ERROR: Abaqus/Explicit requires isothermal rigid bodies to have a non-zero capacitance unless temperature degrees of freedom are constrained with the *BOUNDARY option. Nodes that are part of an isothermal rigid body do not require capacitance individually, but the rigid body as a whole must possess capacitance unless constraints are used. To remedy this error, either add temperature constraints to the reference nodes with the *BOUNDARY option or add capacitance  using the *HEATCAP option, whichever is appropriate to obtain the desired response. A node set named "ErrNodeIsoThermBodyNoCap"  containing the problematic reference nodes is created to help the  user locate the error and modify the input definition.