This script installs all the 32 bit library dependencies of modelsim and also compiles freetype.

configure_modelsim.sh

#!/bin/bash

ALTERA_PATH=~/altera/13.1/

sudo dpkg --add-architecture i386
sudo apt-get update
sudo apt-get install gcc-multilib g++-multilib \
lib32z1 lib32stdc++6 lib32gcc1 \
expat:i386 fontconfig:i386 libfreetype6:i386 libexpat1:i386 libc6:i386 libgtk-3-0:i386 \
libcanberra0:i386 libpng12-0:i386 libice6:i386 libsm6:i386 libncurses5:i386 zlib1g:i386 \
libx11-6:i386 libxau6:i386 libxdmcp6:i386 libxext6:i386 libxft2:i386 libxrender1:i386 \
libxt6:i386 libxtst6:i386
cd /tmp
wget http://download.savannah.gnu.org/releases/freetype/freetype-2.4.12.tar.bz2
tar -xjvf freetype-2.4.12.tar.bz2
cd freetype-2.4.12
./configure --build=i686-pc-linux-gnu "CFLAGS=-m32" "CXXFLAGS=-m32" "LDFLAGS=-m32"
make -j8
mkdir $(ALTERA_PATH)/modelsim_ase/lib32
sudo cp objs/.libs/libfreetype.so* $(ALTERA_PATH)/modelsim_ase/lib32

#this file is usually read-only, make it writeable
chmod 755 $(ALTERA_PATH)/modelsim_ase/vco
echo -e "Add the following line \n\texport LD_LIBRARY_PATH=\${dir}/lib32\nafter this line\n\tdir=\`dirname \$arg0\`\nin the file ${ALTERA_PATH}modelsim_ase/vco"

modelsim_32bit_deps.sh

sudo dpkg --add-architecture i386
sudo apt-get update
sudo apt-get install wine
sudo apt-get install gcc-multilib g++-multilib lib32z1 lib32stdc++6 lib32gcc1 \
expat:i386 fontconfig:i386 libfreetype6:i386 libexpat1:i386 libc6:i386 libgtk-3-0:i386 \
libcanberra0:i386 libpng12-0:i386 libice6:i386 libsm6:i386 libncurses5:i386 zlib1g:i386 \
libx11-6:i386 libxau6:i386 libxdmcp6:i386 libxext6:i386 libxft2:i386 libxrender1:i386 \
libxt6:i386 libxtst6:i386

modelsim_crack.sh

mkdir -p /tmp/modelsim_crack
tar -xvzf ModelSim_linux_crack.tar.gz -C /tmp/modelsim_crack
cd /tmp/modelsim_crack/
./sfk6 rep -yes -pat -bin /5589E557565381ECD00000008B5508/31C0C357565381ECD00000008B5508/ -dir ~/modelsim/
sudo ./MentorKG.exe -i license.src -o ~/modelsim/license.dat -hn -pkg ~/modelsim/modeltech/linux_x86_64/mgls/lib/mgc.pkginfo

modelsim_custom_libfreetype.sh

cd /tmp
wget http://download.savannah.gnu.org/releases/freetype/freetype-2.4.12.tar.bz2
tar -xjvf freetype-2.4.12.tar.bz2
cd freetype-2.4.12
./configure --build=i686-pc-linux-gnu "CFLAGS=-m32" "CXXFLAGS=-m32" "LDFLAGS=-m32"
make -j8

mkdir ~/modelsim/modeltech/lib32
sudo cp objs/.libs/libfreetype.so* ~/modelsim/modeltech/lib32
 
#this file is usually read-only, make it writeable
chmod 755 ~/modelsim/modeltech/vco
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/home/teja/modelsim/modeltech/lib32/
echo -e "Add the following line \n\texport LD_LIBRARY_PATH=\${dir}/lib32\nafter this line\n\tdir=\`dirname \$arg0\`\nin the file ~/modelsim/modeltech/lib32/vco"

modelsim_env.sh

export LM_LICENSE_FILE=~/modelsim/license.dat
export PATH=$PATH:/home/teja/modelsim/modeltech/linux_x86_64/
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/home/teja/modelsim/modeltech/lib32/

You might have trouble with your NIC not being called eth0 (or ethX) as expected by modelsim, which will make it fail to accept your license file. A workaround is described at http://www.itzgeek.com/how-tos/mini-howtos/change-default-network-name-ens33-to-old-eth0-on-ubuntu-16-04.html

For details about what you're disabling, check FreeDesktop on predictable network interfaces

just a big THANK YOU for these scripts, I was really struggling to get ModelSim 10.5b running on Ubuntu 18.04 until I found these