Report painter by SAP is one of the most commonly used tool for defining reports in FICO module. Every single controlling reports (Cost center accounting, internal profit and orders center accounting) was ceated using report painter. With Report Painter we can define reports quickly and easily across columns and rows. You need standard reports delivered by SAP as a base, copy them and do minor modifications, to be able to suit your requirement.
Here is a simple how to step by step guide with screenshots on working with Report Painter.