KAT UT2003 Tutorial

< KAT UT2003 Tutorial

Creating a UT2003 Ragdoll: A Brief KAT Tutorial (Page 4)

Step 8: Change the joint types

When you simulated the asset in the last step, you will have noticed that all the joints were free to rotate, but not violate their positions relative to the parts that they joined. This is because they are Ball and Socket joints. These are not very useful for ragdolls, but because they have no parameters to tune, are set as the default by the importer. To see a joint's type, press the Properties button in the joint list. At this point, if you select all joints (use the flyout in the joint list -- that's the button with a triangle on it), you will see in the joint properties dialog that all the joints are Ball and Socket.

We are going to use a mixture of Skeletal and Hinge joints in this skeleton. Most will be skeletal so, with all joints selected, change the Type drop-down to Skeletal.

Joint List

Step 9: Skeletal Joints

To properly edit joints, you should use a Joint Editing view mode (number 4 is best). Now when you select a joint (blue blob), any joint limit associated with that joint is displayed. If you still have all joints selected, you will see quite a confusing display, so click away from the ragdoll in the viewport, and then select a single joint. Let's first look at the right upper arm, which makes the shoulder articulation. The skeletal joint constrains motion of parts to an elliptic cone. The initial orientation of the child part is represented by the X (primary) axis of the joint, which can rotate within the blue cone which is held in the parent's reference frame. To change the range of motion allowed by the joint, just drag the red handles on the edge of the cone. Shift-drag will move both at once. You may find selection lock (spacebar) useful if you miss the handles.
After you have adjusted the shoulder joint so that it allows a large range of vertical motion, but not much front-to-back movement, you might want to copy it to the left shoulder. To do this, leave the source joint selected, and right-click on the destination. A context menu will give you the option of copying the joint parameters. After you have set the Upper Arm joints, set the Thigh joints (hips) in a similar manner, this time allowing plenty of front-to-back movement, but not much sideways freedom. You may like to play with the Twist options in the Joint Properties dialog. Note that KAT 1.3 users will see a much more complex skeletal joint. If you are authoring for UT2k3, be aware that many options will be discarded as you save into the 1.2 ka format.
The rest of the joints except the elbows and knees should now be made into tightly-limited cones, so that some flexibility is allowed, but not too much. The easiest way to do this is to carefully select all the joints, and bring up the Joint Properties dialog. From here, enter values of around 0.1 to 0.3 for the X and Y Cone Half Angles. You may then want to simulate to see the effects. Note that it is possible to 'pin' parts to the world when you simulate. Enter a view mode that lets you select parts (the default, 1, will do), and right-click a part. Select the Pin Part option. To unpin, just select Unpin All Parts from the context menu. You will probably find that you want to open up the 'Spine' joint slightly, and make the 'Neck' joint such that only a little sideways motion is allowed. The neck might also be modelled as a Hinge... [Remember to Save your work]