The Lower Body


The Lower Body

Next we will look at how Kila's lower body reacts when we move her legs into extreme positions. The main area we will be looking at is where her legs join to her torso.

Setting Up the Lower Body Skeleton

For our work on the lower body, we start by creating the skeleton that will drive the legs.

You only need to look at one of her legs, since they are more or less identical in construction. Just remember that if you make any changes to the left leg, you will have to copy these changes across to the right.

1.

In the side view, switch your display to wireframe.

2.

Create six joints at key points in the leg and foot. As illustrated in Figure 6.25, the first joint should be just below the waistline, at the top of the hip. This will be followed by joints placed at the hip, knee, ankle, the ball of the foot, and finally at the tip of the toes.

Figure 6.25. Create the joints for the leg.


3.

Switch to the front view, and adjust the skeleton so it lies down the center of the left leg and foot (Figure 6.26).

Figure 6.26. Position the joints down the center of her leg.


With the skeleton in place, we can now bind it to her trousers using the same procedure as before.

Lower Torso Weight Painting and Testing

Let's see how the hip area of the torso looks when it is influenced by the skeleton.

1.

Before you begin properly testing the left leg, make sure the entire right leg and the top of the trousers are fully influenced by the first joint (Figure 6.27). This should be called joint5. You do this to pin down the leg you are not working on. If you don't, it will move when you rotate the joints and could become distracting.

Figure 6.27. Fully weight the leg you are not working on to the first joint.


2.

So let's see how things look when we bend the leg. First rotate the leg forward at the hip joint (Figure 6.28), and take a look at how it deforms.

Figure 6.28. The initial deformation looks fair, but it needs some work.


3.

Initially it's not looking too bad; now let's paint some of the weights to try and smooth out the area. Begin by fully weighting the bulk of her thigh to the hip joint.

Then go in with the smoother brush and, using Replace, smooth out her backside and the crease at the front. Figure 6.29 shows that we have a good deformation, so there doesn't seem to be any need to add any polygons here.

Figure 6.29. Tweak the weighting around her hip to smooth out the area.


4.

Take a look at how the hip deforms if the leg is rotated back (Figure 6.30); it reveals a few minor problems but nothing the weighting can't fix. The same is true when the leg is rotated out to the side (Figure 6.31); it will look better with some tweaking of the weights.

Figure 6.30. Rotating the leg back


Figure 6.31. Moving the leg out to the side


There are a few areas in the lower torso area that pinch and deform incorrectly, but these can be fixed by spending some time on the weighting, something we will cover in Chapter 14, "Final Character Deformation."

The thigh doesn't need any additional geometry, so let's move on.

Knee Weight Painting and Testing

Our next painting and testing site is the knee. As you have done with the other joints, rotate it to see how it looks initially (Figure 6.32, top).

Figure 6.32. Bend the knee and paint the area to fill out the shape.


By now, we know that we will need to adjust the weighting to get a proper shape. Make sure the lower leg is fully weighted to the knee, and then fine-tune the weights around the knee to retain the shape of the leg. The resulting shape should resemble Figure 6.32 (bottom).

The knee area looks fine; like the hip area, there's no additional geometry needed.

Up to now we haven't had to make any alterations to the main legwhich is good because it means we don't have to do anything to her right leg. As you can see in Figure 6.33 you can now deform almost all of the limbs.

Figure 6.33. Almost all of the limbs can now form correctly.


Foot Weight Painting and Testing

The final area to test in the leg is her ankle. Judging by the topology, this, too, will be fine; but you have to be certain before moving on to the next chapter. So let's take a look.

1.

First, reset the joints in her leg by right-clicking the joints and selecting Assume Preferred Angle from the marking menu.

2.

Go into wireframe mode, and this time select both the ankle joint and ball joint. We don't need the upper leg joints to influence her foot, so there's no need to select them or the tip of her toe.

3.

Hold Shift and select the mesh that makes up her foot, then bind them (Figure 6.34). In the Smooth Bind options, make sure Bind To is set to Selected Joints, or the foot will be bound to the entire skeleton.

Figure 6.34. Select the ankle and ball joints before selecting the foot for binding.


4.

As shown in Figure 6.35 (left), rotate the ankle down and the ball of the foot up, so that Kila is standing on her toes. Then go ahead and edit the weighting information on the foot. We need the back of the foot weighted to the ankle joint, and the front of the foot to the ball joint (Figure 6.35, middle).

Figure 6.35. Work on weighting the foot.


5.

Next, work on the base of her jeans leg, making the very bottom fully weighted to the ankle joint before gradually smoothing it out up to her shin area (Figure 6.35, right).

The only area that is a concern now is the underneath part of her shoe, mainly the front sole. The polygons are laid out now so that the base appears concave when the foot bends. Adjusting the topology as shown in Figure 6.36 will easily solve this, but we will need to do it when we detach the geometry from the skeleton. In addition, notice that we can reduce the sole, removing the vertices that run down the middle.

Figure 6.36. Adjust the topology of the sole as shown, to remove the concave look.


6.

We are now happy with the way the lower body deforms, so let's detach the geometry from the skeleton. First reset the joints in the arm and leg so that they are back in their original positions. Then select the geometry and go to Skin > Detach Skin.

7.

Now we can quickly fix the sole of the foot. First hide the joints by going to the view panel's Show menu and deselecting Joints. Then work on the foot until you have the sole looking similar to Figure 6.37 (right).

Figure 6.37. Optimize the base of the foot.


After finishing your work on the lower body, make sure you delete the history from each piece of geometry.