Creating arm bones, the simple way.
 

Step 1
This is the most basic setup, and is used most often. If you're working on a game and have memory limitations, this is the one you want. It definitely gets the job done, although not very elegantly.

First, create the bones. You can either bring up the Bones Tools dialogue box, or go into the Create Panel/Systems and click on Bones. Start from the shoulder and work your way down. Make sure the hand is a separate hierarchy by right-clicking after creating the forearm and then clicking away from the little nub that Max automatically adds at the end of a bone chain. If you start the hand too close to the forearm it will automatically be added to the arm chain, and we don't want that.

Tip: Create all your bones in the same viewport to make sure that they will all have the same local alignment. This will save you trouble down the road. You can always resize and move them in other viewports later. And if you use the Right viewport, then when you add fins to the bones using the Fin Adjustment Tools section of the Bone Tools window, they will appear where you expect them to.

Step 2
Now we need to add the IK chain to bone hierarchy. Click on the nub (Bone03 if you've been following along correctly), go into the Animation menu on top, and down into IK Solvers, and choose HI Solver. You could also choose IK Limb Solver, which is specifically made to use on arms and legs. But I personally haven't used it a lot so I couldn't say what the real benefit would be. The HI Solver works in all situations, so that's what I use. It's also a big improvement over older versions of Max.

Step 3
Click on Bone01 to complete the chain.

Step 4
We need to attach the hand to the arm, so select the hand bone (Bone04), click on the Align tool, and select the IK Goal (IK Chain01).

Step 5
Configure the Align Selection windows as shown below. This will position the hand at the bottom of the arm, which is a good thing.

Step 6
Now we're going to align the IK Goal to the hand to make it easier to animate with. Basically, do the opposite of Step 4.

Step 7
This time click on all the rotation alignments.

Step 8
Link the hand to the IK Goal helper object.

Step 9
That's pretty much it. Now when you move the IK Goal, the arm will bend and the hand will move with it.

Step 10
You can also use the IK Goal to rotate the hand, which will save time when animating.

Step 11
Looking at these skinny bones doesn't really give you good idea of what you're animating or how the bone is oriented. We'll add fins to the hand to help with this. Go to the Character menu on top and select Bone Tools.

Step 12
With this window you can change all sorts of bone attributes. Scroll down to the Fin Adjustment Tools section, make sure that the hand bone is selected, and check the Side Fins box. Change the size to something that looks good.

Step 13
We'll also enlarge the IK Goal to make it easier to see and select. Select the goal, go to the Motion panel, scroll down, and increase the Goal Display size.

Step 14
Moving the arm around and watching it bend automatically is all well and good, but what if you want to make the elbow point in a different direction? This is where the Swivel Angle comes in. In the same Motion panel where you changed the IK Goal size, you can animate the Swivel Angle to change the orientation of the arm.

Step 15
Another way to do this is to add a Dummy object and use that as the IK Solver Plane Target. Create the Dummy object and place it somewhere behind the arm.

Step 16
Select the IK Goal object again, go to the Motion panel, click on the Pick Target button and select the Dummy.

Step 17
Now, instead of animating the Swivel Angle, you move the Dummy around to change the orientation of the arm. In some ways the Dummy is easier to animate with, but the Swivel Angle is more convenient. Try it both ways and see what you like.

Simple, effective, and easy to work with. This rig will get you 90% of the way there. But if you want that extra bit realism and a smoothly deforming model, check out the next two techniques.

Click here to go to the next technique...

Click here to go back to the "Arm" page...