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Nov
08

Why The Single Vanishing Point In 1-Point Perspective Is Always Dead Center

Or, maybe instead of “is always,” I should say “should always be.” You certainly see plenty of drawings where it’s not. But, hear me now and believe me later: this is just plain wrong–or at the very least, unnatural looking.

This came up in class today, so I thought I’d do a quick post about it. A student posted a drawing in one point perspective with the vanishing point (hereafter: “VP”) about 2/3 of the way toward the right hand side of the page. Another student noted that it looked odd and wondered why. The class is not a perspective class, but I thought it was worth at least touching on. For obvious reasons, I’m not going to use my own student’s drawing for an example, but here’s a random one I grabbed via Google Image Search:

As you can see, I’ve traced back some orthogonals and located the single VP on the horizon line. It’s obviously way off-center.  Now, the drawing looks “correct” in the sense that all of the non-horizontal lines are converging to the common VP as they should, but there’s definitely something odd about this image–and it all has to do with where our imaginary viewer of this one point perspective scene is positioned.

So, Here’s the the real life situation that produces a one point perspective view:

(Sorry about the slap-dash drawings. They’d have been more polished if I had known I’d recycle them for a blog post!)

So, seen from overhead: there’s you, the viewer, looking at an empty box that’s parallel to your line of sight. (If that box were not completely parallel to your line of sight, you would start to see a bit of the outside surfaces of the box which would now give you two vanishing points and you’d be in two point perspective.)

When you draw a representational drawing (as opposed to an abstract drawing) you’re trying to replicate something that one would naturally see through ones eyes. That’s what representational drawing is: it’s an attempt to represent (or replicate) something as a viewer would really see it.

To do that, what you’re doing is taking a “slice” of an (imaginary) viewer’s field of vision and transferring it to your canvas’s picture plane:

When you do that, here’s what you get:

If you set up a drawing with the VP off-center like I’ve framed off in red here, you’re lopping off a part of the viewer’s field of vision and creating a view that’s not anything that a real person would ever possibly see in the real world…

…. because what you’re doing is grabbing an odd side portion of the viewer’s field of vision and you’re leaving off a corresponding portion of it on the other side:

And that’s exactly what’s going on in that example drawing. The line of sight of the (imagined) viewer of the scene has to be directly lined up with the VP; and since the human field of vision is symmetrical and extends equally to our left and right, that viewer would be seeing as much visual material to the left as to the right:

Or put another way, sort of reasoning from the other direction: what one point perspective is is a situation where an object’s vanishing point falls directly on the viewer’s line of sight. Since the viewer’s field of vision extends equally to the left and to the right of the line of sight, the VP in one point perspective is by definition in the center.

Now… that said, yeah, you often see drawings where people just arbitrarily place a single VP somewhere on the page and then start drawing. These will always look odd and unnatural, though, for the reason outlined above: that’s a view that would never naturally occur. You even see it in photographs that have been cropped after the fact.

It’s not a big no-no and frankly you see people do it all the time… but it’s worth understanding and–in my opinion avoiding–situations where the VP is off-center in one point.

9 comments

  1. Isaac says:

    But what if the panel represents only a small part of the field of vision, “cropped” off-center? I’m imagining a close-up, for example, of something on a high shelf, with one-point perspective (and a vanishing point not even within the panel, but below it and to one side) indicating that we’re looking up at what’s visible in the panel.

  2. Ben says:

    @Just backing up a bit: perspective is a tool that’s most applicable to a naturalistic style. If your style is closer to James Kochalka or David B. or whatever, it’s not something getting worked up about. On the other hand, the more realistic one gets, the more important it becomes.

    Some of the situations you describe there, though, don’t sound like things that are really call for anything non-kosher perspective-wise. When you talk about “part of” the field of vision or a “cropped” view, I think what’s really going on is just a close view of something; you’re not getting a cropped part of a larger field of vision, but rather a full field of vision that’s fully taken up by a single object–a “close up” to you film terminology.

    I’d love to see an example of the sort of panel you mention here, though.

  3. different perspective says:

    As an example of what I assume Isaac is talking about I’d use the the links below as examples of off center one point perspective.

    http://www.friendsofart.net/static/images/art2/mary-cassatt-lydia-crocheting-in-the-garden-at-marly.jpg

    http://www.aiwaz.net/uploads/gallery/disputation-of-st-stephen-1189-mid.jpg

    Using a vanishing point that is off center is more dynamic in my opinion.

  4. Ben says:

    @different perspective – I completely agree that the centered VP is pretty un-dynamic. The way to avoid that, though–in a way that mimics human vision–is to use two-point perspective, not one-point with a lopped-off picture plane. Given that there’re no objects in that first image that have 90° angles, it’s hard to tell exactly what’s going on perspective-wise. The second one, though, is for sure one-point with an off center VP. It’s exactly the same sort of case as the image I marked up in the post: it’s an image that’s depicting just the left-most part of the viewer’s cone of vision and–to my eyes anyway–looks odd because of that.

  5. Eric says:

    I believe there’s a comic example in a recent issue of Daredevil — I believe #5, looking down the gangway of a boat. I can only find issues 1-4 at the moment, unfortunately.

  6. Eric says:

    Found it: http://img215.imageshack.us/img215/5791/daredevilperspective.png

    Maybe?

  7. Ben says:

    @Eric – Yeah, that’s a pretty good example. Like I said in the post, it’s something you see fairly often despite it not being technically 100% correct. The more off-center the VP the odder it looks to my eye. So, that Daredevil panel doesn’t look egregiously odd to me.

  8. Eric says:

    I can see DP’s argument that it makes for a dynamic image, and I think it kind of works here because it’s used sparingly — the perspective is correct (mostly two-point) in the rest of the book.

    Visually, it reminds me of the “dolly zoom” seen in film.

  9. Ben says:

    @Eric – The “dolly zoom” comparison is a good one. Like an off-center VP in one point, it’s somewhat unnatural… but if used sparingly it’s not a problem.

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