Abstract: We propose a digital watermarking algorithm for meeting the needs of CAD and other engineering applications. By the approach the watermark information is embedded into the triangle mesh based on global L_∞ error control. It embeds watermark in the vertexes' coordinates by establishing multi-resolution meshes of the original model, and controls global error by the local geometrical features of the model. Because the watermark is embedded redundantly in the whole band of the model, the approach is robust against various attacks. Experiments show that this scheme can control the global error within certain threshold, and it is robust against attacks such as mesh simplification, model cropping and random noise, etc.