Renishaw OMV (on-machine verification) is a verification package for machine tool users requiring powerful inspection software, giving 3D verification against a CAD model. The software is targeted at manufacturers of complex and large parts, such as mould tools, and combines freeform and geometric features. A straightforward point-and-click approach means that the user can see the inspection path as it is generated, and make changes if required. Using Renishaw OMV for inspection allows manufacturers to detect errors earlier and correct them before the parts are removed from the machine tool. The ability to check that the part is reaching specification at various stages of the manufacturing process will save time, reduce the amount of scrapped components and increase confidence. In combination with Renishaw's RENGAGE spindle touch probes, Renishaw OMV provides unrivalled accuracy of part verification on machine tools. Non-lobing, high accuracy RENGAGE probes, such as the MP700 and new OMP400 ultra-compact touch probe, are ideally suited to the 3D inspection routines made possible with Renishaw OMV. Surface data is measured and sent to a PC, where powerful measurement algorithms process the data. Features such as multi-point circles, cylinders, cones, spheres and planes, can now be measured to a high degree of accuracy, and powerful ‘best fit’ algorithms match groups of measured data to the model, reducing the deviations and errors, by removing alignment and datum constraints.