Houdini 21.0 Character KineFX

Maya™ transition guide for character and animation

On this page

This page highlights some of the translations and differences between Maya™ and Houdini within the realm of character animation and rigging.

See the general Maya transition guide for some of the basic differences in the user interface concepts and hotkeys between Maya and Houdini.

Note

On the Mac, use ⌘ instead of ⌃ Ctrl.

Concepts

Function

Maya

Houdini

Choose channels to key

Channel Box

Channel list, animate state parameters HUD

Edit animation curves

Graph Editor

Graph view of the animation editor

Edit animation timing

Dope Sheet Editor

Dopesheet of the animation editor

Control animation playback

Time Slider, Range Slider, and playback controls

Playbar

Identify events in animation

Time Slider Bookmarks

Animation bookmarks

Group character controls

Character sets (groups controls), Display Layer Editor (controls visibility)

Selection sets

Create layers of animation

Animation Layer Editor

Animation layers pane

Edit animation clips

Time Editor

Motion mixer

Modify rig functionality using graphs

Node Editor

APEX network view

Preview animation

Playblast

Flipbook

Moving objects

Maya’s manipulator is Houdini’s handle. Houdini’s handle preferences can be found in Edit ▸ Preferences ▸ Handles.

In the table below, the Houdini functionality can only be performed on the handle in the animate state. For an animate state handle configuration that may be more familiar for Maya users:

  1. Go to the animate state handle preferences in Edit ▸ Preferences ▸ Handles, Defaults tab, APEX Animate Transform section.

  2. Turn on Apply APEX Handle Settings Automatically.

  3. Set Presets to Traditional and click Apply Preset.

See the general Maya transition guide for handle translations between Maya and Houdini outside of the animate state.

Function

Maya

Houdini

Move

W

T or click on the left toolbar

Rotate

E

R or click on the left toolbar

Scale

R

E or click on the left toolbar

Move an object along a particular axis

Click a transform component and drag

In Houdini’s handle preferences, Defaults tab, APEX Animate Transform section, turn on Indirect Drags Apply to Selected Component. You can now select a transform component and drag as is done in Maya.

Change the manipulator alignment

Hold W/E/R (for translate/rotate/scale), hold down the , and select World or Object

click the viewport, and select one of the options in Alignment.

Change the manipulator size

+, -

* (larger), & (smaller)

In Houdini’s handle preferences, Defaults tab, APEX Animate Transform section, adjust the Global Scale.

Setting keys

Function

Maya

Houdini

Set a keyframe

S

Keyed attributes are indicated in red in the channel box, time slider, and attribute editor.

K

Keyed channels are indicated in green in the channel list, timeline, and parameter editor. See how keyframes are color coded.

Key translate

⇧ Shift + W

⇧ Shift + T

Key rotate

⇧ Shift + E

⇧ Shift + R

Key scale

⇧ Shift + R

⇧ Shift + E

Turn on auto-key

Auto keyframe toggle

On the playbar keyframing controls, click the arrow beside the keyframe button and turn on/off Auto-key changes. See auto-keying for more information.

Note

Maya users may want to turn off the auto-commit option.

Editing channel values

Maya’s channel box is Houdini’s channel list.

Function

Maya

Houdini

Adjust channel values

In the channel box, drag the attribute values.

In the channel list, drag the channel values, which brings up the value ladder.

Editing animation curves in the graph editor

Maya’s graph editor is Houdini’s animation editor graph view. The image below shows the different handles in Houdini’s graph view:

In Houdini, animation curves are often referred to as animation channels. Tangents are controlled by the slope handle, and tangent lengths are controlled by the acceleration handle.

Function

Maya

Houdini

Scrub within the graph editor

Hold K while dragging.

Drag the time bar that indicates the current frame.

Framing options

The view option buttons on the top toolbar:

  • Frames all the displayed keys.

  • Frames the playback range.

  • Centers the view at the current time.

On the right toolbar:

  • Home Channels displays all the graph data.

  • Vertical Adapt displays all the graph data vertically.

  • Horizontal Adapt displays all the graph data horizontally.

