Turning Archive 2006

My word on boxes and triangles (very long)

Russ Fairfield
>I have stayed out of this discussion because I didn’t have anything to contribute, but being one who is never at a loss for more words than are necessary, here goes with what I think about shapes and design.

There are several factors of good design that have been missing in this discussion. Some of them have been alluded to, but none of them have been discussed – fair curves, balance, the framing effect, the 2D effect, and the fact that we are doing something.

My observation is that there are two types of student, just as there are two types of woodturners – those who can recognize a good shape, and those who don’t. The ability to “get it right” is a gift, a natural talent, and there are very few of us who have it. We say these people have “artistic talent”. There may be no more than 1 in 10, if that many. For the student who has that natural ability, the rules of the Golden Mean, Rules of 3rds, Keith’s Triangles, or anything else, are an explanation for what they are already seeing, and puts it into some understandable context and perspective.

For the other nine who don’t get it, there is no amount of rectangles, triangles, or anything else that will make them see what that is beyond their ability to see. These are the people we tell to read the books on pottery or sculpture to learn what makes a good form. What we are really doing is showing them a picture and telling them, “This is what a bowl should look like. Copy it”, or “This is what a vase should look like, Copy it”. And, there is nothing wrong with that either, it’s just that we shouldn’t confuse their learning “by example” with those who are learning to “reason”.

The Golden Mean.
3000 years ago the Greeks discovered that there was a ratio that made a pleasing shape. It simple stated that, “The lesser is to the greater as the greater is to the whole.” In mathematical terms a rectangle whose length is 1.618 times its height is a pleasant shape to the human eye. It took 3000 years before an ophthalmologist discovered that was the aspect ration of the human vision without parallax or distortion at the edges. Of course it was a pleasing shape to us. It was a comfortable fit.

Meanwhile, this has become a means for defining the classical shapes, and why they might be more pleasing than others.

The Rule of 1/3’s
I discovered this rule over several years of turning trees into things that are round. Bits and pieces of information from other sources told me that a good foot on a bowl was 1/3 of its diameter, that a curved form should have its major diameter at 2/3 up from the base, and that the height should be 1/3 or 2/3 of the diameter. Along the way I discovered that a base that was 2/3 of the diameter also worked for a more stable bowl, that the major diameter could also be 1/3 up from the base, and that the diameter could also be 1/3 or 2/3 of the height, and that the diameter of a proper vase was 1/3 its height. I applied the rule for the shape of the bowl on a goblet, and the height of its stem, and the diameter of its base. My biggest discovery was that there were more things outside of this rule that still looked good than within it.

I use this “rule” as a teaching tool, not because it is the ultimate definition of what looks good, but because it gives some chance of success to those who don’t have a clue where to start. I sus[ect that others use it for the same reason.

Fair Curves.
A “fair curve” is one with no abrupt changes in the curvature and no flat spots. Like the laminar flow of water around the hull of a sailboat, our eye can follow the curvature from the base to the top without interruption, and we will call this a pleasing form or curve. However, there is also the curvature with a total interruption of the flow, our vision becomes detached, our mental picture of the object becomes confused, and in this chaos we discover something that forces us to think as we try to put it back together. There is a lot of work that is in between, and we call it “confusing’” because it is neither fair nor foul.

Keith using the chain to form a family of catenaries within the triangle only insures that the result is a fair curve. There can be do disruptions in the form of a hanging chain.

Balance describes all of the elements that make up the object being in harmony with each other, and in their proper perspective with each other. The foot is not the dominate feature of the bowl, the stem is not too big for the goblet, the finial is not the dominate feature of the lidded box, and the various shapes are complimentary to each other (unless their clashing is the desired effect).

