A computer system that assists the user of computer drawing programs to accurately place new objects on a drawing is described. The system establishes and displays dynamic gridlines according to objects already placed on the drawing. As a new object is dragged for placement on the drawing, the system analyzes the areas around the new object for already-placed objects. The system then determines the spacing between the already-placed objects and indicates to the user where the dragged object should be placed to maintain the same spacing as the objects already placed on the drawing.