Hi All

I am currently modelling a gearbox with some cooling fins around sides and under side (deeper on the underside). The fins are a different shape depending on if they are on the sides or the underneath. My question is, to get the basic shape, is there a way to extrude a box which follows two different profiles to get a kind of concertina effect? See badly illustrated sketch for what i mean. I have tried the sweep method but just makes a big mess of lines. I was thinking for this to work it would need to know a centreline of the extrude . . .

As ever any help on how this could be done would be gratefully received as its getting late . . . .