Design constraints, which express design intent, are one of the pieces of ancillary data that are critical to the success of a custom design. Design constraints aren’t usually contained within layout files or library information, but without these critical data, designs may not meet specifications. Today, most custom design teams manage constraints in ad-hoc, manual fashions. This approach has become a significant limitation to automating custom design, which in turn can limit both design productivity and accuracy. The custom design community is looking to standards efforts to ease the burden of correlating and communicating design constraints throughout the design process.