Creating Face Accessories

A face accessory is a cosmetic Accessory that attaches to the head and can include items such as hair, eyebrows, glasses, and facial hair. To create a face accessory that is compatible with animatable heads, you use a similar design process as layered clothing to allow your accessory model to deform and stretch on a head when the head is posed or animated.

To create a face accessory, use a third-party modeling tool, such as Blender or Maya, to create a 3D model with the following requirements:

• The accessory model must meet Studio's mesh requirements.
• The model must be parented (Blender) or bound (Maya) to an R15 character rig.
• The model must include an inner and outer cage.

This guide covers the basic process in Blender for applying rigging and cage data to a basic reference model using the Cubie model referenced in Creating Basic Heads.

Reference Files

The following are face accessory reference files, including all example files from this guide:

Modeling

This guide uses a simple eyebrow reference as a demonstration for creating a face accessory. If rigging and caging a different model, ensure that your model meets the character specifications for Studio import.

If creating your own model, consider the following guidelines:

• Model your accessory with your character model for best results and fit.
• When possible, try to match up the edges of your model geometry with the edges/vertices of the underlying head topology. This improves the deformation of the accessory with the underlying head model.
• Some accessories, like eyebrows, can extrude or slightly intersect the character model mesh to achieve a certain cosmetic look.
• When working with an accessory with multiple pieces, such as eyebrows, combine the meshes to a single mesh once the modeling and fitting is completed.
• Face accessory meshes do not require a _Geo naming convention.

Rigging

You must rig your accessory to the character's bone structure so the accessory can bend and deform along with your character's facial poses. After rigging, you can skin your model in your modeling tool, or you can transfer skinning data from your character to the accessory at runtime by using Automatic Skinning Transfer.

Project Setup

As an example in this guide, we are using the completed basic Head model from Creating a Basic Head and a simple eyebrow model in a new Blender project.

To set up your Blender project:

1. Open a new General project in Blender.

2. Select the default shape, camera, and lights, then press Delete.

3. In the left-hand navigation of the Properties Editor, navigate to Scene Properties.

   

4. In the Units section, change the Unit Scale to 0.01 and the Length to Centimeters.

   

5. Import the character rig you intend to parent the accessory to, in this example: Cubie-Complete.fbx.

   

6. To simplify the workspace, you can delete the R15 inner and outer cage mesh objects since you will later import a full-body cage in the Caging step.

7. Import your accessory model, in this example: CubieEyebrow_Geo.fbx.

   1. If required, reposition the accessory model on the face.
   2. You can hide the armature temporarily to verify model placement.

   

Parenting Armature

Connect the mesh object to the character's armature by parenting the armature to the mesh object. To parent the armature:

1. In Object Mode, hold Shift and click the accessory model and then any of the character bones.
2. Right click and select Parent, then select With Automatic Weights.

Optional Skinning

In many cases, you can skip the skinning process for your accessory and use Roblox's automatic skinning transfer instead. You can still apply manual skinning through a modeling software and opt to use automatic skinning transfer later.

If you do not intend to apply skinning manually, continue directly to Caging.

Caging

The caging process for face accessories is similar to caging layered clothing accessories and shares the same modeling and caging requirements. After rigging, import a full-body inner and outer cage to your project, rename the cages, then stretch the vertices of the Outer Cage to cover the accessory model with minimal space.

To cage the eyebrow accessory:

1. With Blender's .fbx importer, import Cubie-Cage-Only.fbx. This includes a single full-body inner and outer cage mesh for the Cubie model.

   

2. Rename cages to begin with "CubieEyebrow" before the _InnerCage and _OuterCage affix.

3. In Edit mode, extend the outer cage to fit over the accessory with minimal space. Use various material and viewing options to easily manipulate the correct vertices on the outer cage.

If you are using automatic skinning transfer, you can ensure that automatic skinning transfer only applies to specific parts of the accessory by removing unnecessary sections of the cage. For more information, see Modifying Character Cages.

Exporting

Export your model when ready to test your accessory model in Studio or when setting up for final export. When exporting face accessories, keep in mind the following guidelines:

• Ensure that the final accessory model follows Studio's Modeling Requirements, including properly named mesh and cage objects.
• Do not export any unnecessary data, such as animation data, or light and camera objects.
• If exporting PBR textures, follow texture modeling requirements when exporting texture images from your texture software.

To export:

1. Ensure only the accessory mesh, armature object and cages meshes are exported. Delete all other objects in the workspace.

   1. You can quickly filter out Geo and Att named objects in your workspace to quickly delete them.

2. Follow Studio's Export Requirements for Blender and save the file to your preferred location. The final export of the eyebrow .fbx is available for reference.

Testing in Studio

To use your exported model into Studio as an Accessory, use the Accessory Fitting Tool to test and generate the accessory object. At this point, you can equip the accessory to a humanoid character. If you intend to transfer skinning data from your character to the accessory model at runtime, you can enable automatic skinning transfer for your accessory.