Volute????
To me a "volute" would be the spiral part of a greek column at it's top piece (the caital). But you might mean a coil of some sort for mechanical.
IN EITHER CASE, use the arc command.
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The spline would be fine BUT in AutoCAD 13, the spline element would always corrupt a drawing once you mirror it a couple of times or hatch it when its part of some shape. At least this was my past experience.
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Just use the "arc" to do a part of the coil and then just "array" (copy/ rectagluar motion) the continuous pieces.
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I hope I anserwed the questions.
Rich@LG (Arch)
