diff --git a/samples/qt/FuncDemo/env.sh b/samples/qt/FuncDemo/env.sh
index f081139a1a..616847c074 100644
--- a/samples/qt/FuncDemo/env.sh
+++ b/samples/qt/FuncDemo/env.sh
@@ -3,19 +3,24 @@
 export aSamplePath="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
 
 if [ -e "custom.sh" ]; then
-   source "custom.sh";
+  source "custom.sh" $*;
 fi
 
 if [ -e "${aSamplePath}/../../../env.sh" ]; then
-   source "${aSamplePath}/../../../env.sh";
+  source "${aSamplePath}/../../../env.sh" $*;
 fi
 
-if test "${QTDIR}" == ""; then
-   echo "Environment variable \"QTDIR\" not defined. Define it in \"custom.sh\" script."
-   exit 1
+if [ "${QTDIR}" != "" ]; then
+  export PATH=${QTDIR}/bin:${PATH}
+else
+  aQMakePath=`which qmake`
+  echo "Environment variable \"QTDIR\" not defined.. Define it in \"custom.sh\" script."
+  if [ -x "$aQMakePath" ]; then
+    echo "qmake from PATH will be used instead."
+  else
+    exit 1
+  fi
 fi
 
 host=`uname -s`
 export STATION=$host
-
-export PATH=${QTDIR}/bin:${PATH}
diff --git a/samples/qt/FuncDemo/make.sh b/samples/qt/FuncDemo/make.sh
index 8fc47f63c9..1b771ffbe0 100644
--- a/samples/qt/FuncDemo/make.sh
+++ b/samples/qt/FuncDemo/make.sh
@@ -1,13 +1,14 @@
 #!/bin/bash
 
 export aSamplePath="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
-if [ -e "${aSamplePath}/env.sh" ]; then source "${aSamplePath}/env.sh"; fi
+if [ -e "${aSamplePath}/env.sh" ]; then source "${aSamplePath}/env.sh" $*; fi
 cd $aSamplePath
 qmake FuncDemo.pro
 if [ "$(uname -s)" != "Darwin" ] || [ "$MACOSX_USE_GLX" == "true" ]; then
+  aNbJobs="$(getconf _NPROCESSORS_ONLN)"
   if [ "${CASDEB}" == "d" ]; then
-    make debug
+    make -j $aNbJobs debug
   else
-    make release
+    make -j $aNbJobs release
   fi
 fi
diff --git a/samples/qt/FuncDemo/run.sh b/samples/qt/FuncDemo/run.sh
index 8129d8f69c..9e12027359 100644
--- a/samples/qt/FuncDemo/run.sh
+++ b/samples/qt/FuncDemo/run.sh
@@ -2,7 +2,7 @@
 
 export aSamplePath="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
 
-if [ -e "${aSamplePath}/env.sh" ]; then source "${aSamplePath}/env.sh"; fi
+if [ -e "${aSamplePath}/env.sh" ]; then source "${aSamplePath}/env.sh" $*; fi
 cd $aSamplePath
 
 aSystem=`uname -s`
diff --git a/samples/qt/IESample/env.sh b/samples/qt/IESample/env.sh
index eef770d4ef..66610d7150 100755
--- a/samples/qt/IESample/env.sh
+++ b/samples/qt/IESample/env.sh
@@ -3,20 +3,25 @@
 export aSamplePath="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
 
 if [ -e "custom.sh" ]; then
-   source "custom.sh";
+  source "custom.sh" $*;
 fi
 
 if [ -e "${aSamplePath}/../../../env.sh" ]; then
-   source "${aSamplePath}/../../../env.sh";
+  source "${aSamplePath}/../../../env.sh" $*;
 fi
 
-if test "${QTDIR}" == ""; then
-   echo "Environment variable \"QTDIR\" not defined. Define it in \"custom.sh\" script."
-   exit 1
+if [ "${QTDIR}" != "" ]; then
+  export PATH=${QTDIR}/bin:${PATH}
+else
+  aQMakePath=`which qmake`
+  echo "Environment variable \"QTDIR\" not defined.. Define it in \"custom.sh\" script."
+  if [ -x "$aQMakePath" ]; then
+    echo "qmake from PATH will be used instead."
+  else
+    exit 1
+  fi
 fi
 
 host=`uname -s`
 export STATION=$host
 export RES_DIR=${aSamplePath}/${STATION}/res
-
-export PATH=${QTDIR}/bin:${PATH}
diff --git a/samples/qt/IESample/make.sh b/samples/qt/IESample/make.sh
index ef84e31e77..b6528143f2 100755
--- a/samples/qt/IESample/make.sh
+++ b/samples/qt/IESample/make.sh
@@ -1,13 +1,14 @@
 #!/bin/bash
 
