kreator, yeah the server has a lot of limitations in place. Ever wonder why oftentimes you get a "can't connect to database" error, yet the rest of the website runs fine? The host only allows ten simultaneous connections to the mysql database
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The attachment problem is a hurdle I ran into before as well, wanting to use a pre-subdivided robin for the examples (only 2.4mb). File uploads are being limited to 2mb by the webhost. I emailed Steve about it, no guarantees though.
I would like to use zip files. The zip file feature isn't three.js related, but rather it's just a server-side processing issue. I didn't implement it yet because there are a lot more factors that come into play. [edit] I'm looking at client-side alternatives now[/edit]. Rest assured, it is on my to-do list!