Then create the top and pull the middle line somewhat forward for a more comfortable seating.

Make the corners round.

Then select the outer Edges use the Round Edges by Bezier and select the preferred rounding (group the whole model).

Then make another box with rounded edges on the underside of the box (group it).

Place it over the seating and select the models, then context-click and select Intersect with Model. Then delete the box that we just used.

Select the line just created with the Intersect with Model operation. Use Pipe Along Path to create the round piping along the seating. Note: Set inside diameter to 0.0mm.

Then create the right part in the same way as the seating.

Use Round Edges again (create a group of it).

Create a box and place it around the model, then intersect with model.

Then delete the box and select the created lines again and use Pipe Along Path to create the piping.

Copy the left part to the right.

Group everything.

Create the line for the underside of the sofa.

Then use Pipe Along Path again to create the underside.

Then copy it to the right part and you are done.

.:GFXZoOM|source: sketchucation.com::.