Character elements like the shape and skeleton must first be packed into a character folder structure, which is then piped into an APEX AutoRig Builder SOP:

1. The APEX Pack Character SOP adds the input shape and rest skeleton to a packed character folder structure. The Shape Path and Skeleton Path parameters set the name of the shape and skeleton in the folder structure. Select the APEX Pack Character SOP and view the folder structure in the rig tree view (in the rig tree view, set Type to Packed Folders):

   /
   -- Base.shp
   -- Base.skel
   

2. The APEX AutoRig Builder SOP builds a rig with an FK control hierarchy as a starting point. Enter the Autorig Builder viewer state - select the APEX AutoRig Builder SOP, turn on its display flag, and click Animate on the left toolbar.

3. In the Autorig Builder viewer state, a guide for the character is shown on the left and a test rig is shown on the right. The guide is where you configure the rig - the joint positions, skeleton, settings - everything that needs to be prepared for the final rig. The test rig is built based on the guide’s configurations. You add rig components to the guide, then preview and try out the functionality on the test rig. For more information on the icons above the guide and test rig, see here.

   

4. You can change the rest positions of the character’s joints by moving them on the guide skeleton. When the guide skeleton changes, a red “Update” text above the test rig appears, indicating that the test rig needs to be updated to match the guide. Click the “Update” text to update the test rig. If Auto Update is turned on in the parameter editor, the test rig will update automatically.

Add a root control to the character:

1. The available rig components can be selected from the component catalog in the animate state HUD, Catalog tab. Drag the Root component from the component catalog onto the guide, and click or press Enter over the viewport. In the parameter editor, an entry for the root control is added to the Segments multiparm in the Build tab. To see the root control on the test rig, press H over the viewport or click the Update Rig icon in the parameter editor. If Auto Update is turned on in the parameter editor, the test rig is automatically updated with the root control:

   A few notes:

   • The order in which you add the rig components is important. If you want to parent all the character’s controls to a root control, first add the root component, then add the other components. The entries in the Segments multiparm represent the order in which the components are built.

   • To add components to the rig, drag and drop from the component catalog instead of using the Segments multiparm. The APEX AutoRig Builder SOP is designed for the drag-and-drop viewport interaction. The Segments multiparm is moreso a place to store and view the rig component data.

   • In the parameter editor, you can turn on Auto Update to automatically update the test rig when changes are made to the guide. For faster performance, you may want to turn off Auto Update while dragging and dropping components onto the guide. After adding all the components, you can turn on Auto Update to see all the added components at once.

2. After you move the test rig around, you can reset the rig by pressing N over the viewport, clicking the reset icon above the test rig, or clicking the Reset Test Rig button in the parameter editor.

3. To change the color of the root component on the guide, click the color chip for the root in the parameter editor, Build tab.

Configure the root control ¶

You can configure the settings on the guide and test rig through the two gear menus:

1. On the guide, click the menu to see the settings for configuring the root controls. The options in the menu are the ones most commonly used for the component. The full list of configuration options for the component can be accessed in the animate state parameters - select the menu and go to the Controls tab in the animate state HUD.

2. You can reposition the menu by dragging the control. To change the number and shape of the root controls, click and drag on the appropriate icons in the menu:

   Tip

   Depending on your transform handle settings, there may be a plane that appears at the transform handle of the menu that makes it difficult to select some of the settings directly below it:

   

   To turn off the plane:

   • Press P over the viewport to bring up the handle preferences.

   • Click the Open Handle Preferences button.

   • In the Preferences window, click on Handles in the left menu.

   • Turn off Dragging Between Axes Does Planar Drag.

   • Click Accept.

3. There is also a menu for the test rig. For the root control, the only available option is the visibility toggle:

Add spine functionality to the rig by dragging the Spine component onto the guide. In the parameter editor, an entry for the spine is added to the Segments multiparm in the Build tab.

