By using this grasshopper definition You can easily produce a parametric bench based on two or more sections and a single path. Simply define the inputs and the section solids of the bench will be produced. You can then use the curve sections to produce the bench.
Rail: Rail of the bench
N: Number of sections
Loc: Location of the main profiles
Profiles: Profiles of the bench
Point: Initial points from the profiles
Thickness: Thickness of the sections
Solids?: Produce the solids?
Sections: Resulting Sections
Solids: resulting solids