Just built panda from cvs (on windows).
And curious what libmayapview.mll and libmayasavepview.mll maya plugins found in $INSTALL_DIR/lib for?
These are plug-ins that enable you to convert and view a Maya model while you are working on it, so you can see how it will look in Panda. It’s just an interactive viewer; it doesn’t save out an egg file in the same way that the 3DSMax plug-in works.
To use them, first ensure that your $INSTALL_DIR/lib directory is on your PATH and your MAYA_PLUG_IN_PATH before you start Maya, and when you open the plug-in manager in Maya it should offer you your choice of the two plug-ins. You can choose either one, but not both at the same time (since they define the same entry point–they each create a new Maya function called pview()).
The difference between the two is that libmayapview.mll is fully integrated with Maya and runs within the Maya process. That means it doesn’t require saving the file to disk first (although that’s probably a good idea in the case of a crash), and it knows what parts of the file you have selected. If you have any pieces selected, it views only those pieces within pview; otherwise, it views the whole file. It also pauses your Maya environment while the pview window is open.
On the other hand, libmayasavepview.mll runs pview.exe in a separate process. It works by quietly saving the file when you run it, and then it fires up a pview command to view it. Since it runs in its own process, it doesn’t pause Maya, and it’s a little less likely to bring Maya down should something go wrong. It also cannot know what parts you have selected, so it always views the whole file.
That’s great! Thank you.
Hey there. I realize this is REALLY old, and things perhaps have changed. However, I’ve only ever used the libmayapview.mll file, never having even loaded the libmayasavepview.mll in any of my Maya installation, from 2012 to 2016. For me, (using the MayaPandaTools.mel interface anyhow) The libmayapview.mll seems to perform exactly how you described the libmayasavepview.mll is supposed to. 
Currently, using the interface as I mentioned, Maya will always save out a egg file before running the pview.exe command on it. As well, when running the menu option to view a file, it of course brings up the dialog to choose an egg file. I know I’ve done some modifications to this tool, however most all the original base coding is still entact as it’s been. I mostly did mods to the GUI and added some commands.
~Sean~