Viewpoint transitions have been shown to improve users' spatial orientation and help them build a cognitive map when they are navigating an unfamiliar virtual environment. Previous work has investigated transitions in single-scale virtual environments, focusing on trajectories and continuity. We extend this work with an in-depth investigation of transition techniques in multiscale virtual environments (MVEs). We identify challenges in navigating MVEs with nested structures and assess how different transition techniques affect spatial understanding and usability. Through two user studies, we investigated transition trajectories, interactive control of transition movement, and speed modulation in a nested MVE. We show that some types of viewpoint transitions enhance users' spatial awareness and confidence in their spatial orientation and reduce the need to revisit a target point of interest multiple times.