Is there a tool or process where modified cross section graphics in a cross section set can be imported into a surface or even update the pre-existing DTM.
We do not have a tool that can take components from a cross section and update them back to a surface. Components are defined by the features in the DTM so the cross sections create the component between thesefeatures when it is displayed. If you modify any graphics in a cross section, this is merely changing graphics and not updating the surface component because you are not changing the actual breakline features that define the component. If you go to Surface > Features > Component Properties you can select a component and choose the List button on the right to see the list of features that define the component. This is what controls the components so we can’t take a graphic back to a surface.
Even though we can’t take components from a cross section to a surface, you can convert a drawn line in the cross sections to a DTM. You could use this method to create separate triangulated surfaces for the top of the component and bottom of the component and accomplish what you need as an end result.
Please refer to this wiki article for a detailed workflow for generating a surface from graphics in a cross section: