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       #Post#: 12--------------------------------------------------
       Tangents, and why they should be avoided
   DIR By: Pam
       Date: May 20, 2021, 6:59 am
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       (and how hard it is to avoid them)
       A common term when discussing art and composition is 'Tangents'.
       These occur when masses or lines are grouped in a way that's
       visually confusing and hard to read. There are many great
       examples of tangents, and how to spot and avoid them around the
       place, but one of my goals is to be able to look at traditional
       technical artistic knowledge in the specific context of
       adventure games, because I think it helps to be able to see the
       problems directly in the medium you're interested in working in.
       With that in mind, I've compiled a list of examples, with the
       goal of showing a variety of types. Something I want to stress
       is that tangents happen to everybody - I recall watching a
       lecture about composition during which the lecturer noticed a
       bad tangent in one of his examples, and had to laugh and say
       that he'd hoped to avoid any. They happen to everybody,
       particularly as compositions get more complex, and it's always
       worth double checking once you've got fresh eyes and stepped
       away from a finished piece for a while. They'll still slip
       through, if you're anything like me, but a double check can help
       to minimize them.
       I've tried to make the tangents in these examples as clear as
       possible with the use of arrows, but towards the end of this
       post they grow quite numerous. It might be worth opening each
       image in a new tab, so you can see them at a larger size, and
       read along this way.
  HTML https://2.bp.blogspot.com/-up6I-CcB7a4/WKfb2FxRQaI/AAAAAAAAAzY/0iQz3h7mWB0k1kfehvnfjRZkxLEGu2qFQCLcB/s400/Discworld.png
       A great starting point is the banners in this scene from
       Discworld. Notice how the right edge of the banner indicated by
       the second red arrow aligns perfectly with the right edge of the
       column behind it. This flattens the banner terribly - it's much
       harder to read the depth, because it feels like it's a
       continuation of the column, rather than a separate form.
       Similarly, notice how the bottom of the flag to the left of it,
       as indicated by the other red arrow, aligns perfectly with the
       line running horizontally through the column. Once again, the
       continuation of this line makes it harder to read.
       In reality, none of the banners in this scene are placed
       particularly well against the columns behind them. The ideal
       goal is to have two object edges either overlapping by a
       substantial amount, or not at all, with a decent gap between
       them. Placing lines as close as they are here puts a scene at
       risk of tangents and near-tangents.
  HTML https://2.bp.blogspot.com/-D5M6gBVV1aI/WKfb5MWCLmI/AAAAAAAAAz8/IpnHw8IvVycpDri8GwAXZJ6g0_0jaKQVQCEw/s400/The%2BDig.png
       It's not just straight edges, either. Notice how in this scene
       from The Dig, the angled curve from the edge of the alien
       craft's cockpit follows on the same curve and angle as the edge
       of the foreground object that touches it. This can make them
       hard to read, as at a glance it can give the illusion that
       they're somehow connected. It's a particular shame when tangents
       happen in such abstract forms such as these, as there's no real
       architectural or practical reason that these forms align in this
       unfortunate way, and it would be quite simple to fix.
  HTML https://2.bp.blogspot.com/-3tq3Zvtjmr8/WKfb4R6vZxI/AAAAAAAAAz8/5QKQ4dxIt98iJC5bxkVJnTn2BAEbWyqzQCEw/s400/QFG.png
       In this scene from Quest for Glory you can see not a foreground
       detail but a background detail forming the tangent. The edge of
       the building ends, and clearly goes to a downwards wall, but the
       dirt in the background makes this much harder to read, and
       unless one looks closely, it's hard to see that the wall ends
       and the brown to the left of it is dirt. This case is
       particularly unfortunate because it's not just the fact that the
       lines meet in this way, but the colours match so closely that
       it's hard to distinguish them anyway.
