An extended standalone version of the 3Dtexture Creator by SIsilicon as part of the Godot Volumetrics Plugin at https://github.com/SIsilicon/Godot-Volumetrics-Plugin
Be sure to reimport created texture as Texture3D (from the import tab).
Iranon/Godot-3DTexture-Gen
An extended standalone version of the 3Dtexture Creator by SIsilicon (part of the Godot Volumetrics Plugin at https://github.com/SIsilicon/Godot-Volumetrics-Plugin)
GLSLMIT