Hi! I think this tool will be useful, please take a look.
Most important feature for people here might be Spine atlases repacking.
And of course it's possible to combine multiple textures into one for more optimal memory use.
Download it for free on www.spriteuv.com
Important notice: Make sure your export atlas path and export group path for repacked Spine data is the same.
General description:
Extremely tight packing. Allows for an additional 30%-90% free space compared to square or other concave packing algorithms.
Easy to use. Drag and drop image files (.fbx, .json (Spine animation), .png, .tiff, .tga, .psd) -> Select folder for atlas and meshes -> Hit Build
Per sprite settings. Precise mesh shape adjustment for each sprite for the best result.
Export mesh to FBX, UNITY SPRITES, COLLADA, OBJ or JSON. Exported meshes are ready to be immediately used in any modern game engine or 3D application.
Project settings file saved in a simple JSON format.
Command line interface.
Key features
Auto Mesh Generation. Optimal Concave or Convex mesh generation from sprites.
Custom Meshes. Precisely define sprite meshes for the best result or future manipulations.
Mesh tessellation. Useful for the mesh run time deformation, like cloth, verlet or any other.
Multi-texture export. You have the ability to create textures with different data but share the same UV coordinates and mesh shape. Great for applications such as normal maps, glow maps, etc.
3D object UV Map repacking. Repack UVs in FBX files and combine multiple textures into one.
Spine animation atlas repacking. Repack / combine multiple Spine animation atlases into one texture
Import formats
PNG
TIFF
TGA
PSD
FBX
JSON (Spine animation)
Export mesh formats
FBX
COLLADA
OBJ
JSON
UNITY SPRITE ASSET
Export atlas formats
PNG
TGA