You have a mesh and you want to generate a new mesh at runtime? You could modify the existing mesh, setting a new texture (which is game toolkit specific) and UVs. Or, you can create a new linked mesh, which will be affected by the deform keys in animations for the source mesh (but must be in the same slot). For that, see MeshAttachment parentMesh
. You can look at SkeletonJson or SkeletonBinary for how new attachments are created and configured.
If your attachments are in Spine (I asked but you didn't provide an answer), then you can create a linked mesh in Spine:
Meshes - Spine User Guide: Linked meshes
Note it is often better to use a weighted mesh rather than deform keys.