Question can map 3d convert directly between NGVD29 and NAVD88? If so, where can I find the reference for this procedure? If not is there any documentation on map 3d not being able to do this.
I don't belive you can. I'd probably suggest taking points and running them through "vertcon" from the NGS Geodetic Toolbox first before bringing into either C3D or Map3D.
I could be wrong, but I don't remember seeing it done before.
Think of it as "Map2.5D" as the literature only talks about 2D Coordinate transformations....