When I try to decimate just the visible sub-tools, I get a prompt (NOT visible) for EACH invisible sub-tool while “Pre-process All” is running. I have probably hundreds of invisible sub-tools. I can only imagine how long that would take to click through, because I always give up after about 40 clicks! I just updated from 4R8 to 2019 (I know, don’t ask), so I don’t know if this is something that existed in 2018, or if it’s new. It never happened to me before.
Please help!
You need to update to 2019.1.1 - see “How to Update” in the first post in this thread:
https://www.zbrushcentral.com/t/zbrush-2019-1-now-available/216270