mesh lab is a 3D mesh processing software that is oriented to the management and processing of this type of large and unstructured meshes. It includes a complete repertoire of tools with which to edit your designs, repair, inspect, render, and convert.
Furthermore, MeshLab is a portable tool, open source, and extensible. With it, it will help you process the typical models that are usually large and that arise from, for example, some 3D scans. For example, you could scale a 3D design and adjust it to your measurements and then print it with your 3D printer in the appropriate size (scale), etc.
MeshLab is undoubtedly a great editor / fixer of STL files, but it is also compatible with other file formats. For example, you can work with PLY, OFF, OBJ, 3DS, COLLADA, and PTX (in addition to STL, which I already mentioned, of course). All of them can be read by him. While to write and store your projects, it supports STL, PLY, OFF, OBJ, 3DS, COLLADA, VMRL and DXF. Therefore, you will not have too much problem in terms of compatibility.
You already know that .STL (STereoLithography) is a format that can be read and edited by Meshlab, and which is one of the most popular if you work with 3D designs, since it is accepted by many models of 3D printers. Basically it is a simplified version of a CAD, with less amount of information and with a final geometry synthesized, summarized, optimized, and reduced to the minimum possible.
That is to say, things that do not interest would disappear, such as the texture of the figure, the internal structure, the colors of the surface finish, information on the physical properties of the material, etc. Only what really matters for these 3D printing cases remains: the shape.
More information and download Meshlab - Official Web site