To frame part of the graph data:

  1. drag to select part of the graph.

  2. Click Frame Selection.

See navigating in the graph view for more information.

Scale the graph editor view

Alt + ⇧ Shift + drag

drag

Set the curve display options

Absolute View - press 1

Stacked View - press 2

Normalized View - press 3

  1. Select Toggle Normalized Values Display Mode on the right toolbar.

  2. click and select one of:

    • Parameter UI Range - same as Absolute View in Maya.

    • Animation Range - same as Normalized View in Maya.

    • Animation Range with Offset - same as Stacked View in Maya.

See the graph view display toolbar for more information.

Go to the previous/next keyframe

, to go to the previous keyframe.

. to go to the next keyframe.

Same as Maya or ⇧ Shift + ← to go to the previous keyframe.

Same as Maya or ⇧ Shift + → to go to the next keyframe.

Move the selected keyframe in any direction

Drag the keyframe.

or

Select the keyframe and drag anywhere in the graph editor.

⌃ Ctrl drag the keyframe.

or

Select the keyframe and ⌃ Ctrl + drag anywhere in the graph view. (Make sure Show Value Handles on the right toolbar is turn on.)

Move the selected keyframe in X or Y only

⇧ Shift drag the keyframe.

or

Select the keyframe and ⇧ Shift + drag anywhere in the graph editor.

Drag the keyframe. The direction is locked to the initial drag direction.

or

Select the keyframe and drag anywhere in the graph view. (Make sure Show Value Handles on the right toolbar is turn on.)

Move the selected keyframe forward or backward a specific number of frames

In the time field:

  • Type +=10 to move the key forward 10 frames.

  • Type -=10 to move the key backward 10 frames.

In the Frame field:

  • Type +10 to move the key forward 10 frames.

  • Type +-10 to move the key backward 10 frames.

Scale a group of keys

Enter the scale tool (press R), select a group of keys, and drag.

Click Box Handle on the top toolbar, box select a group of keys, and drag a corner of the box.

Change the shape of the curve

Choose from the options on the top toolbar or the Tangents menu.

Choose from Constant Function (step tangents in Maya) or Linear Function on the top toolbar.

or

Select from the Function field on the bottom toolbar.

or

Use the Curve Pulling tool on the top toolbar.

Weighted and non-weighted tangents

Select Curves ▸ Weighted/Non-weighted Tangents, or a curve and select Weighted/Non-weighted Tangents.

By default, channels in Houdini are Bezier curves, where the slope and acceleration can be changed (weighted tangents in Maya). If you want non-weighted tangents, change the channel to a cubic curve:

  • Select the curve, click the graph view, and select Set Selected Segments to ▸ Cubic.

    or

  • Select the curve and set the Function field on the bottom toolbar to cubic().

You can change the default curve in the animation preferences, which can be accessed through Houdini’s Edit menu ▸ Preferences ▸ Animation. In the Initial Segment section, set the Default Function and Rotation Function.

Lock the tangent direction

⇧ Shift + drag the tangent handle.

⌃ Ctrl drag the acceleration handle.

Change the tangent to a flat tangent

Select a key and click the Flat tangents button.

  1. Select a keyframe.

  2. Press 0.

    or

    click the graph view and select Set Selected Slopes to Zero.

See the graph view for more ways to set the slope values with the Set Selected Slopes to* options.

Separate or unify the left and right sides of the tangent handle

Click the Break tangents and Unify tangents buttons.

Click the Untie Values and Tie Values buttons.

Cycle the animation

Click the Pre-infinity cycle and Post-infinity cycle buttons.

Select Channels ▸ Edit Channel Properties. In the window that pops up, set the behavior of the curve under the Before and After columns, for example, Cycle and CycleOffset. See the Edit Channel Properties window for more information.

Working in the timeline

Maya’s time slider, range slider, and playback controls are encompassed in Houdini’s playbar:

Playing back animation

Function

Maya

Houdini

Play animation

Alt + V

↑

Play animation in real time

click the time slider and select Playback Speed ▸ Real-time.

Turn on the Real Time Toggle on the playbar.

