Skeleton data is separate from the images used. If you want to show your skeleton larger, you can scale the skeleton data at runtime when you load it, see SkeletonJson scale
. This way you can use the same skeleton data with different sized images/atlas.
However, if you don't actually want to show your skeleton larger, you just want to use higher resolution textures so an animation which scales up the skeleton doesn't look bad, then you don't need to use SkeletonJson scale
just load the same skeleton with the larger atlas. The skeleton will render at the same size, but the images it uses will be higher resolution so they won't look bad zoomed in.
You can write your own AttachmentLoader which doesn't fail if a region cannot be found in the atlas. This way you can have a higher resolution atlas which only has the assets needed for the one scene. The unnecessary attachments will still be loaded, just not configured with an atlas region, which is unlikely to be a problem.
An AttachmentLoader can return null for an attachment, avoiding creating the attachment completely, but I think this may cause some types of animation timelines to fail to load. Eg, a DeformTimeline expects to be able to find its mesh attachment.