How does external data map temperatures to nodes outside the source domain?
By default we use a distance based average scheme for the outside nodes. At R13 it was hard coded to 3 point. The temperature of the three closest nodes is used in a weighted average based on the distance to the node. At 14.0 we let the user control the number of "N" closest nodes. (There is also a projection technique. See documentation for specifics.)
There are several features here in 14.0:
1) The ability to create nodal named selections for nodes found outside.
2) More options to control how to handle outside nodes.
3) A distance limit to how far we allow outside nodes be mapped.
4) The Source Value Validation to see the source results overlayed on the mapped results.
For more information
// Mechanical Application User's Guide // Appendices :: 0 // B. Data Transfer Mesh Mapping