Abstract: Methods are provided for solid free-form fabrication of an article without using a slice stack file. These apply ray casting a number of times to an electronic representation of the article to create data objects for use directly as printing instructions or which are convertible into printing instructions. The data objects may be utilized as they is generated or after they are created for a portion or all of the article. After utilization, the data objects may be discarded or stored for later use. Layer-specific layer thickness and other-direction resolution parameters may be input and utilized in selecting the number of rays to be cast, their origination points, and their directions, thus permitting controllable variation in detail precision in any direction. Error diffusion techniques may be used to improve fabricated part integrity. Improved intermachine portability is provided. Method, system, code, and media claims are included.

Abstract: An exhaust gas purification system (1) performing regeneration control in a rich condition by using control of an intake system for reducing the quantity of intake air together with control of a fuel system for increasing fuel injection amount into a cylinder, wherein the timing (Tn) for injection fuel into the cylinder is varied in response to the continuous variation (?n) of air fuel ratio in the cylinder during the switching intervals (t1,t2) between lean condition and rich condition at the time of regeneration control of NOx purification catalyst (12). During a period of transition to rich condition or lean condition, misfiring, combustion noise, torque variation, deterioration in drivability, and the like, due to undue advance angle or lag angle in the timing for injecting fuel into the cylinder can thereby be prevented.