scripts/startup/bl_ui/node_add_menu_geometry.py

@@ -475,7 +475,8 @@ class NODE_MT_category_GEO_POINT(Menu):
 
     def draw(self, context):
         layout = self.layout
-        node_add_menu.add_node_type(layout, "GeometryNodeDistributePointsInVolume")
+        if context.preferences.experimental.use_new_volume_nodes:
+            node_add_menu.add_node_type(layout, "GeometryNodeDistributePointsInGrid")
         node_add_menu.add_node_type(layout, "GeometryNodeDistributePointsOnFaces")
         layout.separator()
         node_add_menu.add_node_type(layout, "GeometryNodePoints")
@@ -717,6 +718,8 @@ class NODE_MT_geometry_node_GEO_VOLUME_OPERATIONS(Menu):
     def draw(self, context):
         layout = self.layout
         node_add_menu.add_node_type(layout, "GeometryNodeVolumeToMesh")
+        if context.preferences.experimental.use_new_volume_nodes:
+            node_add_menu.add_node_type(layout, "GeometryNodeGridToMesh")
         node_add_menu.draw_assets_for_catalog(layout, "Volume/Operations")
 
 

source/blender/blenkernel/BKE_node.hh

@@ -1333,6 +1333,8 @@ void BKE_nodetree_remove_layer_n(struct bNodeTree *ntree, struct Scene *scene, i
 #define GEO_NODE_MESH_TO_DENSITY_GRID 2126
 #define GEO_NODE_MESH_TO_SDF_GRID 2127
 #define GEO_NODE_POINTS_TO_SDF_GRID 2128
+#define GEO_NODE_GRID_TO_MESH 2129
+#define GEO_NODE_DISTRIBUTE_POINTS_IN_GRID 2130
 
 /** \} */
 

source/blender/blenkernel/BKE_volume_to_mesh.hh

@@ -44,6 +44,8 @@ Mesh *volume_to_mesh(const openvdb::GridBase &grid,
                      float threshold,
                      float adaptivity);
 
+Mesh *volume_grid_to_mesh(const openvdb::GridBase &grid, float threshold, float adaptivity);
+
 /**
  * Convert an OpenVDB volume grid to corresponding mesh data: vertex positions and quad and
  * triangle indices.

source/blender/blenkernel/intern/volume_to_mesh.cc

@@ -184,6 +184,13 @@ Mesh *volume_to_mesh(const openvdb::GridBase &grid,
   return mesh;
 }
 
+Mesh *volume_grid_to_mesh(const openvdb::GridBase &grid,
+                          const float threshold,
+                          const float adaptivity)
+{
+  return volume_to_mesh(grid, {VOLUME_TO_MESH_RESOLUTION_MODE_GRID}, threshold, adaptivity);
+}
+
 #endif /* WITH_OPENVDB */
 
