Use this Python script in Blender to import your downloaded heightmap as a 3D terrain mesh:

import bpy
import os
import glob
from mathutils import Color

# === CONFIGURATION ===
downloads_folder = os.path.expanduser(r"C:\Users\Reference\Downloads")  # <- CHANGE username if needed
filename_pattern = "hex_hmap_*.png"
pixel_size = 1.0   # meters per pixel
max_height = 100.0 # customize this as needed

# === FIND MOST RECENT HEIGHTMAP ===
files = glob.glob(os.path.join(downloads_folder, filename_pattern))
if not files:
    raise FileNotFoundError(f"No files matching {filename_pattern} found in {downloads_folder}")

latest_file = max(files, key=os.path.getmtime)
print(f"Using latest heightmap: {latest_file}")

# === LOAD IMAGE ===
img = bpy.data.images.load(latest_file)

width, height = img.size
pixels = list(img.pixels)  # flat RGBA sequence
print(f"Image size: {width}x{height}")

# === GENERATE HEIGHT DATA (convert grayscale) ===
def get_height(x, y):
    # Each pixel = RGBA (4 values)
    index = (y * width + x) * 4
    r, g, b = pixels[index:index+3]
    grayscale = (r + g + b) / 3.0
    return grayscale * max_height

# === CREATE MESH ===
verts = []
faces = []

for y in range(height):
    for x in range(width):
        z = get_height(x, y)
        verts.append((x * pixel_size, y * pixel_size, z))

for y in range(height - 1):
    for x in range(width - 1):
        v0 = y * width + x
        v1 = v0 + 1
        v2 = v0 + width + 1
        v3 = v0 + width
        faces.append((v0, v1, v2, v3))

# === CREATE OBJECT ===
mesh = bpy.data.meshes.new("TerrainMesh")
mesh.from_pydata(verts, [], faces)
mesh.update()

obj = bpy.data.objects.new("Terrain", mesh)
bpy.context.collection.objects.link(obj)

# === OPTIONAL: SHADE SMOOTH & CENTER ===
bpy.context.view_layer.objects.active = obj
bpy.ops.object.shade_smooth()
bpy.ops.object.origin_set(type='ORIGIN_GEOMETRY', center='BOUNDS')

# Move terrain so bottom is at Z=0
min_z = min(v[2] for v in verts)
obj.location.z -= min_z

print("Terrain successfully created from:", latest_file)