Using ModelSim-Altera with Altera designs

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And if the Altera libraries are already come pre-compiled, how do you "point" to them? Is there a ModelSim setup file that is read by vsim? Or would I need to use vmap and vlib?

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Here are a few lines from scripts I used 3 years ago. This might need adjusting. The default directory structure has changed since then.

set ModelSim_OEM_install $::env(MODEL_TECH);         #  Setting ModelSim_OEM_install to location of ModelSim that is executing this
set ModelSim_OEM_install $ModelSim_OEM_install/..;   #  script.  The ".." is to get above the win32aloem directory.
vlib lpm
vlib altera_mf
vmap altera_mf $ModelSim_OEM_install/altera/vhdl/altera_mf;
vmap lpm $ModelSim_OEM_install/altera/vhdl/220model;