The general problem of software and hardware interface has been discussed since the first personal computers had appeared on the market. Interface solutions, proposed by the CAD software producers themselves, have been deeply criticised. In fact, learning how to use the software means how to operate its interface. In the process of software developments, interfaces became'second languages', which are to be learnt by the user. This is a real problem especially for the beginner. The problem is even more complicated in case of interfaces for many users. They should help in the processes of computer networks based cooperative design. In this paper we try to juxtapose the main features of user interfaces in CAD, especially ones for collaborative work. The most important problems were detected, and conclusions were made with an aim to research interfaces adequate for architect's work in the future.