diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 3228d8db6..8c3a3b622 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -207,7 +207,7 @@ J2_plasticBehavior:
   stage: fortran
   script:
     - module load $IntelMarc $HDF5Marc $MSC
-    - J2_plasticBehavior/test.py
+    - MSC_VERSION=2020 J2_plasticBehavior/test.py
   except:
     - master
     - release
diff --git a/installation/mods_MarcMentat/2020/Mentat_bin/submit4 b/installation/mods_MarcMentat/2020/Mentat_bin/submit4
index 55e3bcf03..09efd16bb 100644
--- a/installation/mods_MarcMentat/2020/Mentat_bin/submit4
+++ b/installation/mods_MarcMentat/2020/Mentat_bin/submit4
@@ -4,7 +4,7 @@
 # Normal exit status is 0.
 #
 
-DIR=%INSTALLDIR%/marc%VERSION%
+DIR=%INSTALLDIR%/marc2020
 
 if test $MARCDIR1
 then
diff --git a/installation/mods_MarcMentat/2020/Mentat_bin/submit5 b/installation/mods_MarcMentat/2020/Mentat_bin/submit5
index 8699cf076..d7cf96c68 100644
--- a/installation/mods_MarcMentat/2020/Mentat_bin/submit5
+++ b/installation/mods_MarcMentat/2020/Mentat_bin/submit5
@@ -4,7 +4,7 @@
 # Normal exit status is 0.
 #
 
-DIR=%INSTALLDIR%/marc%VERSION%
+DIR=%INSTALLDIR%/marc2020
 
 if test $MARCDIR1
 then
diff --git a/installation/mods_MarcMentat/2020/Mentat_bin/submit6 b/installation/mods_MarcMentat/2020/Mentat_bin/submit6
index a0179482f..f672ea667 100644
--- a/installation/mods_MarcMentat/2020/Mentat_bin/submit6
+++ b/installation/mods_MarcMentat/2020/Mentat_bin/submit6
@@ -4,7 +4,7 @@
 # Normal exit status is 0.
 #
 
-DIR=%INSTALLDIR%/marc%VERSION%
+DIR=%INSTALLDIR%/marc2020
 
 if test $MARCDIR1
 then
diff --git a/installation/mods_MarcMentat/apply_DAMASK_modifications.py b/installation/mods_MarcMentat/apply_DAMASK_modifications.py
index 1cd93c47c..5b6b7a2ce 100755
--- a/installation/mods_MarcMentat/apply_DAMASK_modifications.py
+++ b/installation/mods_MarcMentat/apply_DAMASK_modifications.py
@@ -5,23 +5,36 @@ import glob
 import argparse
 from pathlib import Path
 
-msc_version = os.environ['MSC_VERSION']
-msc_root    = Path(os.environ['MSC_ROOT'])
-damask_root = Path(os.environ['DAMASK_ROOT'])
+import damask
 
 parser = argparse.ArgumentParser(
-     description='Apply DAMASK modification to MSC.Marc/Mentat',
-     epilog = f'MSC_ROOT={msc_root} and MSC_VERSION={msc_version} (from {damask_root}/env/CONFIG)')
+                  description='Apply DAMASK modification to MSC.Marc/Mentat',
+                  prog = Path(__file__).name,
+                  formatter_class=argparse.ArgumentDefaultsHelpFormatter)
+
 parser.add_argument('--editor', dest='editor', metavar='string', default='vi',
                     help='Name of the editor for MSC.Mentat (executable)')
+parser.add_argument('--msc-root', dest='msc_root', metavar='string',
+                    default=damask.solver._marc._msc_root,
+                    help='MSC.Marc/Mentat root directory')
+parser.add_argument('--msc-version', dest='msc_version', metavar='string',
+                    default=damask.solver._marc._msc_version,
+                    help='MSC.Marc/Mentat version')
+parser.add_argument('--damask-root', dest='damask_root', type=float, metavar = 'float',
+                    default=damask.solver._marc._damask_root,
+                    help='DAMASK root directory')
 
 
+args = parser.parse_args()
+msc_root    = Path(args.msc_root)
+damask_root = Path(args.damask_root)
+msc_version = args.msc_version
+
 def copy_and_replace(in_file,dst):
     with open(in_file) as f:
         content = f.read()
     content = content.replace('%INSTALLDIR%',str(msc_root))
-    content = content.replace('%VERSION%', msc_version)
-    content = content.replace('%EDITOR%', parser.parse_args().editor)
+    content = content.replace('%EDITOR%', args.editor)
     with open(dst/Path(in_file).name,'w') as f:
         f.write(content)
 
diff --git a/python/damask/solver/_marc.py b/python/damask/solver/_marc.py
index a6707efd9..b09394e67 100644
--- a/python/damask/solver/_marc.py
+++ b/python/damask/solver/_marc.py
@@ -1,16 +1,16 @@
 import subprocess
 import shlex
 import re
-import os
 from pathlib import Path
 
-_default_version='2020'
-_default_path='/opt/msc'
+_msc_version = 2020
+_msc_root = '/opt/msc'
+_damask_root = str(Path(__file__).parents[3])
 
 class Marc:
     """Wrapper to run DAMASK with MSCMarc."""
 
-    def __init__(self,version=os.environ.get('MSC_VERSION',_default_version)):
+    def __init__(self,msc_version=_msc_version,msc_root=_msc_root,damask_root=_damask_root):
         """
         Create a Marc solver object.
 
@@ -20,12 +20,14 @@ class Marc:
             Marc version
 
         """
-        self.version = version
+        self.msc_version = msc_version
+        self.msc_root    = Path(msc_root)
+        self.damask_root = Path(damask_root)
 
     @property
     def library_path(self):
 
-        path_lib = Path(f'{os.environ.get("MSC_ROOT",_default_path)}/mentat{self.version}/shlib/linux64')
+        path_lib = self.msc_root/f'mentat{self.msc_version}/shlib/linux64'
         if not path_lib.is_dir():
             raise FileNotFoundError(f'library path "{path_lib}" not found')
 
@@ -35,7 +37,7 @@ class Marc:
     @property
     def tools_path(self):
 
-        path_tools = Path(f'{os.environ.get("MSC_ROOT",_default_path)}/marc{self.version}/tools')
+        path_tools = self.msc_root/f'marc{self.msc_version}/tools'
         if not path_tools.is_dir():
             raise FileNotFoundError(f'tools path "{path_tools}" not found')
 
@@ -46,7 +48,7 @@ class Marc:
                    compile      = False,
                    optimization = ''):
 
-        usersub = Path(os.environ['DAMASK_ROOT'])/'src/DAMASK_Marc'
+        usersub = self.damask_root/'src/DAMASK_Marc'
         usersub = usersub.parent/(usersub.name + ('.f90' if compile else '.marc'))
         if not usersub.is_file():
             raise FileNotFoundError(f'subroutine ({"source" if compile else "binary"}) "{usersub}" not found')