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So, now let's look at a part of the skeleton that's cylindrical. We're going to look at
the left leg, the upper leg bone, the thigh bone or femur
Let's start out by thinking about what we know about the cylinder.
There's going to be a background and against the background we'll have a highlight
In this case the cylinder isn't sitting straight up and down, it's at a bit of an angle
So, as I take my soft eraser and erase in a highlight, I'm going to have it come down
at a bit of an angle, to kind of match the femur and then, the light is coming from above and
the side so when it gets to the fattest part of the femur that is closest to us it has
to travel in a straight line; it can't bend around to the side so there's a shadow there
We'll put that in And there's a smooth transition because the
femur is cylindrical. We don't want a harsh edge between the shadow and the highlights
so I'm going to experiment with different ways of softening the edges, blending the
edge Now, the femur is a little bit of an irregular
shape so I'm going to try and capture a little bit of that. I'm going to notice that it's
a little bit wider in some places and that it changes direction a bit
When we get down here into the knee, for example it flares out quite a bit
When we get up here, closer to the hip socket, there's some different structures that poke
out a little bit. These are places, attachment points for muscles and the head of the femur
at the very top is kind of an ovoid shape where your hip joint is
So now, I'm going to work in some more details of the light and shadow so I need the front
of the femur to be bright so that it looks really bright I'm going to darken the background
a bit I don't really want a dark line here instead
I'm going to try to have an intermediate gray against a very bright area and then the intermediate
gray over here again and against a much darker shadow area
I want the shadow to look like it's on the femur not on the background so I'm going to
rub toward the center of the femur instead of rubbing it into the background
Here the femur flares out so the bright area flares out and this interesting variation
where there's an attachment point comes out here. There's an attachment point that faces
away from the light here under the ball of the femur
Because the bone is not a perfect cylinder the way the bottle was, it has a lot of irregularities
we could start to put some of those details in
All these irregularities are created by the muscles and tendons that attach to your leg
bone So as I put more of these details in, I'll
get a drawing that looks more organic and natural
Down here at the bottom we have a curve, just like we had at the curved bottom of our bottle
And I could develop more detail if I have the time and the inclination but I think that
will give us a basic idea of how to apply thinking about the light and shadow on the
cylinder to a cylindrical part of the body. We have our dark, our light, and our background.
We have our dark area, our light area, and our intermediate area