Simulation scripts generated for Third party simulators fail if the core container is enabled for a subset of IP (for example, TPG, DDC).
The simulation files for a TPG IP core are not found using Questa or ModelSim:
Export Simulation is trying to find netlist.v, but only a .xcix file exists when core container is enabled.
For a container IP, export simulation will try to find the relative path of the netlist file which has not been generated yet, while an out of context (OOC) run for the IP core is still running.
It defaults to the project.srcs/v_tpg_0/ip path as soon as export simulation is called from "generate target".
Because this is a core container IP, the netlist file does not exist on the disk and the script will fail.
This is expected to be fixed in Vivado 2016.1.
To work around the issue, export simulation after the OOC run has completed.
See (UG835): Tcl command reference guide for export_simulation command usage.