When you run the machineOutput option in export mode, OVF Tool reports the following status sequence:

1

AUTHENTICATION (zero or more)

2

MANIFEST (zero or one)

3

CERTIFICATE (zero or one)

4

PROGRESS (one or more)

5

TARGET_ID (exactly one)

6

RESULT (exactly one)

To use machine mode to download an OVF from vSphere, you run the following command. 

ovftool.exe --machineOutput                                       \
            --I:sourceSessionTicket=<session ticket>              \
            -tt <OVA or OVF>                                      \
            -n=<name>                                             \
            --overwrite (optional)                                \
            --powerOffSource (optional)                           \
            --chunkSize=<value> (optional)                        \
            --compress=<value> (optional)                         \
            vi://<servername>?moref=<type>:<moref-id>             \
            <directory>

The type value is either vim.VirtualMachine or vim.VirtualVApp.

When you specify --machineOutput, OVF Tool monitors STDIN, and cancels the operation if it reads the ABORT\n line in stdin.

For an example, see Output from Running machineOutput in Export Mode.