Cutting holes in terrain - holes fill back in?

#1 You know I had that same problem at one time I think when I was using 1.1.2. I haven't noticed it lately. There is a property under the terrain (In world inpector) under MISC/Empty Squares. You might need to set the number of sqaures that you are not using. I don't know forsure if that will fix it. But makes sense that you might have to do that.
We stripped the alot of the terrain engine out for our current project so I haven't used it in a while so I can't tell you if this is totally right.

#2 Hm, I'll try the head version and see if it is better. Maybe I can integrate whatever fixed it into my branch (I've made other mods to 1.1.2).

#3 Looks like it still happens in head. I think it is because as you move farther away from the terrain, the terrain polys are approximated more roughly, and the bigger triangles probably render unless all the squares contained in them are empty.

The 'workaround', as you can see in the WaterWorld map - is to put a hill or something in front of the entrance so you can't see into the entrance from far away. :-)

#4 I got to playing with this and it only happens when your Terrain block size is set at 8. Any other size won't pop the LOD. Note you have to maintain an even number for the size of the terrain blocks.

Matt

#5 Is anyone working on fixing this?

#6 The problem with this is really not a problem unless your flying over the area. Its the LOD system that snaps the hole closed by increasing the size of the triangle. If your using the holes in a shooter situation then by the time the LOD snaps you wouldn't know it happened.
Other than that I don't think anyone is. Maybe though. Someone might have thought of a way to disable the LOD.

Matt

#7 Disabling the LOD does have disadvantages though - You'll find your FPS drops significantly when your in a large area (such as on the terrain surface). A better way to do this would be to diable the LOD on the terrain object only, thus avoiding having high detail models in hte distance, but still avoiding the problem of the terrain filling in.

#8 When I am walking up to a structure that leads underground, the terrain is covering the entrance. It looks really bad. There has to be a way of changing the LOD code so that the area around a hole doesn't have it's polys messed with.

I am going to fix it. So I would like to know if anyone can tell me what algorithm Torque's terrain engine is based on.

Geomipmapping, Quadtree or ROAM?

#9 I am reading a whitepaper titled "Real-Time Generation of Continuous Levels of Detail for Height Fields", written by Stefan Rottger.
In section 2.2 "Generating the Triangulation" he describes the criteria for triangle subdivision. The second criteria allows for a higher resolution in regions of high surface roughness.

I am trying to determine if the torque engine has a similar criteria for subdivision. If it does I can insert a test to see if the square is empty and keep the higher detail, as if it had a high surface roughness.