The only way to show the full displacement (terrain shape) is to compute the shape of the terrain. Using OpenGL or DirectX to display this isn't going to make it faster - it's fundamentally a CPU-bound process. MojoWorld's preview is notorious for innaccuracy since it does not fully compute 2nd or higher order displacements. TG2, on the other hand, fully computes displacements, so it is more accurate, but yes it is slower. When dealing with fine displacements, as is often the case in TG2, this is particularly important. As Reck mentioned turning off Atmosphere and Lighting can help, if you only want to see the terrain for positioning. The preview speed will indeed be improved in the future when multithreading is possible.
- Oshyan