Using the Mode move.svgMove Tool in the Perspectives algebra 3Dgraphics.svg 3D Graphics View you may drag and drop free points. In order to move a point in the three-dimensional coordinate system, you can switch between two modes by clicking on the point:
Mode x-y-plane: You may move the point parallel to the x-y-plane without changing the z-coordinate.
Mode z-axis: You may move the point parallel to the z-axis without changing the x- and y-coordinates.