Nested Explorative Maps: A new 3D canvas for conceptual design in architecture

•A recursive solution for creating a 3D sketch by drawing on semi-tranparent surfaces, themselves extruded from 2D footprints.•A system composed of a sketching interface with the associated vizualisation and editing tools for a real-time interaction.•A method based on local attractions to dense stroke regions to enable interactive navigation through the alternative designs.•This navigation drive displacements plus free-form deformation of the nested construction surfaces carrying the user strokes.