To move the spine component to another part of the skeleton:

1. Click the spine’s menu on the guide.

2. Select the segments icon.

3. Click and drag the spine component to another joint.

4. Press Enter.

Pose the guide skeleton ¶

On the guide skeleton, there is an IK/FK icon you can click to choose between posing in IK or FK. In IK pose mode, there are IK controls you can select for posing:

Note

This functionality is different from the IK/FK setting in the test rig’s menu.

To reset the guide, click the reset icon above the guide or the button in the parameter editor.

Configure the spine controls ¶

The guide’s menu provides several options for configuring the spine functionality. For example, if you turn on the addstretchcontrol setting in the guide’s menu, an option appears in the test rig’s menu for controlling the stretch in the spine. See the gear menu options for the different types of interaction gadgets in the menu.

The stretch and squash sliders in the guide’s menu allow you to control the amount of stretch and squash on the spine. These options are only applicable when addstretchcontrol is turned on. See the spline rig component for more information.

Add arm and leg functionality to the rig by dragging the Arm Clavicle and Leg components onto the left side of the guide. To mirror the rig functionality, components must be put onto the left side of the skeleton. If you drag a component onto the right side, its functionality will not be mirrored.

Add functionality for the hands and feet by dragging the Hand Simple and Foot components onto the guide:

If your input skeleton has fewer fingers than the Hand component, turning on Remove Un when dragging and dropping the hand component removes the unnecessary fingers so that extra finger controls aren’t created. You can also choose not to add certain fingers by using the ⌃ Ctrl hotkey:

1. Drag and drop the Hand component onto the guide.

2. Hold ⌃ Ctrl and select the joints you don’t want to add. The selected joints will turn red. When you release ⌃ Ctrl, the joints will turn black, indicating that they are no longer mapped to the skeleton, so controls will not be created for those joints.

3. Click .

   

Settings on the hand component ¶

Below are some of the settings for the Hand component in the guide’s menu:

Piano hands

When pianohands is turned off (indicated with an FK icon), you have a simple hand functionality with FK controls on each finger joint as well as a selector control for each finger. Conversely, piano hands provides a more complex hand functionality that includes additional IK controls at the base and tip of each finger as well as a control that moves all the fingertips at once. When pianohands is turned on (indicated with an IK icon), the ikfkblend, ikfk_switch, and pinControls options are available in the test rig’s menu. Set ikfk_switch to IK to see the controls that affect the fingertips.

Flip selectors

The flipselectors toggle on the guide’s menu flips the position of the finger selector controls on the test rig. Finger selector controls select all the corresponding finger’s joints to make it easier to pose the entire finger.

Instead of using a rig component for the neck and head, you can use tags to configure the existing FK controls (created initially by the Autorig Builder) to be rotate only:

1. Select the neck and head joints on the guide.

2. Press ⇧ Shift + H over the viewport.

3. In the Add Tag pop up, enter a tag name for the neck/head group of joints. In our example, we use neck_head. If you want the tag mirrored, name the tag with the body side indicator, for example, L_testarm.

4. Press Enter. A menu is created near the neck and head joints on the guide, and an entry is added to the Build tab (in the parameter editor) with the entry’s drop-down menu set to Add Segment Tag. You can now use the guide’s menu to configure the color, shape, and size of the neck and head controls. You can also choose whether to promote the translate, rotate, and scale of the controls.

5. Only promote the rotate controls for the neck and head:

   • Turn on the promote_r toggle so that you can rotate the neck and head controls.

   • Turn off the promote_t and promote_s toggles so that translate and scale for the neck and head controls aren’t available on the test rig.

   • If you turn off promote_t, promote_r, and promote_s, the neck and head controls will not appear on the test rig.

The APEX AutoRig Builder SOP provides prebuilt rig templates (such as Mocap Biped and Biped) that you can use as a starting point for your rig. To apply a prebuilt template:

• Drag and drop the template (for example, Mocap Biped) from the component catalog onto the guide.

  or

• In the Build tab, turn on the Use Template parameter. Select a rig template from the first drop-down menu and a joint mapping from the second drop-down menu. Click Add or Update.