  HTML https://2.bp.blogspot.com/-oTCUDrwOO1U/WKfb4NDgnpI/AAAAAAAAAz8/BzQPnXcCK4sxp2uYSBqEJkTCSjR15-X_ACEw/s400/Police%2BQuest.png
       Sometimes it might not be the background artist that made a
       tangent happen, but an object artist or someone else who placed
       the objects in the engine. In this scene from Police Quest, we
       can see two fairly unfortunate examples - one where the edge of
       the red police light just touches the edge of the wall, and
       another where the line of the car's front left fender runs along
       the same line as where the asphalt meets the concrete. Because
       the car is an object, not a painted in background element, it
       would've been very easy to move it up further, so that it
       overlaps these edges more completely, and these tangents could
       be somewhat minimized.
  HTML https://1.bp.blogspot.com/-rxj4J4c_k-I/WKfb3bX1tBI/AAAAAAAAAz8/xAsOvs5oXSousQ7OtEAMgrTrDcoTHvYSgCEw/s400/Gabriel%2BKnight.png
       Sometimes, though, it's much harder to avoid. It's hard to see
       how the two points where the wooden supports of the attic wall
       align in awkward ways with the balusters of the stair's
       balustrade. No matter how things get rearranged, putting
       repeating patterns in front of similar repeating patterns always
       runs the risk of forming nasty tangents like these. The one
       shown by the right arrow here is particularly bad, looking as
       though it's a recoloured part of the baluster, nullifying the
       depth that should be apparent here.
  HTML https://4.bp.blogspot.com/-I-VCDV9ALrQ/WKfb44tmOzI/AAAAAAAAAz8/NEKaH_U7MwIKVWLdRFblZqTitgUPsuO5wCEw/s400/Simon2.png
       This scene from Simon the Sorcerer 2 has some fantastic examples
       of tangents that really confuse the eye. The tangent shown by
       arrow number 1 shows a stand whose leg should read fairly
       clearly - but the fact that it meets at another junction of
       angles makes it quite hard to see depth here, compounded by the
       fact that the colours are very similar. The lines at arrow
       number 2 have the same problem, to an even worse extent. The top
       of this stand genuinely looks like part of the edging of the
       rug, and is even the right colour to be, and meets it in two
       places. This is a very beautifully bad set of tangents, and very
       indicative of how confusing they can be to the eye.
       Arrow 3 shows how different colours reduces the impact somewhat
       - the bases of the chandeliers runs directly along this wooden
       trim, but because they're so different in hue and lightness,
       it's much less confusing to the eye. It's still worth avoiding
       tangents like this, though, because so much more depth can be
       achieved by overlapping them more or less so that the lines
       don't run along each other. The fourth arrow doesn't so much
       show lines touching as it shows two areas of the same colour
       touching in a way that they bleed into each other a bit. It's
       not as bad as the first two examples here, but still misleads
       the eye a little.
  HTML https://3.bp.blogspot.com/-VsybSzY2hxA/WKfb3yUDp0I/AAAAAAAAAz8/stpiPOI8BnsU8UjHRroYOiOoCijENqVEwCEw/s400/King%2527s%2BQuest.png
       This scene from King's Quest 5 shows tangents in a more organic
       setting. The first arrow indicates what should be two separate
       root structures, but the way they diverge from the same point
       makes it look like a single root split into 2 parts. Because
       they follow a similar angle, it's not that easy to tell the
       foreground shape from the background shape. Similarly, arrow two
       indicates an area where not only do two trees meet with a
       horizontal curve that looks like it continues from one to the
       other, but the rear root sits upon a path that matches it so
       closely in colour that the form gets lost a little. Just above
       the second arrow we see two branches, from two separate trees,
       appear to join due to a nasty tangent.
       At point three, we see a small tree branch ending right where a
       pair of small tree trunks start. At a glance, it looks like
       these distant tree trunks are a continuation of the branch, an
       unfortunate illusion that ruins the depth somewhat by making it
       hard ot judge where the tree trunks start. Similarly, point 4
       indicates two more tree trunks whose bases are obscured by
       shapes in front of them. Again, this makes it hard to judge
       their distance, and therefore flattens the image somewhat.
