RFC012 - Arbitrary attributes on Point/Corner/Face#

Around early 2020, @eliemichel

Referenced by RFC008.


What is now a “corner” was called “vertex” at the time (see RFC004), nonetheless this document uses the updated terminology.

Current Situation#

The OfxMesh structure has properties storing data buffers for per-point positions, per-corner point indices and per-face corner count.

Key limitations#

There is no mechanism for adding additional attributes to any of these attachments. This would be required to support texture coordinates, normals, or any other user-defined attribute that is typically manipulated in a non-destructive mesh processing workflow.



  • Remove hardcoded OfxMesh properties kOfxMeshPropPointData, kOfxMeshPropVertexData and OfxMeshPropFaceData.

  • Add kOfxMeshPropAttributeCount

  • Create a new struct OfxMeshAttrib (represented as a property set) with properties kOfxMeshAttribPropData, kOfxMeshAttribPropComponentCount, and kOfxMeshAttribPropType.

  • OfxMesh is no longer represented by a simple property set. We add a new optional argument propertySet to mesh effect suite entry inputGetMesh.

  • New mesh effect suite entry attributeDefine to define an attribute, prior to allocating a mesh.

  • New mesh effect suite entry meshGetAttribute to get an attribute from a mesh by name.

  • meshAlloc no longer take point/corner/face counts as input. Since its behavior depends on the attributes that have been defined before, we fully commit to its stateful idiom, and it reads this from the mesh properties (kOfxMeshPropPointCount, etc.).


  • The mesh representation is much more flexible and in sync with real life use cases.


  • This slightly complexifies the API.