We present a method of X ray diffraction measurement in which the depth penetration is controlled during the measurement. The method consists of adding a third rotation to the sample. This omega rotation, normal to the incidence plane, allows to keep a given penetration depth of X-ray. Correction of intensities and localisation of the measurement direction in the sample reference are presented. The limitations of this method are presented and discussed. Some potential applications are presented, particularly, we discuss the capability of this technique to be used for different applications like quantitative phase analysis (QPhA), X-ray stress analysis (XSA) or pole figure (PF) measurement when the sample present a gradient.