  Drawing tools for Virtual Reality (VR) enable users to model 3D designs from
within the virtual environment itself. These tools employ sketching and
sculpting techniques known from desktop-based interfaces and apply them to
hand-based controller interaction. While these techniques allow for mid-air
sketching of basic shapes, it remains difficult for users to create detailed
and comprehensive 3D models. In our work, we focus on supporting the user in
designing the virtual environment around them by enhancing sketch-based
interfaces with a supporting system for interactive model retrieval. Through
sketching, an immersed user can query a database containing detailed 3D models
and replace them into the virtual environment. To understand supportive
sketching within a virtual environment, we compare different methods of sketch
interaction, i.e., 3D mid-air sketching, 2D sketching on a virtual tablet, 2D
sketching on a fixed virtual whiteboard, and 2D sketching on a real tablet.
%using a 2D physical tablet, a 2D virtual tablet, a 2D virtual whiteboard, and
3D mid-air sketching. Our results show that 3D mid-air sketching is considered
to be a more intuitive method to search a collection of models while the
addition of physical devices creates confusion due to the complications of
their inclusion within a virtual environment. While we pose our work as a
retrieval problem for 3D models of chairs, our results can be extrapolated to
other sketching tasks for virtual environments.
