This is a simple opencascade demo based on oce/6.8.0 community version and in occQt.
First is needed donwload the opencascade srcs, compile and install and download the qt5 development tools using you preferred package manager.
This example use qmake-qt5 to generate Makefile and compile the sources. Is a good practice create a build dir to compile.
$ cd QtOccWidget
$ mkdir build
$ cd build
$ qmake-qt5 ../OccWidget.pro
$ make
$ ./OccWidget