1. A method at least partially implemented by a computing device, the method comprising: using a computing device to identify a set of vector primitives from a 2-D sketch wherein the vector primitives comprise one or more of a set of line segments and a set of curves; generating a graph structure that indicates spatial relations between respective ones of the identified vector primitives; using the graph structure to classify lines as left, right, or vertical and identify line segment vanishing lines; identifying a set of line segment endpoint junctions; classifying each line segment endpoint junction based on a angle of line segment intersection and a number of intersecting lines at each line segment endpoint junction; automatically generating a 2.5D geometry model from the vector primitives on the computing device; receiving user input corresponding to one or more of lighting, texture, color and geometry modification of the 2.5D geometry model, wherein the user input is user drawn hatch strokes for calculating light position, direction, and intensity; computing a matched texture index by calculating line-likeness for the user drawn hatch strokes, wherein the line-likeness calculated based on a direction co-occurrence matrix; computing lighting position, intensity and direction from the position and density of the user drawn hatch strokes, wherein lighting intensity is calculated by: 
 I =k d I i cos(θ), wherein l is intensity, k d is a reflectance coefficient, I i is the intensity of the light source, and θ is the angle between the normal of a surface and the light direction; and rendering the 2.5D geometry model for presentation to a user on a display.