 }  // namespace blender::bke

source/blender/nodes/NOD_static_types.h

@@ -326,6 +326,7 @@ DefNode(GeometryNode, GEO_NODE_CURVE_TOPOLOGY_CURVE_OF_POINT, 0, "CURVE_OF_POINT
 DefNode(GeometryNode, GEO_NODE_CURVE_TOPOLOGY_POINTS_OF_CURVE, 0, "POINTS_OF_CURVE", PointsOfCurve, "Points of Curve", "Retrieve a point index within a curve")
 DefNode(GeometryNode, GEO_NODE_DEFORM_CURVES_ON_SURFACE, 0, "DEFORM_CURVES_ON_SURFACE", DeformCurvesOnSurface, "Deform Curves on Surface", "Translate and rotate curves based on changes between the object's original and evaluated surface mesh")
 DefNode(GeometryNode, GEO_NODE_DELETE_GEOMETRY, 0, "DELETE_GEOMETRY", DeleteGeometry, "Delete Geometry", "Remove selected elements of a geometry")
+DefNode(GeometryNode, GEO_NODE_DISTRIBUTE_POINTS_IN_GRID, 0, "DISTRIBUTE_POINTS_IN_GRID", DistributePointsInGrid, "Distribute Points in Grid", "Generate points inside a volume grid")
 DefNode(GeometryNode, GEO_NODE_DISTRIBUTE_POINTS_IN_VOLUME, 0, "DISTRIBUTE_POINTS_IN_VOLUME", DistributePointsInVolume, "Distribute Points in Volume", "Generate points inside a volume")
 DefNode(GeometryNode, GEO_NODE_DISTRIBUTE_POINTS_ON_FACES, def_geo_distribute_points_on_faces, "DISTRIBUTE_POINTS_ON_FACES", DistributePointsOnFaces, "Distribute Points on Faces", "Generate points spread out on the surface of a mesh")
 DefNode(GeometryNode, GEO_NODE_DUAL_MESH, 0, "DUAL_MESH", DualMesh, "Dual Mesh", "Convert Faces into vertices and vertices into faces")
@@ -341,6 +342,7 @@ DefNode(GeometryNode, GEO_NODE_FILLET_CURVE, 0, "FILLET_CURVE", FilletCurve, "Fi
 DefNode(GeometryNode, GEO_NODE_FLIP_FACES, 0, "FLIP_FACES", FlipFaces, "Flip Faces", "Reverse the order of the vertices and edges of selected faces, flipping their normal direction")
 DefNode(GeometryNode, GEO_NODE_GEOMETRY_TO_INSTANCE, 0, "GEOMETRY_TO_INSTANCE", GeometryToInstance, "Geometry to Instance", "Convert each input geometry into an instance, which can be much faster than the Join Geometry node when the inputs are large")
 DefNode(GeometryNode, GEO_NODE_GET_NAMED_GRID, 0, "GET_NAMED_GRID", GetNamedGrid, "Get Named Grid", "Get volume grid from a volume geometry with the specified name")
+DefNode(GeometryNode, GEO_NODE_GRID_TO_MESH, 0, "GRID_TO_MESH", GridToMesh, "Grid to Mesh", "Generate a mesh on the \"surface\" of a volume grid")
 DefNode(GeometryNode, GEO_NODE_IMAGE_INFO, 0, "IMAGE_INFO", ImageInfo, "Image Info", "Retrieve information about an image")
 DefNode(GeometryNode, GEO_NODE_IMAGE_TEXTURE, def_geo_image_texture, "IMAGE_TEXTURE", ImageTexture, "Image Texture", "Sample values from an image texture")
 DefNode(GeometryNode, GEO_NODE_IMAGE, def_geo_image, "IMAGE", InputImage, "Image", "Input image")

source/blender/nodes/geometry/CMakeLists.txt

@@ -64,6 +64,7 @@ set(SRC
   nodes/node_geo_curve_trim.cc
   nodes/node_geo_deform_curves_on_surface.cc
   nodes/node_geo_delete_geometry.cc
+  nodes/node_geo_distribute_points_in_grid.cc
   nodes/node_geo_distribute_points_in_volume.cc
   nodes/node_geo_distribute_points_on_faces.cc
   nodes/node_geo_dual_mesh.cc
@@ -78,6 +79,7 @@ set(SRC
   nodes/node_geo_flip_faces.cc
   nodes/node_geo_geometry_to_instance.cc
   nodes/node_geo_get_named_grid.cc
+  nodes/node_geo_grid_to_mesh.cc
   nodes/node_geo_image.cc
   nodes/node_geo_image_info.cc
   nodes/node_geo_image_texture.cc

