Simulations need high quality mesh representations as input which are often manually prepared. The fully automatic mesh preprocessor software MERGE avoids this time consuming task. The software CAD or STL data as input, repairs invalid meshes and merges the input objects together. Small gaps between the input objects are automatically closed. The output surface mesh can be supplied in two different flavors, either as a mesh that minimizes the number of elements or as a mesh consisting of high quality triangles, ready for 3D meshing. A closed and connected surface mesh of an entire car body can be prepared overnight in a fully automatic manner.