You can create a rig template by first building a rig using an APEX AutoRig Builder SOP. The components that appear in the parameter editor under the Build tab are the list of operations for constructing the full rig and they make up the rig script on the second output of the SOP. You can then pipe this output into the second input of another APEX AutoRig Builder SOP to use the rig script as a template for creating another character’s rig:

You can apply the template in the following ways:

• On the second APEX AutoRig Builder SOP, in the Build tab, turn on Use Template and select Input Template from the first drop-down menu. Click Add or Update. In the Autorig Builder viewer state, drag the template onto the skeleton and press Enter.

• In the Autorig Builder viewer state, drag and drop the “Input” component from the component catalog onto the guide and press Enter. The proportions, joint orientations, and joint names between the two skeletons can be completely different:

After applying the rig template to the character, the individual components of the template are listed in the Build tab. You can then configure each component.

The first component listed is the Fit Skeleton component, which contains the mapping from the template joint names to the target character joint names (see the Advanced section in the Fit Skeleton multiparm entry). Skeleton fitting takes a skeleton and fits it to a character with different proportions. It transfers all the information from one skeleton to another, including the joint names, orientations, tags, and properties.

Add joint mappings ¶

If you want the rig template to always work for a certain character, like a Mixamo character, you can store a joint mapping on the template skeleton that specifies the mapping between the template skeleton and Mixamo skeleton.

In the example below, the first APEX AutoRig Builder SOP creates the rig template, which contains the rig script and template skeleton. You can then add information on the template skeleton like the mapping, and pipe the rig script and updated template skeleton into the second APEX AutoRig Builder SOP:

1. On the first APEX AutoRig Builder SOP, build a rig with root, spine, arm, and leg components. The second output of this SOP is a character data stream that contains the rig script and template skeleton. In the rig tree view, set the drop-down menu beside the node name to Rig Template (output2) to see the contents of the second output - the rig script (.graph) and template skeleton (.skel).

2. The Unpack Folder SOP extracts the template skeleton from the character data stream:

   • Click beside Extract Pattern.

   • In the rig tree view, select the .skel file, in our example, template.skel.

   • Click Accept. The Extract Pattern parameter is populated with the name of the template skeleton.

3. The Map Points SOP creates a joint mapping from the template skeleton to the target skeleton and stores it as a mapping attribute on the template skeleton. On the Map Points SOP:

   • Set the mapping attribute name. In our example, we set Output Attribute Name to mapping_test.

   • Set Reference Type to Attribute Value.

   • Set Reference Attribute to name.

   • In the Map Points viewer state, map the joints between the template and target skeletons. See map source points to target points for steps on how to do this.

4. All the joints that were not mapped in the Map Points SOP will have an empty mapping_test attribute. In the rig template workflow, all the joints in the template skeleton must have a non-empty mapping attribute, so we use an Attribute Wrangle SOP to populate all the empty mapping_test attributes. Add the following VEX snippet to the Attribute Wrangle SOP:

   if (len(keys(d@mapping_test)) == 0)
   {
       d@mapping_test['value'] = '';
   }
   

5. The Pack Folder SOP adds the updated template skeleton with the mapping back into the character data stream. On the Pack Folder SOP, specify the name of the extracted template skeleton. In our example, we set Name to template and Type to skel.

6. Enter the Autorig Builder viewer state on the second APEX AutoRig Builder SOP.

7. Go to the Build tab and turn on Use Template.

   • The first drop-down menu beside Use Template lists the available rig templates. Select Input Template since we're using the template from the SOP’s second input.

   • The second drop-down menu lists the available mappings on the template skeleton. Select mapping_test.

   • Click Add or Update to apply the template.

   If you save the template to disk, click Reload Rig Components in the component catalog, and the saved template will appear in the first drop-down menu.

Note

You can also use an Orient Joints SOP to specify how certain groups of joints are best oriented. The Orient Joints SOP stores an attribute on the template skeleton that specifies how to orient the joints. You can put the Orient Joints SOP before or after the Map Points SOP.