Let's start off with a pretty basic scenario. We have this model, which we've exported from a 3D modeling package, and we would like to use it for our game. The first thing we need to do is convert it to the format that jMonkeyEngine 3 uses internally (.j3o). The recommended format to use is .blend coming from the open source modeling package Blender for which the SDK has extensive support. Another common format is .obj for static models and Ogre-mesh XML files.
We can import a model by performing the following steps:
Go to the File menu and select Import Model.
Next, we need to choose the project we would like to import.
After selecting the actual model to be imported, we get to preview the model and can make sure that all the assets are properly used.
Finally, we select where to place it in the Project Assets folder structure.
The importer converts the model to the internal .j3o format. This is a binary format, which means it becomes nonreadable (compare it with a .obj file, which can be edited in Notepad). The compactness of a binary file is necessary to keep memory consumption low. It becomes impossible to edit externally, though, so keeping the original files organized is a good idea!