The paper presents the concept of a real-time seam tracking system for welding automation and the initial design for building a prototype. The ARTIST - Adaptive Real-Time Intelligent Seam Tracker - uses a robot-held, laser based vision system for automation of arc welding processes, and is currently under development at the Applied Research Laboratory of The Pennsylvania State University. The design of ARTIST builds upon the concept of a zero-pass technique where 3D information of the seam geometry is collected and processed for real time guidance and control of the welding torch trailing behind the laser-based vision sensor. This zero-pass concept eliminates the need for pre-programming of the weld path and thus potentially enhances the welding cycle time for small batches. The ARTIST is designed to support multipass arc welding and to handle any tack welds which are encountered during the seam welding operation.