Purpose This paper aims to present a new methodology to optimize the support generation within the FDM process. Design/methodology/approach Different methods of support generation exist, but they are limited with regards to complex parts. This paper proposes a method dedicated to support generation, integrated into CAD software. The objective is to minimize the volume of support and its impact on a part's surface finish. Two case studies illustrate the methodology. The support generation is based on an octree's discretization of the part. Findings The method represents a first solid step in the support optimization for a reasonable calculation time. It has the advantage of being virtually automatic. The only tasks to be performed by the designer are to place the part to be studied with respect to the CAD reference and to give the ratio between the desired support volume and the maximum volume of support. Research limitations/implications In the case studies, a low gain in manufacturing time was observed. This is explained by the honeycomb structure of the support generated by a common slicing software whilst the proposed method uses a "full" structure. It would be interesting to study the feasibility of an optimized support, with a honeycomb structure but with a preservation of the surface which is in contact with the part. Originality/value This solution best fits the needs of the designer and manufacturer already taking advantage of existing solutions. It is adaptable to any part if the withdrawal of support is taken into account. It also allows the designer to validate the generation of support throughout the CAD without breaking the digital chain.Read less <