Tutorial: Serenity Strut Rigging

Serenity Strut Rigging Tutorial

This tutorial assumes you know the basics of 3ds Max, and that you have had a little practice with Bones.

Scroll Down for the HTML Tutorial.

Overview

No, this is not exactly like the landing struts on the Serenity spaceship, but it is the same idea. The point here is to show how a bones rig can be developed that will function in a similar fashion, as a landing strut that absorbs the impact of a ground landing. This image shows you the mechanism in a view where you can see all three "claws", as well as the bones and the mesh. The three circles are being used for controllers. Controllers are useful because you need to be able to grab a particular bone or IK at any time and if the bones are all inside of meshes, this be tough! A big circle is much easier to spot and grab. The top (green) circle controls the height of the entire strut, the middle (pink) circle controls the elevation of the lower portion of the strut, and the lower (purple) circle controls the elevation of the claws tips.

Get the Hierarchy right

Here is the anatomy of the strut - The main bone linkages are Body, Leg, and three Claws, with a Palm bone that is a parent to all of the claws. The Palm bone is the only bone that has no other attached bones (yet). All of your bones should be positioned well before you start adding IK Solvers or parent-child relationships. The figure above shows all bones created and in-position for the first step. Note that we have colored all of the bone chains differently for clarity. The body bone chain is light green, the leg bone chain is purple, the palm bone is orange, and the claw bone is yellowish. These can all be drawn in the Front view.

Copy and rotate the claws

We only created one claw bone chain, but we actually need three. The tricky thing is that two of the claw linkages are at unusual angles to the body of the mechanism. If you study the figures above and above, you will see that the claw linkage on the right is not rotated, but the two on the left are rotated, each 45 degrees out. This was done by copying the first linkage and rotating it 135 degrees, and then copying and rotating that bone linkage another 90 degrees. If confused, see the video on the tutorials page because this rotation process may be in there. The figure above shows the entire claw bone chain being selected and copied to a new location. Note here that we are using an actual "copy", not an instance or a reference.

Rotate and Move the Claws into Position

In the figure above, the bone chain that was just copied has been rotated 135 degrees. Then it was selected and copied to a new location, and this new copy is being rotated another 90 degrees. You will end up with three claw bone chains that just need to be positioned properly before moving on.

The Hierarchy

There is the anatomy of the bone lander mechanism. The set on the left is shown with the mesh transparent, and the set on the right is shown without the mesh, so you can get an idea of how it looks in both situations. The bones are all labled as such, there are two IKs, and three control objects (these are circles as seen from the front viewport so they look like lines).

Make Parent-Child relationships and add IK Solvers

Go ahead and make a parent-child relationship between the ThighBone and the BodyBone (jump ahead to the figure on Parent-Child relationships). Then add the IK Solvers. Here's how to add the Hi solvers for the leg and claw bone linkages. Select the thigh bone (1a), go to Animation > IK Solvers > Hi Solver, and then click on the leg Nub (1b). Do the same thing for each of the claw linkages.

Select and Link

Okay - Now finish your Parent-child relationships. The way Select and Link works in 3ds Max, you select the Child object, then drag the mouse to the Parent object. Therefor we have used arrows to indicate the direction of your mouse, from child to parent, in each case. Note that the Palm bone is a child of the LegIK IK - this is because if we made the Palm a child of one of the leg bones, it would rotate when the leg was moved, and we don't want the lower section of the strut to rotate at all! By making the IK of the leg a parent to the Palm bone, it stays nice and level no matter what the leg is doing.

Adjust Rotational Joint Settings

There's just one problem with the setup as it is; when you move the lower section of the linkage, the claw bones are going to rotate a bit, which will rotate your mesh when you have this thing skinned. That would not look good. So you have to select each middle claw bone and change the Hierarchy > IK > Rotational Joint settings to those shown above. Also, you will probably want to parent the body bone to a circle controller, parent the Leg IK to a circle controller, and parent all three claw IKs to a single circle controller. Then, you can parent the claw IK controller to the Leg IK controller, and parent the Leg IK controller to the body bone controller. This way the entire unit moves when you move the body controller, and yet you can use the Leg controller to move the lower part of the mechanism as needed to flex and unflex the leg, and even use the claw controller independently to make the claws splay in and out as needed.

Done

That's it! If you need some clarification on something in this tutorial, check the Serenity Strut video tutorials.