combining sublayers to reduce file size

Hi @Brook Bradbury,

Thanks for reaching out. It seems you are getting a warning as you have reached a limitation in Illustrator. This is expected behaviour. I would recommend you to try the second option suggested by @Scott Falkner to save the 29 sub-layer in a separate file and then embed & masking the file. This way, you will have full edibility freedom.

However, if you do not want to go to such lengths, I would suggest selecting all layers and going to the Object menu > Compound Path > Make. Also, I would recommend having a backup just in case you want to edit it later.

Kindly update the discussion if you still need assistance with it. We'd be happy to help.

Regards,

Anshul Saini

29 sub-levels? How did you create that? Are there already clipping masks in it? Compound shapes? Groups inside groups inside groups ...?

You will need to expand a few things and/or organize this differently.

As Scott suggested, it might help to group items. When you group, all of the grouped objects will go on to a single layer.

It also looks like you have a temendous number of anchor points. You could try selecting and choosing Object > Path > Simplify. Often you can reduce the number of anchor points with this command without any noticeable differnce in the objects.

Try grouping the items you intend to mask You could also save them to a separate file, place that and mask it.