How can I open a file in DVT from Questa?

You can define the following procedure in a tcl script:

set ::env(DVT_HOME) /dvt/installation/location
set ::env(DVT_WORKSPACE_PATH) /dvt/workspace/location

proc dvtEdit { filename {linenumber 1} } {
    set line $linenumber
    if { $line < 1 } {
        set line 1
    }
    exec $::env(DVT_HOME)/bin/dvt_cli.sh openFile $filename -line $line &
}

To make the new procedure available in the Questa tcl command line, add the script path to the MODELSIM_TCL environment variable:

MODELSIM_TCL=tcl_script_path.tcl:$MODELSIM_TCL

To set DVT as the default editor for opening files in Questa, run the following tcl command:

set PrefSource(altEditor) dvtEdit

To revert the settings for the default editor, run the following tcl command:

unset PrefSource(altEditor) dvtEdit