As certain traditional technical and engineering applications become established on the Web, they bring with them information resources that mix text and data with significant technical graphics components. Technical graphics for such applications as aircraft maintenance manuals are characterized by high volume and complexity, stringent fidelity and interoperability constraints, and long life cycle. W3C has two standards for Web based graphics, WebCGM and SVG. WebCGM was specifically standardized for technical applications. SVG has much broader applicability. In a nutshell, the usual formula is "WebCGM for Web-based technical graphics, SVG for graphic arts and creative graphics." Still, the questions continue to arise. why there are two formats, and isn't it possible to use the one for the other application? When one takes a careful and detailed look at the two formats, in the context of the particular requirements of technical illustration, then specific differences emerge. This session will present such a comparison, from both the theoretical, functional perspective, as well a practical real-world (implemenations and interoperability) perspective. The comparison is based on an ongoing study that has been conducted within the CGM Open consortium and the Graphics Working Group of the Air Transport Association.