BUG
Converting 3D CAD curve entities to geodatabase features does not produce true curve features.
Neither ArcToolbox 'CAD to Geodatabase' tool nor the 'Export Data' command in ArcMap supports the conversion of 3D CAD entities (entities with z values) to geodatabase true curve features. Instead, the 3D CAD curve entities will translate into tessellated geodatabase line and polygon features.
There is no workaround for this known limitation.
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