Adds option to set the height of the border in the `TerrainGenerator` (#744)

# Description

Adds a parameter `border_height` to `TerrainGeneratorCfg` to be able to
control the height of the generator border instead of having a
hard-coded value of 1.0m.

## Type of change

- New feature (non-breaking change which adds functionality)

## Checklist

- [x] I have run the [`pre-commit` checks](https://pre-commit.com/) with
`./isaaclab.sh --format`
- [ ] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [ ] I have added tests that prove my fix is effective or that my
feature works
- [x] I have updated the changelog and the corresponding version in the
extension's `config/extension.toml` file
- [x] I have added my name to the `CONTRIBUTORS.md` or my name already
exists there

source/extensions/omni.isaac.lab/config/extension.toml

 [package]
 
 # Note: Semantic Versioning is used: https://semver.org/
-version = "0.20.4"
+version = "0.20.5"
 
 # Description
 title = "Isaac Lab framework for Robot Learning"

source/extensions/omni.isaac.lab/docs/CHANGELOG.rst

 Changelog
 ---------
 
+0.20.5 (2024-08-02)
+~~~~~~~~~~~~~~~~~~~
+
+Added
+^^^^^
+
+* Added :attr:`omni.isaac.lab.terrain.TerrainGeneratorCfg.border_height` to set the height of the border
+  around the terrain.
+
+
 0.20.4 (2024-08-02)
 ~~~~~~~~~~~~~~~~~~~
 

source/extensions/omni.isaac.lab/omni/isaac/lab/terrains/terrain_generator.py

@@ -259,9 +259,13 @@ class TerrainGenerator:
             self.cfg.num_cols * self.cfg.size[1] + 2 * self.cfg.border_width,
         )
         inner_size = (self.cfg.num_rows * self.cfg.size[0], self.cfg.num_cols * self.cfg.size[1])
-        border_center = (self.cfg.num_rows * self.cfg.size[0] / 2, self.cfg.num_cols * self.cfg.size[1] / 2, -0.5)
+        border_center = (
+            self.cfg.num_rows * self.cfg.size[0] / 2,
+            self.cfg.num_cols * self.cfg.size[1] / 2,
+            -self.cfg.border_height / 2,
+        )
         # border mesh
-        border_meshes = make_border(border_size, inner_size, height=1.0, position=border_center)
+        border_meshes = make_border(border_size, inner_size, height=self.cfg.border_height, position=border_center)
         border = trimesh.util.concatenate(border_meshes)
         # update the faces to have minimal triangles
         selector = ~(np.asarray(border.triangles)[:, :, 2] < -0.1).any(1)

source/extensions/omni.isaac.lab/omni/isaac/lab/terrains/terrain_generator_cfg.py

@@ -125,6 +125,9 @@ class TerrainGeneratorCfg:
     border_width: float = 0.0
     """The width of the border around the terrain (in m). Defaults to 0.0."""
 
+    border_height: float = 1.0
+    """The height of the border around the terrain (in m). Defaults to 1.0."""
+
     num_rows: int = 1
     """Number of rows of sub-terrains to generate. Defaults to 1."""