Add Show Ground visualization toggle to the viewer

CHANGELOG.md

@@ -22,6 +22,7 @@
 - Add viewer layer system to overlay multiple solvers/models in supported rendering viewers; call `ViewerBase.activate(layer_id)` to route subsequent `set_model` / `log_state` / `log_*` calls into a named layer, `ViewerBase.set_layer_visible()` to toggle layers independently, and `ViewerBase.set_layer_transform()` to position layers side-by-side. See `example_basic_multi_solver_overlay.py`
 - Add `Heightfield.create_from_mesh()` and `newton.utils.rasterize_mesh_to_heightfield()` to build a heightfield collider by ray-casting a `wp.Mesh`, replacing a large static terrain mesh with an equivalent heightfield.
 - Add `ViewerBase.camera_speed` to configure keyboard translation speed for interactive viewers. (#3439)
+- Add a "Show Ground" visualization toggle (`ViewerBase.show_ground`, default on) to hide or show ground-plane shapes in the viewer.
 - Add opt-in DVI forward dynamics to `SolverKamino` through `SolverKamino.Config(dynamics_solver="dvi")`, with sparse and dense execution, DVI-specific diagnostics, and warm-starting. PADMM remains the default.
 - Add SDF contact support for convex-hull shapes with mesh-attached SDFs and opt-in SDF contact generation for box shapes.
 - Add opt-in filtering of static-static, static-kinematic, and kinematic-kinematic contacts during broad-phase collision detection. Set `CollisionPipeline(include_static_kinematic_pairs=False)` to enable filtering; the default preserves existing contact generation. `Model.shape_contact_pairs` remains an unfiltered superset for direct consumers such as `SolverKamino` and hydroelastic SDF setup.

newton/_src/viewer/viewer.py

@@ -567,6 +567,7 @@ def _init_layer_state(self, layer: Layer) -> None:
         layer.show_gaussians = False
         layer.show_collision = False
         layer.show_visual = True
+        layer.show_ground = True
         layer.show_static = False
         layer.show_inertia_boxes = False
         layer.show_hydro_contact_surface = False
@@ -950,7 +951,7 @@ def log_state(self, state: newton.State):
 
         # compute shape transforms and render
         for shapes in self._shape_instances.values():
-            visible = self._should_show_shape(shapes.flags, shapes.static) and not layer_hidden
+            visible = self._should_show_shape(shapes.flags, shapes.static, shapes.geo_type) and not layer_hidden
 
             if visible:
                 shapes.update(state, world_offsets=self.world_offsets, layer_xform=self.layer.xform)
@@ -1918,9 +1919,13 @@ def _hash_geometry(
     def _hash_shape(self, geo_hash, shape_static, shape_flags) -> int:
         return hash((geo_hash, shape_static, shape_flags))
 
-    def _should_show_shape(self, flags: int, is_static: bool) -> bool:
+    def _should_show_shape(self, flags: int, is_static: bool, geo_type: int | None = None) -> bool:
         """Determine if a shape should be visible based on current settings."""
 
+        # A dedicated ground toggle hides plane shapes (e.g. the ground plane).
+        if geo_type is not None and int(geo_type) == int(newton.GeoType.PLANE) and not self.show_ground:
+            return False
+
         has_collide_flag = bool(flags & int(newton.ShapeFlags.COLLIDE_SHAPES))
         has_visible_flag = bool(flags & int(newton.ShapeFlags.VISIBLE))
 

newton/_src/viewer/viewer_gl.py

@@ -1590,7 +1590,7 @@ def log_state(self, state: nt.State):
 
             layer_hidden = self._layer_force_hidden()
             for key, shapes, offset, count in self._packed_groups:
-                visible = self._should_show_shape(shapes.flags, shapes.static) and not layer_hidden
+                visible = self._should_show_shape(shapes.flags, shapes.static, shapes.geo_type) and not layer_hidden
                 colors = shapes.colors if self.model_changed or shapes.colors_changed else None
                 materials = shapes.materials if self.model_changed else None
 

newton/_src/viewer/viewer_gui.py

@@ -826,6 +826,7 @@ def _render_left_panel(self):
                                 "Wireframe Width (px)", renderer.wireframe_line_width, 0.5, 5.0
                             )
                     _changed, viewer.show_visual = imgui.checkbox("Show Visual", viewer.show_visual)
+                    _changed, viewer.show_ground = imgui.checkbox("Show Ground", viewer.show_ground)
                     _changed, viewer.show_inertia_boxes = imgui.checkbox(
                         "Show Inertia Boxes", viewer.show_inertia_boxes
                     )

newton/_src/viewer/viewer_rtx.py

@@ -1291,8 +1291,21 @@ def log_state(self, state: newton.State) -> None:
         else:
             # Render phase: flat arrays (built at end of build phase) handle all shape
             # transform updates in a single kernel launch — no per-batch work needed here.
+            show_ground = self.show_ground
+            show_ground_changed = show_ground != self._last_show_ground
+            layer_hidden = self._layer_force_hidden() if show_ground_changed else False
             for shapes in self._shape_instances.values():
                 shapes.colors_changed = False
+                if show_ground_changed and int(shapes.geo_type) == int(newton.GeoType.PLANE):
+                    qualified = self._qualify(shapes.name)
+                    # Re-derive through the same predicate the build path uses, so
+                    # re-enabling the ground does not override show_visual,
+                    # show_collision, static-shape, or layer rules.
+                    self._pending_instance_visibility[qualified] = (
+                        self._should_show_shape(shapes.flags, shapes.static, shapes.geo_type) and not layer_hidden
+                    )
+            if show_ground_changed:
+                self._last_show_ground = show_ground
 
             self._log_gaussian_shapes(state)
             self._log_non_shape_state(state)
@@ -2063,6 +2076,7 @@ def clear_model(self) -> None:
 
         self._last_state = None
         self._last_control = None
+        self._last_show_ground = True
 
         # reset camera
         self.camera = Camera(width=self._render_width, height=self._render_height, up_axis=self._up_axis)