A computer aided design system ascertains the clear view area of a transparency in light of head orientation and refractive properties of the transparency. Since a sampling function of finite supports differentiable once or more times over the whole range. In certain examples, a resize tool that operates within a host operating system of a host server dynamically resizes andor aligns one or more VMDK partitions of a powered-down virtual machine. The method and apparatus of this invention allow multiple parallel walking-beam conveyors to feed sand molds to a single junction for transfer to a metal pouring station.