Techniques are presented for constructing a digital representation of a physical environment. In some embodiments, a method includes obtaining image data indicative of the physical environment; receiving gesture input data from a user corresponding to at least one location in the physical environment, based on the obtained image data; detecting at least one discontinuity in the physical environment near the at least one location corresponding to the received gesture input data; and generating a digital surface corresponding to a surface in the physical environment, based on the received gesture input data and the at least one discontinuity.