Suggestions

[Petie]

Getting zip downloaded every page view is indeed a problem. How about the plugin first shows the regular preview image and there could be a button to load the zip file for further examination. Once it's downloaded, the plugin can show the object if it can or error message that it couldn't process it. Then there could be another button to download the already downloaded data to the user computer. This should be about the same strain on the server.

I found this http://stackoverflow.com/questions/23599...irectories which is said to handle subdirectories in Zips so I will try a Flash project with OBJ files. Btw, I think it should be possible to render geometry (without textures/materials) relatively easy.

One question though, are they all Zip files or are there Rar, 7z etc. as well?

I'd still much rather do this without Flash. HTML5 canvas/JS would be preferred. Still probably worth experimenting with. And your idea may reduce strain on the server enough to make it feasible.

They're all .zip archives. We used to accept other formats but have since re-archived all non-zips and changed the system to only accept zip files.

Ok, I think I found something worth checking out.

There is a way to do all this using only JavaScript. 
There are two scripts on the web:
zip.js - Let's you zip, unzip files directly on the browser (I think it works in the background)
three.js - To view 3D models online

Since I'm using the computer at work I've still haven't had much time to see how to make these two scripts work together... and if it can't be applied to this site, no problem, at least I've learned something.

I haven't looked at them yet but it seems promising given that it's all JS. Hopefully we can work something out because I really would love to see 3D models directly on the site.