Particles: initial Quick Particles operator

This operator automates the following steps:
1. Create a point cloud object.
2. Create a simulation data block.
3. Add a small particle simulation to the node tree.
4. Add a Simulation modifier to the point cloud object.
5. Reference the particle simulation from the modifier.

You have to go back to frame 1 to start the simulation.
The simulation is not yet cached and cannot be rendered.

The bounding box of the point cloud object is enabled for now,
because otherwise it is hard to select the object.

release/scripts/startup/bl_operators/object_quick_effects.py

@@ -561,9 +561,61 @@ class QuickLiquid(Operator):
         return {'FINISHED'}
 
 
+class QuickParticles(Operator):
+    """Use active object as particle emitter"""
+    bl_idname = "object.quick_particles"
+    bl_label = "Quick Particles"
+
+    @classmethod
+    def poll(cls, context):
+        if not context.preferences.experimental.use_new_particle_system:
+            return False
+        if context.mode != 'OBJECT':
+            return False
+        if context.active_object is None:
+            return False
+        if context.active_object.type != 'MESH':
+            return False
+        return True
+
+    def execute(self, context):
+        pointcloud = bpy.data.pointclouds.new("Particles")
+        pointcloud_object = bpy.data.objects.new("Particles", pointcloud)
+        modifier = pointcloud_object.modifiers.new("Simulation", 'SIMULATION')
+        simulation = bpy.data.simulations.new("Particle Simulation")
+        tree = simulation.node_tree
+
+        default_name = "Particles"
+        particle_simulation_node = tree.nodes.new('SimulationNodeParticleSimulation')
+        particle_simulation_node.name = default_name
+        emitter_node = tree.nodes.new('SimulationNodeParticleMeshEmitter')
+        emitter_node.location.x -= 200
+        emitter_node.location.y += 50
+        emitter_node.inputs["Object"].default_value = context.active_object
+        force_node = tree.nodes.new('SimulationNodeForce')
+        force_node.location.x -= 200
+        force_node.location.y -= 100
+        force_node.inputs["Force"].default_value = (0, 0, -1)
+
+        tree.links.new(particle_simulation_node.inputs["Emitters"], emitter_node.outputs["Emitter"])
+        tree.links.new(particle_simulation_node.inputs["Forces"], force_node.outputs["Force"])
+
+        modifier.simulation = simulation
+        modifier.data_path = default_name
+
+        for obj in context.selected_objects:
+            obj.select_set(False)
+
+        context.collection.objects.link(pointcloud_object)
+        pointcloud_object.select_set(True)
+        context.view_layer.objects.active = pointcloud_object
+        pointcloud_object.show_bounds = True
+        return {'FINISHED'}
+
 classes = (
     QuickExplode,
     QuickFur,
     QuickSmoke,
     QuickLiquid,
+    QuickParticles,
 )