The qmake tool is a program that helps with creating makefiles using the information inside the *.pro files. This simply means, using a very simple syntax (as opposed to more complex syntax in other make systems), qmake generates all the necessary commands for correctly compiling and building an application, and puts all those generated files inside the Build folder.
When a Qt project is built, it first creates a new build folder, which by default, is on the same level as the project folder. In our case, this folder should have a name similar to build-Hello_Qt_OpenCV-Desktop_Qt_5_9_1_*-Debug, where * can be different, depending on the platform, and you can find it in the same folder where your project folder is located. All ...
