Post 06 - 3ds Max: The Biped

One method of creating a rig is the Biped rig. This is a pre-fabricated rig, inside of 3ds Max. Additional digits such as the number of fingers, toes and 'knuckle joints' can be added. The user would then scale and fit the rig into the appropriate model. Other basic options include the ability to plan out a walk or run cycle using 'foot prints', which the rig would then follow.

I applied the biped to the ZBrush model. This was scaled to fit inside the model and then attached (or 'skinned') using the 'physiques' modifier. The main method for attaching a rig is known as 'skinning' and usually is done so using the 'skinning' modifier (in other words, the physique modifier is used less and isn't as well known). Once applied, each limb and joint has what are known as 'envelopes', which are pockets that surround the limbs and determine the amount of influence the corresponding limb or joint as over the model (skin to bone). These then had to be tweaked and manipulated in a variety of ways in order to get the desired result (such as parent and child blending, plus positioning and scaling of the envelopes).

When using the biped rig, it is very easy to have an unwanted skin deformation, which looks messy and is certainly not of an industrial quality. 'Fall off' and editing of the vertices' weight would usually reduce this issue, but it was very difficult to irradiate this completely when working on a biped rig (this can be seen mostly on the hip joint connecting the legs). The resulting rig is the first rig I have successfully made and applied to a model. The following is a list of what is controllable for position and rotation:

Head, neck, all fingers and thumbs, hand/wrist, lower arms, upper arms, clavicle, chest, spine (four joints), hip, thighs, lower legs, ankle, heal and toes (toes all move together).

This rig however has only a small amount of IK (inverse kinematic) components; so as a result of this can be awkward to animate. For example, when rotating part of the spine, some parts of the rig are affected by this and other parts are not so much. In addition, there are no controls assigned to the rig, so manipulating the rig is done by freezing the model, so that selecting parts of the biped would allow control over it (although controls are something that I will be covering in due course).

This is a very basic rig and has very little in the way of features. However, as this is my first rig, I am happy with the outcome as it has allowed me to demonstrate one method of rigging. This rig would be most suitable for a very basic/simple biped character, which didn't really need a lot of time spent making every aspect of it perfect. Examples of this could be audience or spectator characters in a racing / tennis game where the attention is not on them, but on the main happenings of the game. The biped rig has been included with 3ds Max for a considerable amount of time, so it can be said (as mentioned earlier) that it is quite dated and isn't particularly used in the animation or games industries. However, in reference to the difficultly and production time, it was very quick to create and size up. The envelopes and skinning took a little longer but overall it took a matter of a couple of days, so this was beneficial and would suit a situation that required a quick mock up or visualisation.

As a result of making this biped rig, I have learnt how to make, scale and skin in 3ds Max on a basic level. I have also been introduced to some useful tools such as the ability to copy joint positioning coordinates and mirror them onto the other side (left leg to right leg, etc). In addition, I have also began to understand the importance of envelopes, as well and vertex weighting and how to manipulate them. The video below shows the skinned rig, although it is quite clunky and is very basic. It also demonstrates problem ears such as the back of the legs, the pelvis-leg join and the arm joints.

Biped Rig / Skin clip - LINK

The next stage is to look into custom bone systems in 3ds Max using the DVD: The Intermediate Rigging Kit by Paul Neale. as reference.

Here were a couple of web links I used to get started with rigging (namely, biped rigging).

3ds Max Rigging Tutorial - LINK
Second 3ds Max Tutorial - LINK