Adding bones to a Character in Maya

Low poly character, Jennifer, rigged and posed

So here’s my second character I modeled and posed in Maya. Let’s see how I rigged her up, starting with the model in a T-pose as below.

To start rigging, make sure you’re in the Animatons tab. Select the Skeleton –> Joint Tool and click to make joints for the spine, starting from the centre of mass.

Select the Joint Tool again and click on the centre of mass (CoM) joint created earlier. From there, continuously click to make the hip, knee, ankle, ball of foot, and toes. I won’t be using the toes for this character, but by making a joint for the toes and deleting it later helps to orient the ball of foot joint.

Using the same tool, click on the top spine joint then click on to make the collar bone, shoulder, elbow, etc. Again, I’m making an extra joint at the end and deleting it afterwards to align the last joint.

And do the same for the neck and head.

Now go to the side view and align the joints up for the character. It’s important to name the joints properly too, as it saves you a lot when skinning.

You can mirror joints by first selecting the top of the hierachy of joints you want to copy over, then firing Mirror Joint.

Choose the settings so it mirrors them in the right plane.

Once you have mirrored joints from the hip joint and also the collar bone joint, click on the CoM joint and fire off Orient Joint.

For joints that don’t align themselves correctly automatically, click on the Select Components button, then the question mark button, click on the joint, then click on one of its axis labels, then use the rotate gizmo that appears.

Once you delete any extra joints that you created earlier, select on the left collar bone joint and go to Modify –> Prefix Hierarchy Names. Enter “left_” as the prefix so that all left jonts will have “left_” prefixed to its name. Do the same for the left hip, right hip and right collar bone joints.

To bind the skin to the skeleton, go to Skin –> Smooth Bind [].

In the Smooth Bind options dialog, make sure that Maintain max influences and Remove unused influences are unticked.

Now, to put weights on the skin, start from one end of your character and select the vertices you want influenced by the end joint in Select Components mode. Go to Skin –> Edit Smooth Skin –> Paint Skin Weights Tool.

Find the joint that you want the vertices to be influenced by from the big list. (Here’s where renaming joints comes in handy!) Select on the Replace radio button, set the Value to 1 and hit the Flood button. Next, go to Modify –> Invert Selection so that all the other vertices are selected. Set the Value to 0 and hit the Flood button. The first pass for this joint is done, so click on the Toggle Hold Weights on Selected button.

To continue, get out of the painting weights tool and select the next set of vertices you want influenced by the next joint.

And follow the same step as before in the Paint Skin Weights Tool. You would do this for all the joints, then come back and tweak the values between each pair of joints. So for the second pass, you would unhold two adjacent joints and select vertices that you want influenced by the two joints. Then flood a fraction value to one joint, and the remaining fraction to the other joint so they add up to 1.

However, Maya’s default values actually does pretty well so you can pose your character first, then tweak the values where needed. Below shows the character posed straight after using Smooth Bind.

Most of her’s okay apart from her back and her right elbow. But tweaking her mesh around the elbow as per Ancient-Pig’s basic deformation tutorial and tweaking the joint influence values a little bit in the Paint Skin Weights Tool make her elbow look better.

The tweaked mesh at her elbow now has three edge loops on the outer side and two on the inner side. The edges along the top loops (one loop above the extra outer elbow half loop) should have 100% influence from the shoulder joint, the bottom loops 100% from the elbow joint, and the middle ones 50/50.

After fixing the weights of her elbow, back and heart heels, she looked like this.

Advertisements

One Comment Add yours

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s