With the rectangular polyline still selected, click the Convert Polyline edit button, and in the Convert Polyline dialog that displays, choose the 3D Solid option, then click OK.Next, drag the top left corner down to create a slope, as shown in the image below.With the rectangle still selected, click the Add Break edit button and click along the top edge of the rectangle to place a break at that location.Click on the top edge of the polyline to select it, then click on the temporary dimension that displays between it and the bottom edge to specify the height above the deep end that you would like the shallow end to be.This rectangle will form the shallow end of the pool, as well as the slope to the deep end. In the back clipped cross section view, select CAD> Boxes> Rectangular Polyline from the menu, then click and drag to draw a rectangle along the bottom part of the pool.Select 3D> Create Orthographic View> Back Clipped Cross Section, then click and drag a camera arrow that runs perpendicular to the slope that you wish to create.