Blind people clearly also have a spatial concept of their environment. Other sensory modalities than vision are important in giving information about space, such as movement, touch and sound. However a way to represent spatial information via non-visual modalities in a pictorial format for blind people, is not as clear as the seeming match between retinal image and visual picture. The current paper explores to achieve this based on blind people's representations of three dimensions on essentially two dimensional surfaces. Surface based models are based on points in 3D space connected by lines which in turn form edges of polygons, the surfaces which distinguish these models.
Many faces connected by their edges form an object.
In the general case described here, it is not possible to make statements about the inside of the object. Objects are considered as hollow. We can render nice images from our models but we can not build these models based on an image. Computer vision is still an unsolved problem. The models do not have a meaning.