Hello Ben,
Thank you for posting your question in Bentley Forum.
Export to Native lets you export selected civil geometry elements into one of the following cogo databases: MX FIL files, InRoads ALG files, or GEOPAK GPK files.
This Export to Native functionality is feature-based in that the option to export to native must be set to true or false for each particular feature.
This option controls whether Civil Geometry is exported to the native database automatically or not. When set to Use Feature Setting, any civil geometry elements will exported to the native database when stored with a feature that has the Export to Native option set to true. When set to Manual, Civil Geometry elements can only be exported to the native database via a manual export, regardless of whether the feature being used allows for it or not.
In MXRoad, first we create a model in MXRoad and select your new created model in Feature Definition Toolbox, then after select your geometry string and hit export to Native. This should export to native.
Note: Make sure before exporting you should have feature definition assigned to your geometry string.
In addition to this, please refer the below link for your reference.
communities.bentley.com/.../17174.failed-to-persist-message-when-exporting-to-native
Could you please let us know the native project you are working ?
Regards,
Purva Lakde