ACS2 manual covers new features as well as existing functionality that was changed or updated in ACS2 release. For any features not covered in ACS2 manual, please refer to ACS1 manual.
ACS2 is installed from a .lpk file that is a custom format for MODO kits installations. The installation is drag and drop based, the .lpk file needs to be simply dropped into MODO viewport and the installation process will be performed automatically. In case of any issues, the .lpk extension can be changed to .zip and all contents unpacked then copied to MODO’s Content/Kits folder manually.
Riging a character with ACS2 can be very fast. The minimum number of steps is as follows:
1. Drop biped rig preset into scene.
2. Set character name.
3. Assign bind mesh to the rig,
4. Set character proportions using guide mode (or drop a guide preset).
5. Bind the mesh to the rig.
6. Attach eyes as rigid meshes.
ACS2 adds following components inside MODO:
1. ACS entry in the main menu that contains all ACS tools and access to the Settings panel.
2. ACS Main and Animate palettes.
3. ACS Main Toolbar is added to the Setup Layout as an extra tab. The toolbar is the equivalent of the Main palette.
4. ACS presets path is added to Assemblies browser in Setup layout.
All ACS presets are accessible using the Presets button present both in the main ACS toolbar as well as from the ACS menu.
ACS2 will automatically update any ACS1 characters for maximum compatibility with new version the first time you’ll try to use ACS2 with an ACS1 character. The auto update is only applying safe changes that make ACS1 character work better with ACS2 and do not involve changing the rig structure. As a result of this the auto update does not bring all the new rig features into the ACS1 rig.
ACS2 includes a set of sample files that can be used for learning rigging and animation tools that ACS2 offers.
Animate palette provides all the tools required during animation process arranged in a simple and efficient way. Most of the tools are common with ACS main palette. However, there are a few that are unique to animate palette only.
ACS2 comes with 7 pie menus that can be used to speed up the workflow. Pie menus contain most commonly used tools as well as a few tools that are available via pie menus only. Pie menus have to be mapped to keys before they can be used. Pie menus include:
1. Character Contexts Pie
2. Segmentation Pie
3. Joint Influences Pie
4. Weighting Tools Pie
5. Animation Pie
6. Fit Viewport Pie
7. Controller Sets Pie
A number of smaller updates to the biped rig were added in ACS2 such as:
1. Neck aim control merged into head control.
2. Metacarpal controls linking.
3. New foot twist control for banking the foot without lifting foot toes.
4. Roll guides are hidden by default in edit guide mode.
Detailed overview of the new squash & stretch and offset controls. New controls are available for legs, arms, torso and neck. Stretch controls include option for keeping volume while stretching. IK chains can be stretched automatically when a goal control cannot be reached. Also, stretching limbs can be controlled separately for arm/foream and upper leg/lower leg.
Poses and Actions
Poses and Actions
Poses and actions library allows for reusing animation data between scenes or even characters and works within MODO’s native presets system. Poses and actions can be dropped into scenes just like any other presets and are presented with thumbnails. Every character stores its own poses and actions folder which means that whenever you want to save or load an action or pose the preset browser will open set to the correct folder for the particular character. Such workflow minimises the need to switch between various locations in the library.
Loading a pose drops it at origin of character space by default. However, you can easily drop a pose so it matches the current position of the character in space. This is done by selecting one of available reference points before loading a pose. A reference point can be one of following rig controls: an IK heel control, IK hand control or a root control. This makes it very easy to build a continuous motion in which each subsequent pose matches the position of the previous one.
ACS drop server offers additional options to dropping poses, depending on the type of the pose you want to drop. Entire character pose or a pose that contains controls on both sides of the character can be mirrored on drop. Presets that contain controls for only one side of the character (such as hands) can be dropped on either side of the character.
A pose can be saved either for entire character or for any part of it. When no controls are selected a pose is saved for entire character. When a subset of controls is selected only these controls will be saved inside the preset. ACS recognises when you save controls from one side of the character only and hand poses are a special case recognised as well.
There are 2 variations of the pose save command to give you a choice between saving pose with either default thumbnail or a manually chosen one. Saving with own thumbnail opens a new viewport in which you can choose framing for the thumbnail that will be captured from this viewport.
Action can be loaded in a few different ways with a mirror option for each. It can be loaded as a new action, it can replace current action and it can be merged into the current action. When merging, the loaded action will be pasted at the current frame on top of any animation that is already there. Reference controls are supported in merge mode in the exactly same way as in case of loading poses.
An action is always saved for the entire actor. Optionally, you can choose whether to include master control in the action preset or not. This is set via the ACS settings panel available from main ACS menu.
Just like in case of pose presets, an action preset can be saved either with a default thumbnail or a manually chosen one. Saving with own thumbnail opens a new viewport in which you can choose framing for the thumbnail that will be captured from this viewport.
There are 3 mirroring modes for poses: standard (flips both sides), push (mirrors to the other side) and pull (mirror from the other side). Mirroring poses also supports reference controls such as IK foot heel controls, IK hand controls and hips. When these controls are selected mirroring happens around these controls rather in character space. Mirroring actions works in standard mode only and happens always in the character space.
