A method for controlling a co-presence virtual environment being a virtual environment with more than one user (130, 150), the method being performed by a co-presence manager (120, 121, 122) of a computer system configured to generate or manage virtual environments, the co-presence manager (120, 121, 122) being configured to perform functions and operations that manage restricted spaces and permitted spaces for avatars corresponding to users (130, 150) in the co-presence virtual environment, wherein the visibility of one or more safe spaces (430, 440, 445, 450) can be turned on or off by a user that defined them, or by other users participating in the co-presence virtual environment, and the method comprising: determining a first avatar's (310; 420) restricted space in the co-presence virtual environment, the first avatar (310; 420) corresponding to a first user of the co-presence virtual environment, wherein the first avatar's restricted space is defined based on a safe space (430, 440, 445, 450) that has been defined by a second user; receiving user position data from a sensing system including an inertial measurement unit and an image sensor capturing body part motion of the first user of a first computing device associated with the first user and determining the first avatar's location within the co-presence virtual environment based on the user position data, and receiving, by applications, data regarding a representation of said body parts, wherein the first avatar's (310; 420) restricted space is defined based on a plurality of safe spaces (430, 440, 445, 450) of the second user that have been defined by the second user of the co-presence virtual environment, the plurality of said safe spaces (430, 440, 445, 450) corresponding to body parts of the second user and having different sizes; determining that the first avatar's location is within the first avatar's restricted space, and communicating, in response to the determination, first co-presence virtual environment modification data to the first computing device; and communicating, in response to the determination, second co-presence virtual environment modification data to a second computing device associated with a second user of the co-presence virtual environment, wherein the second co-presence virtual environment modification data includes instructions for the second computing device to make a portion of the first avatar (310; 420) invisible, or rendered in outline, as translucent, or using a different color scheme, in a rendering of the co-presence virtual environment by the second computing device. determining a first avatar's (310; 420) restricted space in the co-presence virtual environment, the first avatar (310; 420) corresponding to a first user of the co-presence virtual environment, wherein the first avatar's restricted space is defined based on a safe space (430, 440, 445, 450) that has been defined by a second user; receiving user position data from a sensing system including an inertial measurement unit and an image sensor capturing body part motion of the first user of a first computing device associated with the first user and determining the first avatar's location within the co-presence virtual environment based on the user position data, and receiving, by applications, data regarding a representation of said body parts, wherein the first avatar's (310; 420) restricted space is defined based on a plurality of safe spaces (430, 440, 445, 450) of the second user that have been defined by the second user of the co-presence virtual environment, the plurality of said safe spaces (430, 440, 445, 450) corresponding to body parts of the second user and having different sizes; determining that the first avatar's location is within the first avatar's restricted space, and communicating, in response to the determination, first co-presence virtual environment modification data to the first computing device; and communicating, in response to the determination, second co-presence virtual environment modification data to a second computing device associated with a second user of the co-presence virtual environment, wherein the second co-presence virtual environment modification data includes instructions for the second computing device to make a portion of the first avatar (310; 420) invisible, or rendered in outline, as translucent, or using a different color scheme, in a rendering of the co-presence virtual environment by the second computing device.