A computer implemented method for forming an optimized polygon based shell mesh for a three-dimensional graphics image, the optimized polygon based shell mesh provided as one of an occluder mesh and an occludee mesh in an occlusion culling process, the method comprising: obtaining the three-dimensional graphics image, the three-dimensional graphics image represented as an initial polygon mesh; determining a three-dimensional profile of the initial polygon mesh; resizing the polygon mesh a predetermined amount along a normal to the three-dimensional profile of the initial polygon mesh, the resized polygon mesh (406, 406') having a three-dimensional profile being larger than or smaller than the three-dimensional profile of the initial polygon mesh; if the three-dimensional profile of the resized polygon mesh is larger than the three-dimensional profile of the initial polygon mesh, forming the occludee mesh by adjusting the three-dimensional profile of the resized polygon mesh using a polygon optimization process, wherein the occludee mesh encloses a predetermined majority of the three-dimensional profile for the initial polygon mesh, wherein the occludee mesh comprises fewer polygons than the initial polygon mesh, and using the occludee mesh to determine polygon visibility within a scene to be displayed; and if the three-dimensional profile of the resized polygon mesh is smaller than the three-dimensional profile of the initial polygon mesh, forming the occluder mesh by adjusting the three-dimensional profile of the resized polygon mesh using a polygon optimization process, wherein a predetermined majority of the occluder mesh is enclosed by the three-dimensional profile for the initial polygon mesh, wherein the occluder mesh comprises fewer polygons than the initial polygon mesh, and using the occluder mesh to determine polygon visibility within a scene to be displayed. obtaining the three-dimensional graphics image, the three-dimensional graphics image represented as an initial polygon mesh; determining a three-dimensional profile of the initial polygon mesh; resizing the polygon mesh a predetermined amount along a normal to the three-dimensional profile of the initial polygon mesh, the resized polygon mesh (406, 406') having a three-dimensional profile being larger than or smaller than the three-dimensional profile of the initial polygon mesh; if the three-dimensional profile of the resized polygon mesh is larger than the three-dimensional profile of the initial polygon mesh, forming the occludee mesh by adjusting the three-dimensional profile of the resized polygon mesh using a polygon optimization process, wherein the occludee mesh encloses a predetermined majority of the three-dimensional profile for the initial polygon mesh, wherein the occludee mesh comprises fewer polygons than the initial polygon mesh, and using the occludee mesh to determine polygon visibility within a scene to be displayed; and if the three-dimensional profile of the resized polygon mesh is smaller than the three-dimensional profile of the initial polygon mesh, forming the occluder mesh by adjusting the three-dimensional profile of the resized polygon mesh using a polygon optimization process, wherein a predetermined majority of the occluder mesh is enclosed by the three-dimensional profile for the initial polygon mesh, wherein the occluder mesh comprises fewer polygons than the initial polygon mesh, and using the occluder mesh to determine polygon visibility within a scene to be displayed.