Yes, walking through walls has obviously nothing to do with clippend polygons. Also the Descent engine restrictions don't apply for A5 models. So there must be a different reason for both problems.
If you can't find the reason, I suggest that you both contact the Conitec support about your problem (acknex_d@conitec.net). Include a detailed description, screenshots and if possible, the offending level or model. The time limit for support does not apply if the problem you have could be an engine bug.
[This message has been edited by jcl (edited 26 April 2001).]