source/blender/nodes/geometry/nodes/node_geo_distribute_points_in_grid.cc

@@ -0,0 +1,277 @@
+/* SPDX-FileCopyrightText: 2023 Blender Authors
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later */
+
+#ifdef WITH_OPENVDB
+#  include <openvdb/openvdb.h>
+#  include <openvdb/tools/Interpolation.h>
+#  include <openvdb/tools/PointScatter.h>
+#endif
+
+#include "DNA_node_types.h"
+#include "DNA_pointcloud_types.h"
+
+#include "BKE_pointcloud.hh"
+#include "BKE_volume.hh"
+#include "BKE_volume_grid.hh"
+
+#include "NOD_rna_define.hh"
+
+#include "UI_interface.hh"
+#include "UI_resources.hh"
+
+#include "GEO_randomize.hh"
+
+#include "node_geometry_util.hh"
+
+namespace blender::nodes::node_geo_distribute_points_in_grid_cc {
+
+enum class DistributeMode {
+  Random = 0,
+  Grid = 1,
+};
+
+static void node_declare(NodeDeclarationBuilder &b)
+{
+  b.add_input<decl::Float>("Grid").hide_value();
+  b.add_input<decl::Float>("Density")
+      .default_value(1.0f)
+      .min(0.0f)
+      .max(100000.0f)
+      .subtype(PROP_NONE)
+      .description(
+          "When combined with each voxel's value, determines the number of points to sample per "
+          "unit volume");
+  b.add_input<decl::Int>("Seed").min(-10000).max(10000).description(
+      "Seed used by the random number generator to generate random points");
+  b.add_input<decl::Vector>("Spacing")
+      .default_value({0.3, 0.3, 0.3})
+      .min(0.0001f)
+      .subtype(PROP_XYZ)
+      .description("Spacing between grid points");
+  b.add_input<decl::Float>("Threshold")
+      .default_value(0.1f)
+      .min(0.0f)
+      .max(FLT_MAX)
+      .description("Minimum density of a voxel to contain a grid point");
+  b.add_output<decl::Geometry>("Points").propagate_all();
+}
+
+static void node_layout(uiLayout *layout, bContext * /*C*/, PointerRNA *ptr)
+{
+  uiItemR(layout, ptr, "mode", UI_ITEM_NONE, "", ICON_NONE);
+}
+
+static void node_init(bNodeTree * /*tree*/, bNode *node)
+{
+  node->custom1 = int16_t(DistributeMode::Random);
+}
+
+static void node_update(bNodeTree *ntree, bNode *node)
+{
+  const auto mode = DistributeMode(node->custom1);
+
+  bNodeSocket *sock_density = static_cast<bNodeSocket *>(node->inputs.first)->next;
+  bNodeSocket *sock_seed = sock_density->next;
+  bNodeSocket *sock_spacing = sock_seed->next;
+  bNodeSocket *sock_threshold = sock_spacing->next;
+
+  bke::nodeSetSocketAvailability(ntree, sock_density, mode == DistributeMode::Random);
+  bke::nodeSetSocketAvailability(ntree, sock_seed, mode == DistributeMode::Random);
+  bke::nodeSetSocketAvailability(ntree, sock_spacing, mode == DistributeMode::Grid);
+  bke::nodeSetSocketAvailability(ntree, sock_threshold, mode == DistributeMode::Grid);
+}
+
+#ifdef WITH_OPENVDB
+/* Implements the interface required by #openvdb::tools::NonUniformPointScatter. */
+class PositionsVDBWrapper {
+ private:
+  float3 offset_fix_;
+  Vector<float3> &vector_;
+
+ public:
+  PositionsVDBWrapper(Vector<float3> &vector, const float3 &offset_fix)
+      : offset_fix_(offset_fix), vector_(vector)
+  {
+  }
+  PositionsVDBWrapper(const PositionsVDBWrapper &wrapper) = default;
+
+  void add(const openvdb::Vec3R &pos)
+  {
+    vector_.append(float3(float(pos[0]), float(pos[1]), float(pos[2])) + offset_fix_);
+  }
+};
+
+/* Use #std::mt19937 as a random number generator. It has a very long period and thus there should
+ * be no visible patterns in the generated points. */
+using RNGType = std::mt19937;
+/* Non-uniform scatter allows the amount of points to be scaled with the volume's density. */
+using NonUniformPointScatterVDB =
+    openvdb::tools::NonUniformPointScatter<PositionsVDBWrapper, RNGType>;
+
+static void point_scatter_density_random(const openvdb::FloatGrid &grid,
+                                         const float density,
+                                         const int seed,
+                                         Vector<float3> &r_positions)
+{
+  /* Offset points by half a voxel so that grid points are aligned with world grid points. */
+  const float3 offset_fix = {0.5f * float(grid.voxelSize().x()),
+                             0.5f * float(grid.voxelSize().y()),
+                             0.5f * float(grid.voxelSize().z())};
+  /* Setup and call into OpenVDB's point scatter API. */
+  PositionsVDBWrapper vdb_position_wrapper(r_positions, offset_fix);
+  RNGType random_generator(seed);
+  NonUniformPointScatterVDB point_scatter(vdb_position_wrapper, density, random_generator);
+  point_scatter(grid);
+}
+
+static void point_scatter_density_grid(const openvdb::FloatGrid &grid,
+                                       const float3 spacing,
+                                       const float threshold,
+                                       Vector<float3> &r_positions)
+{
+  const openvdb::Vec3d half_voxel(0.5, 0.5, 0.5);
+  const openvdb::Vec3d voxel_spacing(double(spacing.x) / grid.voxelSize().x(),
+                                     double(spacing.y) / grid.voxelSize().y(),