The 2-Dimensional Effect
Whenever we make a drawing of anything, we are taking a 3 dimensional object and reducing it to only 2 dimensions. Using a bowl as an example, the drawing makes it into a hard edged form, when it is a soft edge that is defined by a curve that is going away from us in the 3D world around us. That bowl will usually look very different in real life than it will on paper. We can reduce this hard-edge effect in a photo, by making the outer edges slightly out of focus, and thereby more duplicating what we would see in real life. When we see a photo of a bowl with sharp edges, we see it as artificial and having been enhavced because it doesn’t look “natural”.

The Framing Effect
We put a frame around an object to concentrate our attention on the object. Put a picture without a frame on the wall, and we see the wall. Put a frame around it and we see the picture; and not only that, the picture is brighter and will have more detail. We have removed the background from our vision.

Putting boxes and triangles around a turned object has the effect of framing the object to focus our attention. We could argue that the shape and proportions of the box can make a difference in what we see, but what we are really doing is focusing our attention on a specific object and diminishing its surroundings. That lets us see the object as it really is, and without any influence from its surroundings.

The Effect of Doing Something
This could very well be the greatest effect of them all. Everything we do is influenced by the fact that we are doing something. In this case we are actually trying to come up with something that might look “right” before we start making shavings. We are applying pencil to paper, and we are trying to use all of our insight as to what might be correct, our memory of what we were told was a good shape, and all of our likes, dislikes, and prejudices, to determine the shape of something. When was the last time that anyone put this much emphasis on the shape that they were developing in their mind, or copying as the case might be.

The Tompkins Triangle
You guys had me dreaming about shapes, rectangles, and triangles last night, and that might have been a good thing. I see Keith’s triangles as being a useful tool within the context of all of the above that I have discussed. As a stand-alone tool, it is lacking because there are too many cases where it won’t fit. However, within the context of the “Golden Mean”, where the vertical and horizontal legs of the triangles have the ratio of 1.614, it is good way to get from the shape of a box to a bowl. I would suspect that there are reasonable limits to the shape of the triangles. I can see that a 3 to 1 or a 3 to 2 ratio of vertical to horizontal in either direction works because it fits the rule of 3rds. I can also see that a 3-4-5 triangle also works very well because it is easy to draw.

Most of all, it forces the student to think. Forcing us to think before we act is always a good thing. It Keith can use his method to do that, more power to him. But, we have to remember that thinking about the shape is the same thing that these other rules are doing. We must also recognize that any new rule must also fit into what has gone before, or it must refute what we already know to be true.

The 80 degree triangle was used to refute the method, and Keith agreed that it wouldn’t work. I disagree. It does work. A fair or centenary curve can be placed within a tall skinny pair of triangles by holding the ends of the chains closer together. The only limits are the length of the chain, our ability to draw the curve, and our ability to turn it on the lathe. I have seen such tall shapes done in silver, but I don’t personally care for skinny trumpet-shaped vases that are 3’ tall and 3” in diameter. Others might.

That same 80-degrees could also be used in the flat direction, and a very broad and shallow platter would be the result. Again, it can and has been done in silver and other metals, but not done well in wood.

The problem I see in doing these extremes in wood is that it is almost impossible to make them into a “fair curve”. Besides the technical aspects of the turning, and the movement of the wood, every deviation becomes the more visible as the curve approaches a straight line. We start seeing deviations from the line that are as small as 0.005”. As the pieces get larger, the parallax and edge curvature of our vision begins to distort the shape and we no longer find it a pleasing one. If we are looking at a picture we see that the curvature of the lens has distorted the lines of the curves.

There have also been disparaging remarks made about things with straight sides and square bottoms. There are a lot of very nice boxes in the woodturning archives that fit this shape, and we see them as being one of the highest forms of the woodturning art. Not liking straight sides is an opinion that has nothing to do with whether it fits anyone’s “Rule”. Spheres are also pleasing shapes that don’t fit any of the “rules”.

So, that is all I have to say on this topic. There is a lot more to this “vision thing” than I can cover in this one message or Keith can cover in one short demonstration or pamphlet. All we can do is bark around the fringes, and that might be our problem.

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