First of all, I wanted to ask if there is an easy method to detect and control errors in the program. Something like an 'if(error){}' command, to display something and then continue, as nothing happened. polymake extensively uses exceptions for reporting errors. How you catch them depends on the co...

Well, it's a known issue and there is even a pending ticket about it. Unfortunately, I can't give a reliable prediction as of when it's going to be fixed. It haven't got a high priority so far. In the meanwhile, you might want to play with the script apps/polytope/scripts/visual_unbounded (which BTW...

... But for transparency=0, it is still now opaque.

transparency=0 means opaque, where is the problem?

If you are going to repeatedly look for faces in the same simplicial complex, you would save quite some time if you load the complex' facets into a FacetList object once and then query for face containment using its method findMax. For a one-off query, however, a simple loop as suggested by Michael ...

You might also find useful the following in-depth scripting manual: http://www.polymake.org/doku.php/scripting/start.

So if the syntax you try does not work, it is always possible to specify the indices in an extra variable ... That way you can directly use the data type you find in the documentation. It will surely be also helpful if we include a remark in the documentation of Array that it almost always can be e...

I would have attached a pdf/svg/html file from our old documentation to explain this in more detail if I would have been allowed to upload an attachment of this kind.

A much better idea would be to convert the old documentation into a proper Wiki page, isn't it?