Select objects in Maya and populate them into an interactive panel for batch USD export to separate files with clear customisable settings.
The UI promotes standardisation of export settings through the use of user defined presets which are sharable as a file.

How to Use it:

Select targets for export:

Select a list of each of the asset's you want to export to separate files. Each item in your selection will be used as the root of a file.
Then run the tool by clicking the button on your shelf.

You can adjust what is acted on in your selection without removing the entries from the list using the "Enable All" and "Disable All" buttons, or the "Enable Selected" and "Disable Selected" actions which area available when you right click in the graph with a selection of one or more items.
The "Remove" action in the right click menu will remove the entry from the list entirely. To add it or anything else back in, you can select what you want and then use the "Add Selection" Button to add every item you currently have selected in your viewport to the list.
To scrap your current list and include only what you have selected, use the "Refresh Selection" button.

You can automatically collect the list of all skinned mesh and add them to your graph using the "Scan for Skinned Mesh" action in the "Functions" menu. After doing this, there might be too many separate pieces for the same asset. You can combine them into one entry by selecting the list of them, right clicking, and using the menu action "Merge to Common Ancestor".

Choose export settings:

Choose your "Frame range Source" which is where it will collect an assumed frame range from.

The options include:

• Playback Bar: Range
• Playback Bar: Full Range
• Render Settings
• Keyframes

The "keyframes" option will recurse through all descendants of the chosen root to be exported and determine the overall first and last frame.
This can allow you to avoid unnecessary caching of frames after and before those necessary in camera.

You can then "override" the value in the frame range for each separate asset.
Do this by double clicking in the Frame Range column and typing the range you want in the form "start_frame:end_frame". Use a ":" between the two.
You can also use negative frames: "-10:20"
or single frames "25". By typing in just the number, it will be converted to "25:25" automatically.

Customise the "Export Flags" and other USD settings to your preference. This includes the "Frame Stride" and "Frame Relative Sample" settings which are able to be set per export in the graph.
You can get a reminder of the intended notation for the frame relative sample by seeing the tooltip when hovering over the graph title.

Settings that are changed from the default for the current preset will be marked in bold and with blue text.

Confirm the export directory:

Under the "Export Path" group you will find the path your files will be exported to. You can change it by selecting a new path in the file manager that will open when you click the file icon to the right.
You can choose to include the current maya scene name in the cache file name with the "Include Scene Name" checkbox. This can help prevent mix ups when the same asset is exported from different shots or scenes within the same Maya Project.
Use the "Version Up" checkbox to increment the version attached to a cache. Leaving it unchecked will cause an overwrite of the existing version.

Custom File names:
You can take full control over the output file name of an export by double clicking in the "File Name"  column.
Hover over a file name entry to see a tooltip exposing what the full export path is expected to be.

Save a Preset:

Once you have customised some settings, you may want to save a preset using the options in the hamburger menu to the right of the "Preset" selection box.

• Overwrite: Will overwrite the currently selected preset with your current settings.
• Save As: Will open a pop-up allowing you to give your new preset a name.
• Re-name: Will open a pop-up allowing you to give your current preset a new name.
• Delete: Will remove the preset from the selection box and delete the file storing its data on disk.

The presets are stored on a per project basis inside your project file in "your_maya_Project\data\alembic_exporter_settings".You can share or re-use them by simply copying these json files into the same directory in any other Maya project directory.

Export:

Once you are ready, you can finish the operation by clicking the self explanatory "Export" or "Export and Close" buttons.
This will show you a pop-up to display the progress through your list of export tasks.
Once your first export is finished, you may want to view the files on disk. You can get to them quickly using the "Open Output Dir" button on the bottom right

Extras:

You can dock the USD Export UI in Maya.

Notice the icon to the left of each entry. This will denote the recognised object type and includes support for group, mesh, joint. nurbsCurve, nurbsSurface, locator, camera, and light.

If you double click on an item in the "Maya Item" shelf, you can type in an alternative target to be cached out. If you try change it to a path that does not exist, the suggestion will be ignored.

You can remove all user overrides (denoted by blue text) made in the graph at once using the "Clear All User Overrides" action in the "Functions" menu.

Installation:

Open Maya and view the shelf that you want to add the tool to.

Drag and drop the "usd_export.py" file into your Maya session.

The tool will appear on your current shelf.

Other Links:

See it in action: Youtube - Easy USD Exporter for Maya