Start off with an arc for the front of the seat. For this model I am going to make it a fairly high polygon model so when you click the arc tool make sure to type 48 in the VBC (Value Control Box) before you draw the arc. Click on one side of the box then perpendicular on the other side. Finish the arc by drawing the bulge. You can eyeball this part then move the arc up or down to line it up the way you want it.
Now make your box with the arc into a component and name it “SEAT�. Copy it to the right and rotate that one 90 degrees and move it to the front of the seat on the reference image. Do the same with the top view, rotating the component copy and placing it at the front of the seat.
This will allow you to manipulate your modeling on 3 axis giving you better control over the desired shape.
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