We analyse use of real-time video in virtual environments in interaction between real and virtual humans. We implemented our ideas in a networked collaborative virtual environment system, VLNET and in an augmented reality setup. This paper presents three distinct case studies. The first one is a transatlantic demonstration, where distant users interact with virtual humans through several video tools. Our second case study is development of an augmented reality test bed. The third one presents a distributed augmented reality application, where participants share a mixed environment with real and virtual elements