How to create a Terrain offset Vertically from a Terrain?

Question

For a 3D model that is built from a 3D Boundary Edges Terrain(ex. intersection) and a Surface Temple with Linear Templates on the edges. 
 What is the best way to create the bottom mesh? 
 We can use the 3D break lines generated by the Linear Template. However, when a surface Template is applied to the Terrain there are no 3D lines generated. 
 So we though we could create a vertical offset terrain to use and append the outside break lines. 
 Which begs the question in the subject? 
 Any other suggestions ?

Mark Marnell · Accepted Answer

When you apply the surface template to the terrain, the 3D linear features will be created if you have set the 'Create Linear Features' = TRUE.

Vern Danforth · Answer

Actually, 
 
I have found a couple of ways 
 
1. Using the Terrain Clipping tool, set to external and select the boundary of the original intersection terrain . You can enter a vertical offset. However, this doesn't honor the boundary and the extra triangles have to be trimmed. 
2. Using the copy element tool in Microstation, select the boundary of the original intersection terrain and then use the Keyin dx=,,-.75 
to make a new 3d element. Add this a boundary element to the new offset terrain above.

Vern Danforth · Answer

OK We found that if you select the surface mesh component and choose properties, that you can Create Linear Features to True. Thank you. 
 Does any one know how to set this by project... is it a variable or design file setting?