Loop the animation

Click the loop button on the time slider to cycle through the different playback options.

On the timeline, click the button for the different playback options.

Next frame

Alt + .

Same as Maya or →

Previous frame

Alt + ,

Same as Maya or ←

Next keyframe

.

Same as Maya, ⇧ Shift + →, or

Previous keyframe

,

Same as Maya, ⇧ Shift + ←, or

Display the frame rate

Turn on Display ▸ Heads Up Display ▸ Frame Rate

Press D over the viewport to bring up the Display Options window. In the Guides tab, turn on Draw Time (FPS).

Animation preferences

The Animation and Time Slider sections in the Preferences window - Windows ▸ Settings/Preferences ▸ Preferences.

The animation preferences can be found in Edit ▸ Preferences ▸ Animation.

To open the animation playback settings, click the Global Animation Options button on the playbar.

Editing keys

Function

Maya

Houdini

Move a key

  1. ⇧ Shift click a key.

  2. Drag to move the key.

drag a key in the timeline.

Move a range of keys

  1. ⇧ Shift drag on the time slider to select a range of keys.

  2. drag to move the keys.

Same as Maya.

Copy a key

  1. ⇧ Shift click a key.

  2. ⌃ Ctrl drag to copy the key.

  1. Go to a frame with a key.

  2. ⌃ Ctrl + C over the timeline to copy the key.

  3. Go to another frame.

  4. ⌃ Ctrl + V over the timeline to paste the key.

Copy a range of keys

  1. ⇧ Shift drag on the time slider to select a range of keys.

  2. ⌃ Ctrl + drag to copy the keys.

  1. ⇧ Shift drag on the timeline to select a range of keys.

  2. ⌃ Ctrl + C over the timeline to copy the keys.

  3. Go to the frame you want to copy the keys to.

  4. ⌃ Ctrl + V over the timeline to paste the keys.

See editing keys on the timeline for more copy and paste options.

Scale a range of keys

  1. ⇧ Shift drag on the time slider to select a range of keys.

  2. Drag the arrow at the end of the range selection.

  1. ⇧ Shift drag on the timeline to select a range of keys.

  2. ⇧ Shift + drag the end of the range selection.

Animating

The animation functionality in the table below can only be performed in Houdini’s animate state.

Function

Maya

Houdini

Add a constraint

  1. Select the parent.

  2. Hold ⇧ Shift and select the child.

  3. In the Animation or Rigging menu set, select Constrain ▸ Parent.

  1. Select the child.

  2. Hold ⇧ Shift and select the parent.

  3. Press H.

Adjust the parent’s influence on the child

  1. Select the child.

  2. Press S.

  3. Adjust the Blend Parent attribute.

  1. Select the child.

  2. Press G over the viewport to bring up the parameters HUD.

  3. In the Constraint tab, adjust the Blend parameter.

Create an aim constraint

Select Constraint ▸ Aim.

Create a LookAt constraint.

Create a locator

Select Create ▸ Locator.

  1. Click Locator on the toolbar directly above the viewport, or select Locator from the radial menu (press C over the viewport).

  2. Press H.

See locators for more information.

Create breakdown poses

Use tweenMachine.

The animation toolbar consists of simple slider tools that allow you to quickly create breakdown poses and apply modifications to animation curves.

Displaying controls and geometry

Maya’s character sets are Houdini’s selection sets. Houdini’s selection sets allow you to group controls and manage their selection and visibility. The visibility of character geometry can also be controlled using selection sets.

Selection sets can only be used in the animate state.

Function

Maya

Houdini

Create a set

  1. Select the controls you want to add to a character set.

  2. In the Rigging menu set, select Control ▸ Create Character Set.

  1. Select the controls you want to add to a selection set.

  2. In the selection sets pane, click the Create Set from Current Selection button on the top menu bar.

Show/Hide controls

Alt + 1

In the selection set pane or HUD, toggle the / button.

Show/Hide the geometry/character

Alt + 2

In the selection set or HUD, toggle the / button.

Hide objects during playback

In the display layer editor, turn off P for the set.

In the animate state’s handle parameters window, there are options to Hide Controls During Playback, Hide Controls During Scrub, and Hide Controls During Drag.

