Hi Peter:
Would you be willing to share some Geographic coordinates for this project so we can see what the existing terrain involves ?
Assuming output for FSX/P3D, position a canal 3D model
bottom base plane at Sketchup's Origin of Axes; this would allow it to be placed via BGLComp with its bottom plane on the ground of the FS2Kx underlying terrain mesh at (
-) 4 Meters AGL.
If you remove the canal 3D model bottom Face, terrain Hydro polys and a Water Class 'color' texture may be added via custom photo-real or land class polygon methods, so that actual FS water shows on the underlying terrain mesh surface.
If one makes a FS2Kx terrain mesh quad grid "canal", it will alias / 'morph' via LOD-switching as a function of user A/C camera distance from the 3D object,
regardless of FSX/P3D
*.CFG file mesh resolution and TMVL settings used, (even if the 3D object is precisely aligned on FS' N-S, E-W world grid).
Thus, one must "dig a ditch" into underlying terrain mesh via a CVX vector "sloped flatten"; one's canal 3D model is placed (via BGLComp) in that "ditch".
One may use 3D model terrain 'skirts' to cover up "ditch" edges of nearby underlying terrain quads.
NOTE:
A textured terrain skirt may not change with seasons unless the MDL is made as a (non-flat) G-Poly or SimObject with conditional texture display.
After making your 3D model of the canal and its sloped sides, make a copy of it scaled slightly larger
without the terrain skirts over the edges.
In Sketchup, manually Geo-locate that larger scaled 3D model of the canal and its sloped sides at its intended position / N-S-E-W orientation in FS2Kx.
Export that larger scaled 3D model of the canal and its sloped sides from Sketchup as a Google Earth
*.KMZ file.
Import that larger, scaled and copied 3D model
*.KMZ file into Arno's MCX.
In MCX, export that copied larger, scaled and 3D model as a "
FSX Sloped Flatten" CVX vector BGL; then test it in FSX / P3D.
GaryGB