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Limitations

Everything here is also reported by the tool. This is the same information in one place.

Not converted at all​

  • VRChat contacts. Basis has no contact system, so anything driven by touch is dropped.
  • VRChat raycasts. Nothing in Basis fires a ray into animator parameters.
  • Where a VRM looks. Its eye offset carries across as the Basis eye position, but the aiming does not: Basis drives gaze itself. The renderers a VRM hides from its wearer are reported rather than converted. See VRM.
  • A VRM's metadata. Its title, author and permissions are shown before you convert, and Basis has nowhere to keep them.
  • Two-axis and four-axis puppets.
  • Animation that moves or scales something over time. Only rotation is baked, so a toggle or a layer that animates anything else over time is reported rather than half converted (vixxy.notSimple, motion.notRotation). See Authored motion.
  • Expression parameters as a system. Vixxy controls hold their own state, so there is no parameter list to recreate.
  • Custom animation layers, gestures, sitting and IK poses.
  • Anything that only exists while an animator runs. Gesture blends, radials that scrub a clip through motion time, layers that interact. The animator is read to find the constant values a menu entry sets, never run. Such layers are named in the report (fx.layersUnread, motion.motionTime).
  • Overrides made on a scene instance. A prefab variant's overrides and a nested prefab's overrides are read from their files. A value changed on the instance in the scene, on a component that arrives as a missing script, is not.

Converted with a caveat​

  • Two physics settings are fits, not conversions. See Physics.
  • Wide angle limits are dropped rather than clamped to something tighter.
  • A head chop applies in VR and on desktop alike, whichever VRChat limited it to.
  • Eyes turn up to 25 degrees on every avatar. Basis has no per-avatar limit; a VRM built for 10 degrees shows white when its eyes track past that.
  • Global PhysBone colliders stay local. Basis makes hands, arms and feet global on its own.
  • Material properties are applied through a property block, which covers every material on a renderer. A renderer with more than one material is reported.
  • Modular Avatar toggles are rebuilt only when a single parameter of the avatar's own steers their layer.
  • A toggle that waited on a VRChat parameter no longer waits. IsLocal, InStation, Seated and the rest have no Basis equivalent, so a control guarded by one switches whenever it is used. The report names the guard that was dropped.
  • Authored motion carries rotation only. A baked Basis motion clip holds nothing else, so a clip that also moves or scales something keeps the turning and reports the rest.
  • A baked motion clip is a project asset, so an undo removes the components a conversion wrote but leaves the clip on disk.
  • A radial puppet becomes a slider between the two ends of its blend tree. Vixxy interpolates in a straight line between choices, so motions the tree held in between are approximated by that line.
  • A VRM fills five of the fifteen visemes. It names the vowels and no consonants, so the mouth moves on aa, E, ih, oh and ou and holds still on the rest.
  • None of the three VRM constraints is exact. VRM's rotation constraint copies a delta from the source's rest pose, VRM's aim states no up direction, and nothing in Basis copies rotation about a single axis the way a roll constraint does. See VRM.

Where the data comes from​

Component data is read from prefab files, because in a Basis project the VRChat components are missing scripts and only a file still holds their values. What was added in the scene rather than in a prefab is read from the saved scene file. Things that follow:

  • The scene has to be saved. Components added in the scene are read from its file, so an unsaved scene reports scene.unsaved and a scene with unsaved changes scene.dirty. An avatar placed from its FBX with everything added on the instance reads this way.
  • Unpacking a prefab in the Basis project drops its data. A component whose script is missing keeps its values only while it comes from a file. Convert the linked instance instead of unpacking it. A scene saved where the scripts existed keeps everything added in it.
  • A file has to be text. A binary prefab is source.notText and a binary scene scene.notText. Unity will not save a prefab whose scripts are missing, so a prefab's switch to Force Text happens in the project where the scripts are installed.
  • A prefab variant is read from every prefab above it as well, since its own file holds only its overrides. The report names the base as source.prefabVariant.
  • A prefab nested inside another is read from its own file, with the outer prefab's overrides applied to it first, including references that point back into the outer prefab. An avatar that keeps its armature clean and puts every component on a prefab of its own reads the same as one that does not.
  • A collider added in the scene and assigned to a PhysBone inside a prefab is not found: physics.collider.unresolved. The other direction, a scene PhysBone naming a prefab collider, is.

A copy built by VRCFury cannot be read. Convert the original avatar: see VRCFury.

An imported .vrm is the exception. It is binary rather than text, and UniVRM has to be installed for it to import at all, so its components are read directly. See VRM.

Things a conversion does not touch​

Materials and shaders, meshes, the avatar's animator, and anything Basis fills in itself when the BasisAvatar inspector is first opened.

Shaders​

Basis renders with URP. A material whose shader does not run there is swapped at load for Universal Render Pipeline/Lit, keeping its base texture, colour, normal, metallic and occlusion maps. What an avatar's materials need depends on the shader:

  • lilToon regenerates its shaders for the project's pipeline on import. No material change.
  • Silent Cel Shading has a URP pass in the same shader file. No material change.
  • MToon for VRM 1.0 is chosen for URP by UniVRM when the .vrm is imported. VRM 0.x MToon has no URP shader and imports as unlit.
  • Poiyomi 10.0.20 and later ships its URP shaders as a separate package, Poi.Toon.URP, for Unity 6. They are separate shaders, so each material has to be switched to the URP one. A Poiyomi material whose shader is missing offers Switch to latest Toon in its inspector, which picks the URP shader in a URP project. A locked material has to be unlocked first.

Basis keeps its own list of shaders known to work at docs.basisvr.org.

OSC​

Basis listens for OSC on port 9000 and routes /avatar/parameters/<name> to the Vixxy control whose address is <name>, on an avatar carrying HVR Basis Comms's Automatic Face Tracking or OSC Acquisition component. A converted control's address is its parameter name, so an app that drove the parameter on VRChat drives the control here.

Basis reads float arguments only; bool and int messages are dropped.