+                                     double(spacing.z) / grid.voxelSize().z());
+
+  /* Abort if spacing is zero. */
+  const double min_spacing = std::min(voxel_spacing.x(),
+                                      std::min(voxel_spacing.y(), voxel_spacing.z()));
+  if (std::abs(min_spacing) < 0.0001) {
+    return;
+  }
+
+  /* Iterate through tiles and voxels on the grid. */
+  for (openvdb::FloatGrid::ValueOnCIter cell = grid.cbeginValueOn(); cell; ++cell) {
+    /* Check if the cell's value meets the minimum threshold. */
+    if (cell.getValue() < threshold) {
+      continue;
+    }
+    /* Compute the bounding box of each tile/voxel. */
+    const openvdb::CoordBBox bbox = cell.getBoundingBox();
+    const openvdb::Vec3d box_min = bbox.min().asVec3d() - half_voxel;
+    const openvdb::Vec3d box_max = bbox.max().asVec3d() + half_voxel;
+
+    /* Pick a starting point rounded up to the nearest possible point. */
+    double abs_spacing_x = std::abs(voxel_spacing.x());
+    double abs_spacing_y = std::abs(voxel_spacing.y());
+    double abs_spacing_z = std::abs(voxel_spacing.z());
+    const openvdb::Vec3d start(ceil(box_min.x() / abs_spacing_x) * abs_spacing_x,
+                               ceil(box_min.y() / abs_spacing_y) * abs_spacing_y,
+                               ceil(box_min.z() / abs_spacing_z) * abs_spacing_z);
+
+    /* Iterate through all possible points in box. */
+    for (double x = start.x(); x < box_max.x(); x += abs_spacing_x) {
+      for (double y = start.y(); y < box_max.y(); y += abs_spacing_y) {
+        for (double z = start.z(); z < box_max.z(); z += abs_spacing_z) {
+          /* Transform with grid matrix and add point. */
+          const openvdb::Vec3d idx_pos(x, y, z);
+          const openvdb::Vec3d local_pos = grid.indexToWorld(idx_pos + half_voxel);
+          r_positions.append({float(local_pos.x()), float(local_pos.y()), float(local_pos.z())});
+        }
+      }
+    }
+  }
+}
+
+#endif /* WITH_OPENVDB */
+
+static void node_geo_exec(GeoNodeExecParams params)
+{
+#ifdef WITH_OPENVDB
+  const bke::VolumeGrid<float> volume_grid = params.extract_input<bke::VolumeGrid<float>>("Grid");
+  if (!volume_grid) {
+    params.set_default_remaining_outputs();
+    return;
+  }
+
+  bke::VolumeTreeAccessToken tree_token;
+  const openvdb::GridBase &base_grid = volume_grid.grid(tree_token);
+  if (!base_grid.isType<openvdb::FloatGrid>()) {
+    params.set_default_remaining_outputs();
+    return;
+  }
+  const openvdb::FloatGrid &grid = static_cast<const openvdb::FloatGrid &>(base_grid);
+
+  const DistributeMode mode = DistributeMode(params.node().custom1);
+
+  float density;
+  int seed;
+  float3 spacing{0, 0, 0};
+  float threshold;
+  if (mode == DistributeMode::Random) {
+    density = params.extract_input<float>("Density");
+    seed = params.extract_input<int>("Seed");
+  }
+  else if (mode == DistributeMode::Grid) {
+    spacing = params.extract_input<float3>("Spacing");
+    threshold = params.extract_input<float>("Threshold");
+  }
+
+  Vector<float3> positions;
+  switch (mode) {
+    case DistributeMode::Random:
+      point_scatter_density_random(grid, density, seed, positions);
+      break;
+    case DistributeMode::Grid:
+      point_scatter_density_grid(grid, spacing, threshold, positions);
+      break;
+  }
+
+  PointCloud *pointcloud = BKE_pointcloud_new_nomain(positions.size());
+  pointcloud->positions_for_write().copy_from(positions);
+
+  geometry::debug_randomize_point_order(pointcloud);
+
+  params.set_output("Points", GeometrySet::from_pointcloud(pointcloud));
+#else
+  node_geo_exec_with_missing_openvdb(params);
+#endif
+}
+
+static void node_rna(StructRNA *srna)
+{
+  static const EnumPropertyItem mode_items[] = {
+      {int(DistributeMode::Random),
+       "DENSITY_RANDOM",
+       0,
+       "Random",
+       "Distribute points randomly inside of the volume"},
+      {int(DistributeMode::Grid),
+       "DENSITY_GRID",
+       0,
+       "Grid",
+       "Distribute the points in a grid pattern inside of the volume"},
+      {0, nullptr, 0, nullptr, nullptr},
+  };
+
+  RNA_def_node_enum(srna,
+                    "mode",
+                    "Distribution Method",
+                    "Method to use for scattering points",
+                    mode_items,
+                    NOD_inline_enum_accessors(custom1),
+                    int(DistributeMode::Random));
+}
+
+static void node_register()
+{
+  static bNodeType ntype;
+  geo_node_type_base(&ntype,
+                     GEO_NODE_DISTRIBUTE_POINTS_IN_GRID,
+                     "Distribute Points in Grid",
+                     NODE_CLASS_GEOMETRY);
+  ntype.initfunc = node_init;
+  ntype.updatefunc = node_update;
+  blender::bke::node_type_size(&ntype, 170, 100, 320);
+  ntype.declare = node_declare;
+  ntype.geometry_node_execute = node_geo_exec;
+  ntype.draw_buttons = node_layout;
+  nodeRegisterType(&ntype);
+
+  node_rna(ntype.rna_ext.srna);
+}
+NOD_REGISTER_NODE(node_register)
+
+}  // namespace blender::nodes::node_geo_distribute_points_in_grid_cc

