Got it running once I changed Thread *tp = pt[2] to Thread *tp = pt[0] It ran for a while (which had not hapened before!) then got Floating point error.
2 is the Phase ID in the Phase Interactions GUI but since that phase is the primary phase 0 seems to work.
Since the reaction is contained in the UDF. Should the Reaction under Properties in the Material (for Phase 1 and Phase 2) be set to none or finite-rate.
You are navigating away from the AIS Discovery experience