 export aSamplePath="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
-if [ -e "${aSamplePath}/env.sh" ]; then source "${aSamplePath}/env.sh"; fi
+if [ -e "${aSamplePath}/env.sh" ]; then source "${aSamplePath}/env.sh" $*; fi
 cd $aSamplePath
 qmake IESample.pro
 if [ "$(uname -s)" != "Darwin" ] || [ "$MACOSX_USE_GLX" == "true" ]; then
+  aNbJobs="$(getconf _NPROCESSORS_ONLN)"
   if [ "${CASDEB}" == "d" ]; then
-    make debug
+    make -j $aNbJobs debug
   else
-    make release
+    make -j $aNbJobs release
   fi
 fi
diff --git a/samples/qt/IESample/run.sh b/samples/qt/IESample/run.sh
index a9374a3133..29c300b166 100755
--- a/samples/qt/IESample/run.sh
+++ b/samples/qt/IESample/run.sh
@@ -2,7 +2,7 @@
 
 export aSamplePath="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
 
-if [ -e "${aSamplePath}/env.sh" ]; then source "${aSamplePath}/env.sh"; fi
+if [ -e "${aSamplePath}/env.sh" ]; then source "${aSamplePath}/env.sh" $*; fi
 cd $aSamplePath
 
 aSystem=`uname -s`
diff --git a/samples/qt/Tutorial/env.sh b/samples/qt/Tutorial/env.sh
index eef770d4ef..66610d7150 100755
--- a/samples/qt/Tutorial/env.sh
+++ b/samples/qt/Tutorial/env.sh
@@ -3,20 +3,25 @@
 export aSamplePath="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
 
 if [ -e "custom.sh" ]; then
-   source "custom.sh";
+  source "custom.sh" $*;
 fi
 
 if [ -e "${aSamplePath}/../../../env.sh" ]; then
-   source "${aSamplePath}/../../../env.sh";
+  source "${aSamplePath}/../../../env.sh" $*;
 fi
 
-if test "${QTDIR}" == ""; then
-   echo "Environment variable \"QTDIR\" not defined. Define it in \"custom.sh\" script."
-   exit 1
+if [ "${QTDIR}" != "" ]; then
+  export PATH=${QTDIR}/bin:${PATH}
+else
+  aQMakePath=`which qmake`
+  echo "Environment variable \"QTDIR\" not defined.. Define it in \"custom.sh\" script."
+  if [ -x "$aQMakePath" ]; then
+    echo "qmake from PATH will be used instead."
+  else
+    exit 1
+  fi
 fi
 
 host=`uname -s`
 export STATION=$host
 export RES_DIR=${aSamplePath}/${STATION}/res
-
-export PATH=${QTDIR}/bin:${PATH}
diff --git a/samples/qt/Tutorial/make.sh b/samples/qt/Tutorial/make.sh
index 791c414b9a..2a4169279b 100644
--- a/samples/qt/Tutorial/make.sh
+++ b/samples/qt/Tutorial/make.sh
@@ -1,13 +1,14 @@
 #!/bin/bash
 
 export aSamplePath="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
-if [ -e "${aSamplePath}/env.sh" ]; then source "${aSamplePath}/env.sh"; fi
+if [ -e "${aSamplePath}/env.sh" ]; then source "${aSamplePath}/env.sh" $*; fi
 cd $aSamplePath
 qmake Tutorial.pro
 if [ "$(uname -s)" != "Darwin" ] || [ "$MACOSX_USE_GLX" == "true" ]; then
+  aNbJobs="$(getconf _NPROCESSORS_ONLN)"
   if [ "${CASDEB}" == "d" ]; then
-    make debug
+    make -j $aNbJobs debug
   else
-    make release
+    make -j $aNbJobs release
   fi
 fi
diff --git a/samples/qt/Tutorial/run.sh b/samples/qt/Tutorial/run.sh
index c06f3fed5e..d314656906 100755
--- a/samples/qt/Tutorial/run.sh
+++ b/samples/qt/Tutorial/run.sh
@@ -2,7 +2,7 @@
 
 export aSamplePath="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
 
-if [ -e "${aSamplePath}/env.sh" ]; then source "${aSamplePath}/env.sh"; fi
+if [ -e "${aSamplePath}/env.sh" ]; then source "${aSamplePath}/env.sh" $*; fi
 cd $aSamplePath
 
 aSystem=`uname -s`