Now drag this icon up to our main toolbar to place it there. I prefer to add it to our linking tools, like so (Fig.08).
It is the greyed out tool on the right. It is greyed out because we don't have anything selected at the moment that can use IK.
Time to IK!
Select on either of the thighs and then select our IK tool. You will see the IK tool become active as soon as you select on the thigh.
With the IK tool active, you will see a dashed line following your mouse, waiting for you to pick the end of the IK chain, so select on the foot under the same thigh you first selected. Once done, you will see a blue cross appear at the pivot point of the foot. Max automatically selects this object for you so go ahead and move this object up to see the result of your IK.
Don't forget to undo to put the foot back where it started (Fig.09).
Leg IK in action!
Do the same thing for the other leg now.
Then do the same thing for each of the arms. This time, first select on the Upper arm, then select the IK tool, and then choose the Hand. Remember to test it out when you complete it and then undo to put it back where it was (Fig.10).
Arm IK in action!
We'll get more into detail on some of the finer points to using and adjusting the IK in a minute.
Once you have completed this for both the legs and arms it is time to work on the spine.
We are going to do the spine a little differently because it reacts differently than the arms or legs. You'll notice that the arms and legs cannot possibly bend in an unnatural way. The joint doesn't allow for bend angles to exceed 180 degrees (this would be the same as completely breaking your arm), but obviously our spine has a lot more of a range of motion than this! So we need a new solution.
This is exactly what it sounds like: it is an IK solver that uses a spline to drive the motion. Fair enough? Let's take a look.
Switch to your left view. Now go to the Create panel, pick on Shapes and Line. What we are going to do is draw a line that will represent our spine. Before you start we need to make a quick change concerning how the spline is created, find the Creation Method rollout and make the following adjustments (Fig.11).
Now, as we draw our line, Max will automatically smooth out our line for us.
So off to the side, starting from the hips (very important that your first vertex is made here) create the following shape (Fig.12).
Notice that there are only 3 vertices on this line: one for the hips, one for the centre of the spine and one for the top of the spine. These will be our pivoting angles for the spine. If you want more on your characters then make more, just remember the more vertices the more objects you will need to create to control these points.
I made you create the shape off to the side for simplicity so as to avoid any confusion. You can perfectly well create the spline right over top of the body and therefore eliminate the following step.
Now move the spline into the body, like so (Fig.13).
Remember this is the spine of the character so its position is very important.
Okay, make sure that the position is correct in the front view – it should be perfectly centred. Then select the hips. Now, we add the spline IK solver, go up to Animation > IK Solvers > Spline IK Solver (Fig.14).
Now, with the dashed line following the mouse, pick Man_spine_3 (if you leave the mouse over an object for a second it will tell you what object you are about to select). Now it needs you to tell it what spline to use so, finally, click on the spline we just made. The whole spine will adjust to fit the IK, so don't worry if it moves – it's supposed to.
Once the spline IK is complete, Max will create helper objects around the vertices of the spline so you can control the vertices easily (Fig.15).
If your version of Max doesn't do this for you, just select on the spline and go to the Modifier tab, apply a Spline IK Control modifier and then click Create Helpers.
Okay, almost done!
All we need to do now is finish creating objects that will help us animate.
Everything we have done up to this point has set us up for the actual rig.
Animators want the easiest way possible for manipulating a character, they do not want to deal with objects that are hard to select on or that give no real access to multiple objects at once, which is why they want a rig.
Keep in mind that every rig will be different, but there are some things that are basic needs. A rigger in the industry will be responsible for making very complicated rigs that are intuitive and easy to manipulate, but here we are going to look at the basics.
What we will do is follow suit with what our spline IK did for us – it made helpers so that we can access the vertices of the line very easily. Mainly we will make objects that help us control our character. All of this is done simply by linking one object to another so you shouldn't have any problem with it if you have made it this far.
Let's start with the spine first.
First off, go to the Display panel and check Geometry under the Hide By Category rollout. This will hide all of our character mesh so that all we are left with is the actual "rig” at the moment. All of the pieces you see now are what currently control the character. So this is where we will start (Fig.16).
Now, back in the Create tab, create a Circle around the centre of our world, like so, and then go to the Modify tab, open the Rendering rollout and check the Enable in Viewport box. Now our spline looks like geometry – it is now easier to see (Fig.17).