       The fifth arrow points to a wonderfully clear example where the
       tip of the smaller foreground tree occurs right on the angle of
       the larger  one, making the two forms merge into a single form
       at a glance, another unfortunate ruining of depth.
  HTML https://3.bp.blogspot.com/-hcW8w_b0ZtY/WKfb3cSxtjI/AAAAAAAAAz8/fdT5n_AD638v0muJadW2vaKsBtxaoa5QwCEw/s400/Curse%2Bof%2BMonkey%2BIsland.png
       As we move into more complex forms, such as those in this scene
       from The Curse of Monkey Island, the possibility for tangents
       increases. The edge of the chair at arrow number 1 aligns in a
       way with the stool behind it, and with such similar designs,
       that the depth here is lost once again. At arrow number 2 we see
       the curve of a lamp's brasswork touching several lines of the
       shelf, helping to make what should be a fairly deep, solid
       feeling design somewhat flat.
       At arrow number 3 we can see the edge of the cabinet on the
       counter matching the edge of the shelf behind it perfectly,
       which makes the shelf feel like it's part of the cabinet here.
       Another flattening effect, as is common with tangents. At number
       4 the other edge of the cabinet runs along similar lines to a
       portrait behind it, cluttering up the grouped mass in a way
       that's hard to read and doesn't feel very natural.
       Arrow 5 doesn't actually indicate a tangent, but instead where a
       tangent nearly happened. The top of the chair's backrest and the
       edge of the bar are close enough that it would've probably been
       improved had the chair been moved further to the right to avoid
       this very close proximity. Arrow 6 shows a chandelier touching
       the edging similar to the earlier example in Simon the Sorcerer,
       but here it only touches in a couple of places. Nevertheless,
       it's an unfortunate meeting, and would've probably felt deeper
       and more easy to read had the chandelier overlapped the edging
       more boldly.
  HTML https://4.bp.blogspot.com/-VyLCc7c5U-Y/WKfb20lU0xI/AAAAAAAAAz8/FuTuqhfvS_YEV3GCjgA9W4jCArZKHWHWQCEw/s400/BS1.png
       Here in this scene from Broken Sword we have similar levels of
       overlapping shapes, and once more feel the presence of tangents.
       At the first arrow the top of the wire mesh panel aligns
       perfectly with the trim on the wall, meaning the top here is
       basically lost, and hard to read. At point 2 we see a non-lit
       light fitting touching both the ceiling trim on one edge and a
       lit fitting on the other edge, flattening it somewhat.
       The third point indicates the end of a curve in the chandelier
       that lines up perfectly with the edge of the ceiling trim.
       There's a couple of similar spots in this fitting where the
       curves touch the ceiling trim lines in similarly close ways, but
       this is the strongest, clearest example of a tangent. The fourth
       point is particularly unfortunate, where we see the curve of the
       arched doorway completely masked by the angle running across it.
       The fact that this angle is the same colour as the elements
       behind it can also give the illusion that the vertical bars in
       the foreground are connected to this angled foreground piece of
       wood, rather than the curved feature it's hiding. A lot of depth
       and readability is lost this way.
       Arrow five indicates another point where a light fitting is just
       touching the edge of the wall trim, particularly frustrating
       when there's so much empty space to the right that the light
       could've been placed instead. As with most tangents, this
       could've been improved by moving it to either the right or the
       left - grouped masses should overlap boldly, or not at all. The
       sixth arrow shows the edge of the desk just overlapping the edge
       of a file cabinet - not enough to really flatten the image, but
       enough to make me wish the desk ended just a handful of pixels
       before, considering how much blank wall is between the cabinet
       and the shelf.
       I deliberately tried to pick well loved, well known games here
       that have great art to prove just how hard it is to avoid
       tangents. Hopefully seeing these examples will show or remind us
       of the problematic nature of accidentally working tangents into
       a composition, and give some idea about what sort of scenarios
       they might crop up in. Knowledge on how to identify problems
       such as these is the first step in knowing how to solve the
       problem, and once we've gotten used to looking for tangents,
       it's much easier to identify them and, hopefully, solve the
       problems they present our compositions with.
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