Terrain Cracks

[ulf.schroeter]

Problem

 

New terrain shows visible cracks between different tile levels ( coarse=blue, surface=green, patch=red). Border tesselation between levels seems to be ok, but adjacent vertices use different height values. See screenshot for terrain with 2049x2049 grid, 8x8 surfaces, step 10, height 4000 and loads setting 25

 

[frustum]

We can't eliminate cracks between patch and surface level when LOD distance is too close. The only solution is to increase LOD distance.

[ulf.schroeter]

We can't eliminate cracks between patch and surface level when LOD distance is too close. The only solution is to increase LOD distance.

 

Hi Alexander, could you give us a short technical reason for this problem ? Border tesselation between patch and surface level is already perfectly matching, so why is it not possible to adjust border height values of surface patch to same height values as adjacent patch tile border vertices ?

 

Increase of LOD distance is possible, but we would like to limit more complex patch detail material rendering to short distances only (as for larger distances these details are not visible at all)

[frustum]

There are two same tessellators for patch and surface levels.

 

They work in same way: high LODs are adapted to low LODs.

We have all vertices and can increase tessellation inside patch or surface tessellation levels.

But we haven't more detailed vertices on first surface LOD level to adapt surface tessellation to patch.

 

Because of this we a skipped LOD level between patches and surfaces: (1, 3, 7, 15) (63, 127, 255, 511)

[ulf.schroeter]

Because of this we a skipped LOD level between patches and surfaces: (1, 3, 7, 15) (63, 127, 255, 511)

 

Based on this concept increasing lod distance just hides crack problem between surfaces and patches, but cannot solve it, right ?