how to display Sagittal plane、Coronal plane、transverse plane of a 3d stl file, or PolyData file.
Have you checked out the VTK examples? What was the closest example that you have found? Do you have any specific question about it?
If you want to learn how to do this from scratch then read through all the VTK examples. There are examples that demonstrate how to do each part and you can put together the implementation by combining these pieces.
If you don’t want to spend time with learning and developing these low-level features then you can customize and extend 3D Slicer or MITK to do this. They are developed exactly for the purpose of creating high-quality medical applications with a very little effort. Surgical planning and guidance applications are particularly easy to implement in 3D Slicer, due to the many readily available reusable and configurable components.