ACS2 provides a streamlined workflow for retargeting motions from .bvh files onto ACS character rig that involves just a few clicks to complete. Native MODO retargeting tool is utilised in the process. The sequence of commands is:
1. Select bvh skeleton root joint.
2. Hit Retarget Init button to put the rig into a state in which it’s ready for retargeting.
3. Enable Retargeting Tool.
4. Use Auto Add Retargeting Links button to automatically link equivalent joints in bvh and ACS retarget skeletons.
5. Bake the retargeted motion onto ACS character.
Correct character rest pose is crucial to avoid retargeting errors (such as twisted arms). T-Pose is the most optimal but MODO can compensate for arms lowered down to about 45 degrees (A-Pose). Any lower then that will most likely cause retargeting errors. An illustration below outlines acceptable and non-acceptable rest poses.
Retargeting support is implemented through a special Retarget Skeleton which sits ‘underneath’ the regular control rig. This makes it possible to animate over retargeted motion. New Retarget context is used to access the skeleton and the skeleton can also be visible in the Animate context. A dedicated retarget skeleton panel allows for fading parts of the retargeted motion in/out as well fading in/out the entire skeleton at once.
ACS2 allows for animating over the retargeted motion using all the standard rig controls. Animation created with FK controls is added on top of the retargeted motion while IK animation overrides the retargeted one. It’s also possible to blend between retargeted and hand animated motions. This is done by using retargeting panel in which the entire retarget skeleton can be faded out.
IK/FK matching allows for seamless switching between IK/FK animation on arms and legs. Matching is drag and drop based and is performed when any IK limb control is dropped onto any FK control from the same limb (or vice versa of FK/IK matching).
Selection tools make it easy to work with various parts of the rig. You can select following groups of controls: posing controls, all controls, item controls, channel controls, controls keyframed at current time and translate controls. MODO’s item selection sets are supported too. ACS rig comes with a group of predefined sets but custom ones can be added using native MODO functionality. There are also separate buttons for quickly selecting right and left hand controls.
Selection tools can add (using shift) or remove (using ctrl) from selection making it very easy to combine all the selection tools together to make an exact controls selection that you need.
Keyframe editing tools make it easy to work with animation data. The tools can work in 3 different modes: on selected controls, on selected channels or on entire character. A Force Character Mode button can be used to turn the entire character mode permanently.
Keyframe editing tools include:
2. Reset - resets control/channel selection or an entire pose.
3. Remove Animation – removes animation but keeps channels/controls values at current time.
4. Clear Animation – removes animation entirely, reseting channels/controls or entire pose to the rest pose.
5. Keyframe statistics – show keyframes and envelopes count.
6. Filter Static Keys – removes keyframes that do not contribute to the envelope flow.
7. Filter Static Keys and Envelopes – same as above but will also remove all the envelopes that do not change in time.
A few simple tools streamline the workflow for creating animation previews from open GL captures. A settings panel allows for configuring the viewport from which preview will be recorded. Preview filename is stored with the scene so there is no need to pick the file everytime the preview is recorded.
Bind Mesh Proxies
Bind Mesh Proxies
Overview of the bind mesh proxy mode in which a deformed bind mesh can be replaced with a set of meshes attached to bind skeleton joints. Bind mesh proxy mode can be used to achieve better playback performance while still having good approximation of character’s poses during animation process.
Bind mesh proxies support selection redirecting which means that bind mesh proxy mode can be used to manipulate the rig without having any of the locator controls visible. A single bind mesh proxy can redirect to up 2 rig controls (one IK and one FK).
Adobe Fuse (Mixamo) support allows for easier rigging of characters exported from Fuse Auto Rigger. While in edit guide mode drag the root guide onto the root joint of the Fuse character skeleton to apply Fuse skeleton proportions to ACS guide. Upon binding the character ACS will also recognise Fuse weight maps and will ask you whether to use these instead of the default bind.
Baking is a process of simplifying the ACS rig to a single hierarchy of joints that can then be exported to external applications such as Unity or Unreal Engine. Baking multiple actions is now supported. By default, baking will also save a copy of the scene with a postfix so the original file is not affected. This behaviour can be configured via the ACS settings panel.
Baking supports applying custom naming schemes to the baked skeleton. Custom names can be set using Label channel in skeleton joint’s Display properties. During baking process skeleton joints names are changed to these from labels. Naming scheme for entire skeleton can be saved out as a preset for subsequent reuse.
Snapshot freezes character’s current pose into a separate mesh. Use this feature to generate new meshes out of animated poses.
It’s possible to remove all ACS rig’s representation from schematic view which allows for making the scene size much smaller. Use this tool to optimise scene file size when all the setup work on the character is done.
ACS1 manual covers all the features not mentioned in ACS2 one. Although UI has been expanded in ACS2, the videos in ACS1 manual should still be easy to follow. ACS1 manual can be downloaded and installed as a kit. Follow installation instructions below.