them. It
       | just give this supreme baby toy vibe to me. I never knew what
       | it's called but this article finally explained it.
        
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       (page generated 2022-12-24 23:01 UTC)