¶AdnRibbonMuscle

AdnRibbonMuscle is a Maya deformer for fast, robust and easy-to-configure tissue muscle simulation for digital assets. Thanks to the combination of internal (structural) and external (attachments and slide on segment) constraints, this deformer can produce dynamics that allow the mesh to acquire the simulated characteristics of a ribbon with fibers activations to modulate the rigidity, and attachments to external objects to follow the global kinematics of the character.

The influence these constraints have on the simulated mesh can be freely modified by painting them via the AdonisFX Paint Tool or by uniformly regulating their influence via multipliers in the Attribute Editor. Besides the maps and multipliers there are many other parameters to regulate the muscle's dynamics and behaviour to a wide array of options.

¶How To Use

The AdnRibbonMuscle deformer is of great simplicity to set up and apply to a mesh within a Maya scene. The way this deformer works is by applying simulation on top a mesh emulating a ribbon muscle which follows the dynamics of attachment points set as anchors. Those attachments mark the anchor points for the muscle, prepared to act as tendons, and will introduce great part of the dynamics to the deformer.

To create an AdnRibbonMuscle deformer within a Maya scene, the following inputs must be provided:

• Attachments (A): Attachment anchors to which the simulated muscle will be attached to. Any transform node can be used (e.g. joints, locators, meshes, etc). This input is optional and unlimited.
• Muscle Geometry (M): Mesh that the AdnRibbonMuscle deformer will be applied to.

Follow this steps to create an AndRibbonMuscle deformer:

1. Select the Attachments (if any) and the Muscle Geometry in that order.
2. Press the button in the AdonisFX shelf or press Ribbon Muscle in the AdonisFX menu. If the shelf button is double-clicked or the option box in the menu is selected a window will be displayed where a custom name and initial attribute values can be set.
3. AdnRibbonMuscle is ready to simulate with default settings. Check the next section to customize their configuration.

¶Attributes

¶Solver Attributes

¶Time Attributes

¶Scale Attributes

¶Gravity

¶Advanced Settings

Stiffness Settings

Dynamic Properties

¶Debug Attributes

¶Connectable Attributes

¶Attribute Editor Template

¶Paintable Weights

In order to provide more artistic control, some key parameters of the AdnRibbonMuscle solver are exposed as paintable attributes in the deformer. The AdonisFX Paint Tool must be used to paint those parameters to ensure that the values satisfy the solver requirements.

¶Debugger

In order to better visualize deformer constraints and attributes in the Maya viewport there is the option to enable the debugger, found in the dropdown menu labeled Debug in the Attribute Editor.

To enable the debugger the Debug checkbox must be marked. To select the specific feature to visualize, choose it from the list provided in Features. The features that can be visualized with the debugger in the AdnRibbonMuscle deformer are:

• Muscle Fibers: For each vertex, a line will be drawn showing the direction of the muscle fibers.
• Attachments Constraints: For each vertex with an attachment constraint weight greater than 0.0, a line will be drawn from the mesh vertex to its respective attachment.
• Slide on Segment Constraints: For each vertex with a slide on segment weight greater than 0.0, a line will be drawn from the mesh vertex to the closest point to its respective segment.

Enabling the debugger and selecting one of these constraints will draw lines from the influenced vertices in the simulated mesh to their corresponding reference vertices.

¶Advanced

¶Attachments

Once the AdnRibbonMuscle deformer is created, it is possible to add and remove new attachments to the system.

• Add attachments:
  1. Select the transform nodes (one or more) to be assigned as attachments to the AdnRibbonMuscle.
  2. Select the mesh that has the AdnRibbonMuscle deformer applied.
  3. Press the button in the AdonisFX shelf or press Add Attachments in the AdonisFX menu from the Edit Muscle submenu.
• Remove attachments:
  1. Select one or more transform nodes that are assigned as attachments to the AdnRibbonMuscle.
  2. Select the mesh that has the AdnRibbonMuscle deformer applied.
  3. Press the button in the AdonisFX shelf or press Remove Attachments in the AdonisFX menu from the Edit Muscle submenu.
  4. Alternatively, if only the mesh with the AdnRibbonMuscle deformer is selected, when pressing the button, all attachments will get removed.

¶Slide On Segment Constraint

Additionally to all previously mentioned constraints, ribbon muscles can have an additional, optional constraint that can define a segment over which the muscle will slide.

• Add Segment:
  1. Select the transform nodes from which a segment would be created for the muscle to slide on.
  2. Select the mesh that has the AdnRibbonMuscle deformer applied.
  3. Press Add Slide On Segment Constraint in the AdonisFX menu from the Edit Muscle submenu.

• Remove Segment:
  1. Select one or more transform nodes that are assigned as segment anchors to the AdnRibbonMuscle.
  2. Select the mesh that has the AdnRibbonMuscle deformer applied.
  3. Press Remove Slide On Segment Constraint in the AdonisFX menu from the Edit Muscle submenu.
  4. Alternatively, if only the mesh with the AdnRibbonMuscle deformer is selected, when pressing Remove Slide On Segment Constraint in the AdonisFX menu, all segments will be removed.