Skeletons

In Houdini, a joint is just a point with a name attribute, so you can use any method to create a set of points, and connect the points to a Skeleton SOP or Rig Doctor SOP to turn the points into joints. See working with skeletons for more information on how to create a skeleton, orient and mirror its joints, and blend between different skeletons.

Function

Maya

Houdini

Create joints

In the Rigging menu set, select Skeleton ▸ Create Joints.

To create joints at the center of a mesh, turn on Projected Centering.

The outliner displays the joint hierarchy.

Use the Skeleton SOP. See creating skeletons for more information.

To create joints at the center of a mesh, set Joint Placement to View Based in the Skeleton viewer state. To enter the Skeleton viewer state:

  1. Select the Skeleton SOP.

  2. Click on the left toolbar, or hover over the viewport and press Enter.

The rig tree view displays the joint hierarchy.

Tweak the joints

Select a joint, select the move tool, and on the move tool settings, turn on Preserve Children and Tweak Mode. Alternatively, enter pivot mode by pressing Insert.

In the Skeleton viewer state, set Mode to Modify, and turn on Child Compensate and Tweak Mode. See the Skeleton SOP for more ways of selecting and manipulating the joint hierarchy.

Parent joints

Select the child joint, ⇧ Shift select the parent joint, and press P.

In the Skeleton viewer state, set Mode to Create. Click the parent joint, then click the child joint.

Orient joints

In the Rigging menu set, select Skeleton ▸ Orient Joint.

See orienting joints.

Mirror joints

In the Rigging menu set, select Skeleton ▸ Mirror Joints.

Use the Skeleton Mirror SOP. See mirroring skeletons for more information.

Skinning

Maya’s “bind skin” is Houdini’s capture method, which creates weights on geometry for skin deformation. Houdini provides different methods of creating weights on geometry through the use of several SOPs, including the Joint Capture Biharmonic SOP, Joint Capture Proximity SOP, and Capture Packed Geometry SOP. See skin capture for more information on how to use these SOPs.

Function

Maya

Houdini

Skin joints

Select Skin ▸ Bind Skin.

See skin capture for information on how to use the different capture SOPs to create weights on geometry.

Paint skin weights

Select Skin ▸ Paint Skin Weights

Use the Joint Capture Paint SOP. See paint capture weights for more information.

Rigging

Houdini’s pre-built rig components allow you to easily add functionality to your character rig. For example, Houdini’s multi IK rig component adds IK functionality similar to creating an IK handle in Maya.

See the rigging overview for other methods of building rigs in Houdini.

Function

Maya

Houdini

Create a control for a joint

Create a curve for the control, parent the control, constrain the control to the joint.

The FK transform rig component takes your entire skeleton and transforms it into a rig hierarchy, where each skeleton joint is represented as a node in the rig. You can then easily turn any rig node into a control. See rigging a simple geometry for an example.

Hide certain control transform components/attributes

an attribute and select Lock and Hide Selected.

On the FK transform rig component, only specify the control transform components you want access to in the Promote T, Promote R, and/or Promote S parameters.

Change the color of a control

In the attribute editor, change the color of the control in the Display ▸ Drawing Overrides section.

Use the APEX Configure Controls SOP to configure the look and behavior of controls, including their shape, color, visibility, and transform limits. See rigging a character for an example use of this SOP.

Add IK functionality

In the Rigging menu set, select Skeleton ▸ Create IK Handle.

Use the multi IK rig component. See rigging a simple geometry and rigging a character for example uses of this component.

Add IK spline functionality

In the Rigging menu set, select Skeleton ▸ Create IK Spline Handle.

Use the spline rig component. See rigging a character for an example use of this component.

Create a basic rig

In the Rigging menu set, select Skeleton ▸ Quick Rig.

Use the APEX Autorig Builder SOP.

KineFX

Overview

Preparing character elements

Rigging with APEX graphs

Building rig graphs with APEX Script

Rigging with rig components

Animating in the viewport

SOP-based animation

Deformation

Animation retargeting

Pre-H20

Panes

Appendix