Sensa Unity package
English | 简体中文
Sensa Unity components store tracking and parameter settings. Avatar builds generate native Contacts, constraints, FX animation, parameters and menus from those settings. Avatars with existing OGB/SPS parameters can also configure mappings directly in the desktop app.
Interactive parameter diagrams show the geometry and parameter prefixes. Browse geometry and values independently, including offline. An offline copy is available at docs/parameter-geometry.html in the repository and desktop distribution.
Install and choose a language
- Use a VCC/ALCOM Avatars project with the Unity version and VPM dependencies required by
package.json, including NDMF 1.5.0+ and Modular Avatar 1.10.0+. Install official VRCFury separately when using its SPS authors. - Extract the Unity ZIP, then use Package Manager → Add package from disk and select
package.json. Use VCC/ALCOM to install the listed VPM dependencies. - Sensa Inspectors and Preferences → Sensa offer Automatic, English and 简体中文. Explicit choice persists for the editor user. Automatic prefers the actual Editor UI language, falls back to the OS if that API is unavailable, maps Chinese variants to Simplified Chinese and otherwise uses English.
- Editor menu registration paths and serialized/OSC identifiers remain stable English IDs. Avatar Expression Menu labels use the author's language at build time; they do not translate separately for each wearer.
The historical VPM index may offer an older package. Development previews do not update that stable index; check the installed version before applying this guide. The ZIP contains no VRCFury, paid model, Worlds SDK or runtime Udon. The build copy receives native components, and the author scripts are removed. Install the separate lab sources only in their matching project type.
Select a measurement route
| Route | Setup | Meaning |
|---|---|---|
| Existing OGB | Configure existing SPS/OGB and desktop mappings | Scalar Touch or radial depth estimate; external interoperability |
| SPS four-anchor tracking | Add Sensa → Automatic SPS Setup, or SPS four-anchor tracking and explicitly assign Target | Root position relative to the Avatar root, in AvatarRootLocal authored units |
| Contact direct tracking (SDK Beta) | Choose Contact direct tracking (SDK Beta) in automatic setup, or add its prefab and explicitly assign Target | Dedicated Sender/Receiver; root coordinates in metres and relative SDK velocity; requires advanced Contact parameters |
| Shader root capture | Add Shader Root Capture (Experimental) or SensaShaderCapture.prefab, and assign Target |
AvatarRootLocal position, X/Z-axis vectors and Avatar world scale encoded into a monochrome image and read by the desktop bridge |
| Independent Point/Handle/Pose | Select local landmarks or matching paired markers | Separate experiments with their own protocols and freshness rules |
All three root prefabs accept an Avatar bone/empty-object Transform, SPS, Sensa Component or native Contact. Instances of SPS four-anchor tracking and Contact direct tracking default to Root; rename duplicates to unique instances, and an empty collision channel is derived from that name. Menu creation fills an unambiguous selected target; check Target before building.
New automatic setups use Exclusive, initially Off. Dedicated permits simultaneous measurements. Target selection, native SPS activation, desktop input activation and device connection are separate controls.
Follow a bone with a reference plane
Tracking Frame and Shader measure relative movement between a target and reference on your own Avatar. For interaction between Avatars, configure paired SensaPoseSocket/SensaPosePlug tracking, using the receiving Socket as the shared reference.
Use GameObject → Sensa → Tracking Frame or SensaTrackingFrame.prefab. Choose a bone, SPS root, Sensa component or native Contact in Reference frame, then adjust position and rotation offsets. The Scene shows the plane and its depth direction: +Z is forward, +X right and +Y up. Six axis buttons and move/rotate handles help place it.
Choose SPS four-anchor or Contact direct tracking. A frame named Frame publishes Frame_Origin, Frame_Forward and Frame_Right; its default axis-marker spacing is 0.2 authored Avatar-root units. The measured frame follows the reference's position and rotation while retaining Avatar-root scale. In the desktop workbench, the Follow a moving plane template combines these readings with a target position to obtain signed depth and lateral offset. Fields, generated components and setup
How settings become a built Avatar
All author scripts implement IEditorOnly. One NDMF plugin generates Contacts and temporary animation/parameter/menu inputs in Generating before Modular Avatar, which then merges them. Generation removes the author scripts while retaining their hosts, reference Transforms and native measurement components. Keep hosts as ordinary GameObjects; reserve the EditorOnly object tag for purely editorial helpers removed as an entire hierarchy.
An SDK checkpoint verifies that authors were processed. If NDMF build processing is disabled or another tool inserts Sensa authors later, the build lists remaining types so you can adjust setup and ordering. See the Unity build guide for phases, official sources and basic-component behavior.
What does SPS four-anchor tracking generate?
Sensa/SPS/<id>/P0 through P3 are four Proximity values; Sample is 0 when invalid and advances through n/32 (n=1…32) while active. Four known noncoplanar anchors reconstruct a local point. They share center (0,1,0), half-span 0.35, receiver radius 2 and dedicated marker radius 0.001. Only Self is generated, at five Contacts per target.
Check the green common-coverage slices in Unity Scene: a point must be inside all four receivers to be positioned. Small orange regions indicate saturation blind spots near anchors. Shader instead shows its full encoding box and has no Contact radius.
When geometry or generated components change, rebuild the Avatar and use the desktop app with the matching shared protocol. Replace the generated components as a complete set.
Coordinates use Avatar-root local units. Common world movement leaves them unchanged. Uniform scale is required; build checks and internal ScaleFactor guards enforce the world-radius limit. The display box is not guaranteed Contact coverage. Geometry, public/control parameters and stops
Inspect before allowing motion
Apply OSC mode in Sensa and open OSC → Experimental diagnostics → Local points and roots. Pin the actual instance/source, inspect changing Sample and valid coordinates, capture two endpoints, then inspect and save the mapping draft. Experimental permission defaults off and is separate from input activation.
Sample indicates ongoing publication; actual-client checks also inspect target identity, field consistency and measurement accuracy. Missing/invalid/expired observations stop motion. Old Sensa SPS paths are unsupported: rebuild the Avatar and mappings.
Unit, package and mock-transport checks record their respective scope. Unity Editor, uploaded-client behavior, VR grabbing, desktop/HMD capture and device response receive separate acceptance checks. QuickStart remains an internal synthetic lab fixture.
Build pipeline · Automation · Dependencies and limits · Shader capture