If someone says "the cup is in front of the teapot", is the cup between the speaker and the teapot, is the cup at the spout end of the teapot, or both? In order to resolve this ambiguity, you would need to know whether the speaker was using a reference frame based on his/her viewpoint (deictic) or on the objects in the scene (intrinsic). As well, why did they locate the cup in relation to the teapot, and not the other way around? The study presented here was an investigation into which factors play an important role in the decision to use a deictic or an intrinsic reference frame, as well as which factors influence reference object selection. When objects were presented in a functional orientation, participants were more likely to use an intrinsic versus a deictic reference frame than when objects were presented in a non-functional orientation. Object orientation did not appear to influence the choice of reference object, but participants were much more likely to select an object as a reference if it was generally perceived to be the more stationary object of the pair. This research is part of a project involving the design of human-computer interfaces for collaborative spatial reasoning in 3D virtual workspaces.