Implement production vertical slice foundation

game/world/sites/vehicle_test_environment.gd

@@ -0,0 +1,33 @@
+class_name VehicleTestEnvironment
+extends Node3D
+
+
+func _ready() -> void:
+	var particles := GPUParticles3D.new()
+	particles.name = "SuspendedParticles"
+	particles.position = Vector3(0.0, -34.0, -42.0)
+	particles.amount = 360
+	particles.lifetime = 14.0
+	particles.preprocess = 14.0
+	particles.visibility_aabb = AABB(
+		Vector3(-50.0, -35.0, -78.0),
+		Vector3(100.0, 70.0, 156.0)
+	)
+
+	var motion := ParticleProcessMaterial.new()
+	motion.emission_shape = ParticleProcessMaterial.EMISSION_SHAPE_BOX
+	motion.emission_box_extents = Vector3(45.0, 28.0, 70.0)
+	motion.direction = Vector3(0.1, 0.04, 0.0)
+	motion.spread = 180.0
+	motion.initial_velocity_min = 0.02
+	motion.initial_velocity_max = 0.09
+	motion.gravity = Vector3.ZERO
+	motion.scale_min = 0.025
+	motion.scale_max = 0.08
+	particles.process_material = motion
+
+	var particle_mesh := SphereMesh.new()
+	particle_mesh.radius = 0.035
+	particle_mesh.height = 0.07
+	particles.draw_pass_1 = particle_mesh
+	add_child(particles)