Weld simulation provides an opportunity to anticipate problems of welding distortion, which affect fabrication cost, and residual stresses which affect fatigue life. A key part of advanced manufacturing, it is used extensively in the heavy equipment and nuclear industries. Although it is possible to perform weld simulation by transient thermal finite element analysis, the concentrated nature of weld heat makes it tedious and time-consuming to mesh the welds adequately. Instead, singular asymptotic temperature distribution functions can be used to model heating and cooling within a concise iterative technique. Weld passes are specified in the final structural mesh by a convenient Graphical User Interface (GUI), while an efficient Virtual Element Detection (VED) scheme keeps track of which weld pass elements are structurally active at a particular time. Using semi-automatic weld pass meshing for extra productivity, the GUI allows the user to examine the effect of weld pass number, sequence and direction. Since weld simulation involves a long sequence of non-linear structural analyses, it is essential to take advantage of multi-core supercomputing. Both VFT and the public-domain structural solver WARP3D are optimized for multi-core execution and are available as economical AweSim apps at the Ohio Supercomputer Center (OSC). VFT supports a wide range of molten material laws, including Chaboche and Leblond within the framework of a user routine. VFT is indeed available on the OSC system on an ‘on demand’ basis for very low cost. These analyses can be performed on the supercomputer on multiple processors very easily. The technique is illustrated with examples including application to rollover-cage structural framework welds.