Missing symbols means that one or more of the zip files was either not extracted at all, or extracted to the wrong location.

Common problems here is to let your unzip utility make a directory based on the name of the archive and then put everything inside this extra directory. This is a common behaviour, and causes havock when cc3+ looks for the files since they won't be where expected.

Best way to check for such things is to click once on one of those symbols, and then go to Symbols -> Symbol manager and find the symbol there. Select it and click list. This should reveal the expected file path of the image. Remember that @ refers to the CC3+ data directory. Now dig in there and look for the symbols. You'll probably find them inside some extra directory. If you fail to find them at all, it means you skipped a .zip file. The path should help you pinpoint which.

In reference to the small buttons, you know you can change their size from :TOOLSICON:?

I don't think it is. The options regarding this is found in Tools -> Options -> Editing Options, but Tab is ind of an override for the default options, it doesn't actually change the options set here.

I would consider one of these approaches here:

1. Join paths to polys and create a multipoly of your floor before putting it into perspective. The disadvantage with the multipoly approach is that it is difficult to edit after the fact.
2. Split up the original trace into separate polygons for the rooms and corridors. This gives you a lot more surfaces, but it is easier to handle and edit. This approach will require a bit more processing for your trace before turning it into perspectives though.

The issue that occurs here is that because of memory constraints, CC3+ cannot compute the entire high-resolution map in memory at the same time for the export, which is why it exports in multiple passes, each pass rendering a part of the map.

Unfortunately, effects from entities outside of the current rendering part won't be considered, such as shadows from entities far away. There is a certain overlap to handle the closer but right outside things, but considering effects from everything in the map is impossible due to the aforementioned resource problem.

However, you can change the default size of these render chunks, causing CC3+ to render much more of the map in one go. This is done by typing in EXPORTSETMPPP on the CC3+ command line and hitting enter. The command line will then ask for the number of pixles, type in the value 40000000 (The current value, shown in brackets is probably 4000000, keep your zeroes straight). and hit enter. Depending on your export resolution, you will export the map in much fewer passes, perhaps even just a single pass.

Note that if this isn't enough, the other solution is to either consider using shorter shadows, avoiding the problem, or manually creating them using a partially transparent polygon.