Forming a 3D representation of an object using a portable electronic device with a camera. A sequence of image frames, captured with the camera may be processed to generate 3D information about the object. This 3D information may be used to present a visual representation of the object as real-time feedback to a user, indicating confidence of 3D information for regions of the object. Feedback may be a composite image based on surfaces in a 3D model derived from the 3D information given visual characteristics derived from the image frames. The 3D information may be used in a number of ways, including as an input to a 3D printer or an input, representing, in whole or in part, an avatar for a game or other purposes. To enable processing to be performed on a portable device, a portion of the image frames may be selected for processing with higher resolution.