Rodrigues, VascoMendes, DanielFerreira, AlfredoJorge, JoaquimDias, Paulo and Menezes, Paulo2020-09-242020-09-242020978-3-03868-128-1https://doi.org/10.2312/pt.20151208https://diglib.eg.org:443/handle/10.2312/pt20151208If the interactions made on multi-touch surfaces can be moved to the air above them, a user will have access to a powerful tool. The possibility of tracking the hands' movement in mid-air, creates a world full of interaction possibilities. Despite having been created consolidated solutions for multi-touch interactions, these are limited to a bi-dimensional space, preventing the possibility of direct interactions on the visualization space. Some works were created to try and overcome this problem, however most of them use intrusive techniques, don't use stereoscopy or virtual reality or are lacking accuracy. This work had the objective to explore and evaluate which techniques allow to manipulate with precision 3D objects in mid-air, on a non intrusive semi-immersive/immersive environment. With this work it was possible to observe that the mid-air interactions in immersive systems are the most efficient and satisfying method for users, due to the direct manipulation of 6 degrees of freedom, which mimics the way with which we interact with physical objects.Manipulation3D ObjectsPrecision10.2312/pt.20151208100-107