Often when we as artists begin to draw, paint, or sculpt, either traditionally or digitally, we overlook simple hidden principles, which, once revealed, make themselves evident everywhere in the world around us. A prime example is the simple but powerful figurative concept of Opposing Curves. Artists have been employing this principle for centuries under different names and guises ~ but if we look at the history of Figurative Art, we begin to see abundant evidence of the concept of Opposing Curves. Opposing Curves is no more complex an idea than that curves in nature are rarely if ever related to one another as are parentheses ( ), but that rather they are always offset from / or opposed to one another like the curves in the double helix of a strand of DNA. We as humans are structured around the principle of movement, and curves allow us to move in a way which is efficient and economical. As with plants and trees, so with human beings – we are built with curves, not straight lines, so as to allow us to move more efficiently. Therefore, when drawing the figure, the principle to keep in mind is simple: Opposing Curves. A simple rule to remember is that we can create the illusion of human form with a few swift offset curves, but we will never create such an illusion (or we will create a poor one) with curves that look like parentheses ( ). As an example, let's consider the following reference photo (as provided by Hong Ly), and analyze it in terms of Opposing Curves.                                                             If we do a simple tracing of the image, we find that form is created by pairs and sets of pairs of curves in a very predictable, call and response fashion. Good curves don't leave other curves hanging - in other words, curves in the figure - both contour (exerior) and interior curves act as trapeze performers in an all-out attempt to build form. If we take the analogy of curves as perfomers, they never drop their mate - if they do, then the show's over. Curves also never curve inward ~ curves are always convex, and never concave. Artists, particularly when they are starting out, draw curves which scoop inward, toward the interior of the form - when in fact, form is created by a series of (sometimes minute) convex curves. This mistake is made by artist most often around the area of the ankle. Artists should never use Parentheses ( ) curves to indicate form. The form which results from using perfectly parallel curves is a vase, not organic form, as human form is organic and rarely perfect in its symmetry. Instead, aritsts should use Opposing Curves, or Offset Curves, to generate Form. When drawing, painting, or sculpting, artists should try to think around and across the body instead of simply down one side and then up another. The sides of the body must relate to one another in order to visually make sense as an organic whole.                                                                     Here is another reference photo (as generously provided by model Ron Eyre). Here opposing curves are even more evident in the contrapposto of the pose - the legs are shifted, with most of the model's weight resting on his right leg - resulting in the upper torso shifting first towards the model's left, and then back again towards his right, to compensate. Notice how apart from there being a number of small curves making up the various body parts - torso, legs, arms, etc. - there is also a major theme happening in the figure which is about Opposing Curves. The whole of the models' left side can be simplifed as an arc, and the whole outside length of the model's right leg can be simplified in terms of two arcs which act in opposition to the thrust of the upper torso. This is the idea of the pose, and the idea is bound up with the concept of weight, which, here, as in all depictions of form, we would describe simply in terms of curves which oppose one another in a manner which is offset.   In this simple traceover, we can see that it is not necessary to draw every pore and hair in order to convey the total sense of human form. What is needed rather is a cohesive and comprehensible set of Opposing Curves which act in conjunction with one another to steadily build form. Every piece of every member of the body must be thinking of everything else - there is no part which is separate or isolated from the whole. Curves are the lifeline of this relationship - as one thing shifts, all things must shift with it in accordance with the principle of the unity of the body. Thus, what happens to each member and each curve of the body, has a ripple-down effect and changes every other part accordingly.

Here I've included a WIP painting done from the first reference photo in which the Opposing Curves of the figure are exxaggerated.                                               Here I've included a WIP of a portion of a painting done from the second reference photo to demonstrate that in the area of the ankles especially, it is important not to scoop out great quantities from the backs and sides by erroneously drawing them with concave curves. Upon close examination, even the most concave of curves is really a group of smaller convex ones.                                     Here I've included charcoal drawings done from photo reference of a runner (left) and from a Master Drawing (right) to demonstrate the use of Opposing Curves. The challenge in any figurative work is to get the interior of the form to work successfully with the exterior of the form in one organic whole. This is no simple task, and has thus far taken me years to come to grips with on even the most basic level.                                             Here I've included a number of my traditional copies of Master Works to demonstrate the use of Opposing Curves. To my mind, the artists who most successfully employed their use and who cannot be surpassed are Michelangelo and Rubens. I think it is a great exercise to copy from their works, in order to learn how to see as they did, and to test one's talents (however limited by comparison with the greats) as one can only improve, or even see that one needs to improve, by testing onself against the best artists of history. Related links: Rebecca Kimmel's Web Site CG Society Forum Hong Ly's Web Site

非常好的资料 只可惜少了点！谢谢！！！

建议来点互动的主题 这样或许会热闹点：）

大家在做这类的东西时，建议学习伯里曼的人体结构，不要太写实，略显夸张一点，但又很实在

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