Computer assisted method for the advanced design of bent parts of composite material using a computer assisted CAD system comprising the following stages: a) Supplying the 2D mesh model (11) of the part; b) Generating the 3D outer surface (19) of the part; c) Obtaining the 3D mesh model (51) by adapting the 2D mesh model (11) to the geometry of the 3D outer surface (19) by bending the contour lines (17) of the patterns (13) of the 2D model (11) with respect to some bending lines (23) set up in relation to a bending surface (31) similar to that of the tool provided for bending the part; d) Generating the solid model (53) of the bent part. The invention also relates to a computer program that when it is executed on a computer together with a CAD system it causes the execution of the method.