A process for creating a surface model of a surface of a cavity wall (2), especially a heart chamber including the steps of: (a) accessing at least one three dimensional image data record of the cavity; (b) creating a preliminary deformable surface model of the interior surface or the exterior surface of the cavity wall for each three dimensional image data record; (c) dividing the surface of the preliminary surface model into surface segments; (d) defining volume segments each including one surface segment and extending radially inwards and/or outwards from their associated surface segment; (e) statistical analysis of the grey levels of the voxels present in the volume segments for analyzing the volume proportion of the cavity wall, in the respective volume segment; and (f) deforming the surface segments on the basis of the volume proportion thus creating a corrected surface model.