source/blender/nodes/geometry/nodes/node_geo_grid_to_mesh.cc

@@ -0,0 +1,56 @@
+/* SPDX-FileCopyrightText: 2024 Blender Authors
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later */
+
+#include "BKE_material.h"
+#include "BKE_volume_grid.hh"
+#include "BKE_volume_to_mesh.hh"
+
+#include "GEO_randomize.hh"
+
+#include "node_geometry_util.hh"
+
+namespace blender::nodes::node_geo_grid_to_mesh_cc {
+
+static void node_declare(NodeDeclarationBuilder &b)
+{
+  b.add_input<decl::Float>("Grid").hide_value();
+  b.add_input<decl::Float>("Threshold")
+      .default_value(0.1f)
+      .description("Values larger than the threshold are inside the generated mesh");
+  b.add_input<decl::Float>("Adaptivity").min(0.0f).max(1.0f).subtype(PROP_FACTOR);
+  b.add_output<decl::Geometry>("Mesh");
+}
+
+static void node_geo_exec(GeoNodeExecParams params)
+{
+#ifdef WITH_OPENVDB
+  const bke::VolumeGrid<float> grid = params.extract_input<bke::VolumeGrid<float>>("Grid");
+  if (!grid) {
+    params.set_default_remaining_outputs();
+    return;
+  }
+  bke::VolumeTreeAccessToken tree_token;
+  Mesh *mesh = bke::volume_grid_to_mesh(grid.get().grid(tree_token),
+                                        params.extract_input<float>("Threshold"),
+                                        params.extract_input<float>("Adaptivity"));
+  BKE_id_material_eval_ensure_default_slot(&mesh->id);
+  geometry::debug_randomize_mesh_order(mesh);
+  params.set_output("Mesh", GeometrySet::from_mesh(mesh));
+#else
+  node_geo_exec_with_missing_openvdb(params);
+#endif
+}
+
+static void node_register()
+{
+  static bNodeType ntype;
+
+  geo_node_type_base(&ntype, GEO_NODE_GRID_TO_MESH, "Grid to Mesh", NODE_CLASS_GEOMETRY);
+  ntype.declare = node_declare;
+  ntype.geometry_node_execute = node_geo_exec;
+  nodeRegisterType(&ntype);
+}
+NOD_REGISTER_NODE(node_register)
+
+}  // namespace blender::nodes::node_geo_grid_to_mesh_cc