The Mesh page of the Object Settings dialog:

Pivot

The object's pivot point is taken into consideration when exporting meshes.

Mesh Settings

• Mesh Name - The name of the exported mesh. If not specified, the object name is used.
• Primitive Type - The type of primitives used to render the mesh.
• Vertex Buffer Usage - The behavior of the vertex buffer.
• Vertex Buffer Usage - Use Shadow - Indicates whether a shadow buffer should be maintained for the vertex buffer.
• Index Buffer Usage - The behavior of the index buffer.
• Index Buffer Usage - Use Shadow - Indicates whether a shadow buffer should be maintained for the index buffer.
• Export Vertex Colors - Indicates whether vertex colors should be exported.
• Generate Edge Lists - Indicates whether edge lists are generated for meshes.
• Remove Duplicate Vertices - Indicates whether duplicate vertices should be removed. Removing duplicate vertices slows down the export process.
• Animate Bounding Volumes - Indicates whether mesh bounding volumes should be calculated using an animated version of the mesh. Enabling this setting slows down the export process.
• Make Bounding Box Cub - Indicates whether the mesh bounding box should be exported as a cube, with each side taken to be the largest of the non-cube version of the bounding box.
• Check for Mesh Instance - Indicates whether the mesh should be checked against other meshes to determine if it is in instance. This setting is ignored if the object is a Submesh or the Check for Mesh Instances setting of the scene mesh settings is disabled.

Normal/Tangent/Binormal Settings

• Generate Normals - Indicates whether normals should be generated and exported.
• Animated Normals - Indicates whether animated normals should be exported for mesh pose and morph animations. Note that this feature is only available in Ogre 1.8 and above, and is incompatible with stencil shadows.
• Generate Tangents - Indicates whether tangents should be generated and exported.
• Binormals - Indicates whether binormals should be generated and exported.
• Split Mirrored - Indicates whether to split vertices when a mirrored tangent space transition is detected.
• Split Rotated - Indicates whether to split vertices when tangent space rotates more than 90 degrees around a vertex.
• Store Parity In W - Indicates whether tangent space parity should be set in the W of a 4-component tangent.

Submeshes/Texture Coordinate Sets

• Customize Submeshes - Indicates whether custom settings should be used. If checking this for the first time, you will also want to press the Refresh button to fill the settings list. Failure to do this will result in the exported mesh having no texture coordinate sets, corresponding to the empty list within the dialog window.
• Submesh/Material - Upon export, meshes are segmented into submeshes based on the different materials applied to the mesh. Each material corresponds to a submesh with its own texture coordinate sets. This setting lets you select which submesh's settings are being edited.
• Submesh Name - The name of the submesh. If empty, a default name will be assigned during export.
• Refresh - Refreshes the texture coordinate sets for the specified submesh. This puts the settings back to their default value.
• Clear - Removes all texture coordinate sets from the specified submesh.
• Move Up - Moves the selected texture coordinate set up in the ordering.
• Move Down - Moves the selected texture coordinate set down in the ordering.
• Remove - Removes the selected texture coordinate set.
• U (1D) - Sets the selected texture coordinate set to have 1D texture coordinates (each texture coordinate will have a U component).
• UV (2D) - Sets the selected texture coordinate set to have 2D texture coordinates (each texture coordinate will have U and V components).
• UVW (3D) - Sets the selected texture coordinate set to have 3D texture coordinates (each texture coordinate will have U, V, and W components).