Up to this point I have had the design lead for the Normandy terrain. The terrain is very much still an ALPHA as we have been struggling to accurately depict terrain elevations and
rivers within the limitations of the graphics engine before moving on to field/object placement. All object/field placements in the alpha version are placeholders and do not represent the intended field placements or layouts.
My objective is to provide a 1:1 depiction of the area over which the Normandy air campaign was fought from end-Feb to late-Aug/early-Sep 44. The air battle was fought widely across NW Europe, well beyond the bounds of Normandy proper. After careful consideration of historic airfield locations and air operations, I selected the area in the image below.
Geographically it is a trapezoidal area bounded 51.38N-47.12N and 002W-00430E. For Warbirds use, the area depicted must be a square, so the east-west dimensions are stretched out in the north and compressed in the south. As a result the in game distance from Bournemouth to Antwerp is about 7sm farther than in RL. Not perfect, but close enough.
One of the things I have least liked about many of the Warbirds terrains is the exaggerated vertical scale with over sized rivers at the bottom of massive gorges (esp Europe and ETO). The vertical exaggeration was a necessary evil in older version of WBs to combat terrain "flicker" when elevations near sea level were rendered. This problem was corrected in Warbirds AG, albeit introducing a few other challenges.
My intent is to reproduce the elevations of NW Europe and its river systems as accurately as possible. A significant challenge in that quest (feels the Grail) is overcoming the limitations of the WB graphic engine. Two aspects of this make the accurate depiction of rivers difficult:
1. The game engine only depicts "water" at 0 ft elevation. If you are trying to depict a sea or ocean, no worries. However, as we recall from grade school geography, rivers are usually above sea level and flow down to it. To get the game engine to depict "water" where RL rivers are located the elevations of the courses of the rivers need to be cut down from their RL elevations to some height below 0 ft. Unless the adjacent slopes are smoothed out in the elevation data, the result can be a river at the bottom of a steep gorge. Good for the Grand Canyon or Fraser Rivers, very bad for the relatively gentle banks of the Loire, Seine, Somme or numerous canals.
2. Regardless of the size of the area depicted in a terrain, the game engine is limited in the number of horizontal elevation "pixels" or data points it can use (typically a square matrix 2048 x 2048 data points across). In tiny terrains (e.g. Belgium at 12x12 sm) the pixels are close together (about 33 ft apart in-game) and changes in elevation slopes can be accurately rendered (lots of nooks and crannies in hillsides and smooth, curving rivers and coastlines). Given the expanse of the Normandy terrain (~294x294 sm), the in-game elevation pixels are about 750 ft apart. Given most of the RL rivers and waterways of NW Europe are considerably narrower than 250ft (let alone 750ft), it is impossible to render them accurately. They usually end up wider than in real life and suffer from ugly pixilation effects (e.g. land bridges). Trying to fix them is a PITA requiring trial-by-error pixel by pixel adjustments to the height field.
Next post on what infrastructure we are trying to depict once the elevation model is sorted.
jabo
