ShapeSync

Chapter 2: Initial VRM Data Generation

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This chapter explains the steps to prepare base models (Base VRM and FBM VRM) using VRoid Studio for character body shape deformation tracking in ShapeSync.

[!NOTE] All tasks in this chapter are performed within VRoid Studio. Registering models in ShapeSync Editor and Unity will be covered in subsequent chapters (Chapter 3 onwards).

1. Introduction (Glossary for Beginners)

Before starting the tasks, here is a simple explanation of terms used in this chapter.

2. Reasons for Creating Two Models: Base and FBM

ShapeSync calculates body shape deformation by comparing the meshes of the standard body model (Base) and the deformed body model (FBM), computing the amount of shape change from the vertex position deltas.

Therefore, the following strict conditions are required for both Base and FBM models:

  1. Identical Topology: The vertex count and mesh structure of the base body must match completely between Base and FBM.
  2. Remove All Hair, Outfits, and Accessories: If hair, clothing, or accessories remain, the vertex count and mesh structure will differ between models, breaking the identical topology.
  3. Do Not Reduce Polygons: Using polygon reduction features during VRM export alters the vertex structure. Therefore, all reduction settings must be consistently turned OFF.

[!WARNING] If Identical Topology is Broken If the vertex counts between Base and FBM do not match, an error will occur in subsequent steps (when importing into ShapeSync) and the process will fail. Since it is difficult to identify “which accessory caused the issue” from the error message alone, it is extremely critical to align the composition of both models before exporting the VRM files.

3. Creating the Base Model in VRoid Studio

First, create the standard body shape model (BasicFemale) that serves as the baseline, and export it as VRM 1.0.

Step 1: Creating a New Model and Selecting Female Model

  1. Launch VRoid Studio and click Create New (+ icon) on the home screen.
  2. When the “Select base” screen appears, select Female.

Select Create New ▲Figure 2-1: Selecting “Create New” on the VRoid Studio home screen

Select Female model ▲Figure 2-2: Selecting “Female” in base selection

Step 2: Removing All Hair, Outfits, and Accessories

The newly created model is equipped with default hair, clothing, shoes, etc. To create a base body with identical topology, remove all of these items.

Default state (wearing hair and clothes) ▲Figure 2-3: Initial state immediately after creation (default outfit and hair applied)

  1. Open the Hairstyles tab and unequip all applied hairstyle items (set them to unselected/unapplied).
  2. Open the Outfits tab and unequip all outfit items such as tops, bottoms, shoes, and socks, leaving only the base body (inner underwear).
  3. Open the Accessories tab and confirm that no accessories are equipped.

State with all hair, outfits, and accessories removed ▲Figure 2-4: State after removing all hair, outfits, and accessories, leaving only the base body

  1. From the top-left menu, save the file as BasicFemale.vroid.

Step 3: VRM Export Settings and Value Verification

Export the base body in VRM 1.0 format.

  1. Click the export icon in the upper right corner and select Export VRM from the menu.

Select Export VRM ▲Figure 2-5: Selecting “Export VRM” from the top-right menu

  1. In the settings panel on the right, open Reduce Polygons.
  2. Turn OFF (uncheck) both Edit Hair Cross-Section and Delete Transparent Meshes.
  3. Confirm that all reduction adjustment sliders (Hair smoothness, Hair, Face, Body, Outfits) are set to 0.
  4. Check the Polygon count, Material count, and Bone count displayed in the Export Info at the top right of the screen, and take note of them.

Turn OFF polygon reduction options and check values ▲Figure 2-6: Turn OFF all polygon reduction options and verify Export Info (Example measured values: Polygons: 19214 / Materials: 9 / Bones: 59)

[!IMPORTANT] Regarding Export Info Values Standard measured values in VRoid Studio 2.14.0 are “Polygons: 19214 / Materials: 9 / Bones: 59”, but numbers may vary depending on the VRoid Studio version. What is essentially important is that the values on the FBM model side created next match the values on the Base model side completely.

Step 4: Exporting VRM 1.0

  1. Click the Export button in the lower right.
  2. In the “VRM Settings” dialog, configure the following:
    • Export Format: Make sure to select VRM1.0 (*Do not select VRM0.0).
    • Avatar Name (Required): Enter BasicFemale.
    • Creators (Required): Enter an author name (your name or handle).
  3. Execute export at the bottom and save the file as BasicFemale.vrm.

VRM 1.0 export settings (BasicFemale) ▲Figure 2-7: Selecting VRM1.0 format and setting avatar name to BasicFemale

4. Creating the FBM Model in VRoid Studio

Next, create the FBM model (SampleI) that serves as the reference for body shape deformation.

Step 1: Selecting Built-in Preset AvatarSample_I

  1. In the VRoid Studio model selection screen, select and open AvatarSample_I from the built-in sample presets list.

Select AvatarSample_I ▲Figure 2-8: Selecting AvatarSample_I from the sample models list

Step 2: Removing All Hair, Outfits, and Accessories

Just like the Base model, remove all model-specific decorative items.

  1. Open the Hairstyles tab and unequip all hair items.
  2. Open the Outfits tab and unequip all clothing, shoes, socks, etc.
  3. Open the Accessories tab and confirm that no accessories are equipped.

State with AvatarSample_I hair, outfits, and accessories removed ▲Figure 2-9: State after removing all hair, outfits, and accessories from AvatarSample_I

  1. From the top-left menu, save the file as SampleI.vroid.

Step 3 (FBM Side): VRM Export Settings and Value Match Verification

  1. Click the export icon in the upper right and select Export VRM.
  2. Under Reduce Polygons in the right panel, turn OFF all checkboxes and confirm all sliders are set to 0.
  3. Check the Polygon count, Material count, and Bone count in the Export Info, and verify that they match the values verified on the Base (BasicFemale) completely.

AvatarSample_I polygon reduction OFF and value match verification ▲Figure 2-10: Turn OFF polygon reduction and verify that polygon, material, and bone counts are identical to BasicFemale

[!CAUTION] If the values do not match the Base model, unremoved hair parts, accessories, or clothing may remain, or polygon reduction options may be enabled. Be sure to return to previous steps and verify.

Step 4: Exporting VRM 1.0

  1. Click the Export button in the lower right.
  2. In the “VRM Settings” dialog, configure the following:
    • Export Format: Make sure to select VRM1.0.
    • Avatar Name (Required): Enter SampleI.
    • Creators (Required): Enter an author name.
  3. Execute export and save the file as SampleI.vrm.

VRM 1.0 export settings (SampleI) ▲Figure 2-11: Selecting VRM1.0 format and setting avatar name to SampleI

5. Summary of Base and FBM Deliverables

Through the steps in this chapter, the following files will be created. These will be used as input data in the next chapter (Figure Registration) and beyond.

Role VRoid Project File Output VRM File VRM Avatar Name FBM Axis Name in ShapeSync
Base (Reference Base Body) BasicFemale.vroid BasicFemale.vrm BasicFemale (None, as it is the baseline)
FBM (Body Shape Deformation) SampleI.vroid SampleI.vrm SampleI SampleI

Terms of Use for VRoid Studio Sample Models

6. Common Issues and Solutions (Troubleshooting)

Q1. Polygon, material, or bone counts do not match between Base and FBM

Q2. Topology mismatch error (FBM topology does not match Base) occurs during Generate in subsequent steps

Q3. Exported as VRM 0.0 by mistake

← Back to Tutorial Index ｜ ← Chapter 1: Installation

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