ISE modelsim仿真报错解决方法

ISE modelsim仿真遇到了这个报错
WARNING: unable to resolve env var in modelsim.ini file entry: $::env(MODEL_TECH)/…/std
WARNING: unable to resolve env var in modelsim.ini file entry: $::env(MODEL_TECH)/…/ieee
WARNING: unable to resolve env var in modelsim.ini file entry: $::env(MODEL_TECH)/…/vital2000
WARNING: unable to resolve env var in modelsim.ini file entry: $::env(MODEL_TECH)/…/verilog
WARNING: unable to resolve env var in modelsim.ini file entry: $::env(MODEL_TECH)/…/std_developerskit
WARNING: unable to resolve env var in modelsim.ini file entry: $::env(MODEL_TECH)/…/synopsys
WARNING: unable to resolve env var in modelsim.ini file entry: $::env(MODEL_TECH)/…/modelsim_lib
WARNING: unable to resolve env var in modelsim.ini file entry: $::env(MODEL_TECH)/…/sv_std
WARNING: unable to resolve env var in modelsim.ini file entry: $::env(MODEL_TECH)/…/avm
WARNING: unable to resolve env var in modelsim.ini file entry: $::env(MODEL_TECH)/…/ovm-2.1.2
WARNING: unable to resolve env var in modelsim.ini file entry: $::env(MODEL_TECH)/…/uvm-1.1c
WARNING: unable to resolve env var in modelsim.ini file entry: $::env(MODEL_TECH)/…/upf_lib
WARNING: unable to resolve env var in modelsim.ini file entry: $::env(MODEL_TECH)/…/pa_lib
WARNING: unable to resolve env var in modelsim.ini file entry: $::env(MODEL_TECH)/…/floatfixlib
WARNING: unable to resolve env var in modelsim.ini file entry: $::env(MODEL_TECH)/…/mc2_lib
WARNING: unable to resolve env var in modelsim.ini file entry: $::env(MODEL_TECH)/…
WARNING: unable to resolve env var in modelsim.ini file entry: $::env(MODEL_TECH)/libsm.sl
WARNING: unable to resolve env var in modelsim.ini file entry: $::env(MODEL_TECH)/libhm.sl

是因为没有MODEL_TECH这个环境变量，解决方法是在环境变量中添加modelsim的安装路径，如D:\Softwares\modelsim

参考：https://forums.xilinx.com/t5/Welcome-Join/model-sim-student-edition/td-p/280722