Blender api script

To generate a topographic model from a height map we are going to blender Python API. The used python script does the following:

  1. Get path for the used heightmap and output STL
  2. Create a plane and subdivide it. This give a higher number of vertices and looks like a higher 'resolution'. In this current example we use 200 cut which is the maximum for this operation. If a higher vertex count is need the operation can always be redone
  3.  The heightmap image get loaded as a texture and this texture get used for the displacement operation. The displacement strength controls the height of the displacement
  4. A solidify operation is used to give the plane some volume. This could also be done with an extrusion for a cleaner result. But a solidify is easier and in the next operation the this won't matter anyway
  5. A boolean operation is used on the plane to cut it in a circle. The used object for this is a cylinder. The intersection is used for the operation.
  6. Finally the STL is exported. Here only the plane is exported as we choose to export selected objects.
The final result looks like this:

To render this image and run the python script this command is used:
blender -b test2.blend --python Scripts/Topo.py -o //Renders/img -f 1 -- C1.tif test1.stl

The used python script is found bellow:

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import bpy
import bmesh
import sys
from pathlib import Path

# get arguments -- HeightmapPath StlPath 
argv = sys.argv
argv = argv[argv.index("--") + 1:]  # get all args after "--"

#set directory paths
HeightmapPath = str(Path(__file__).parent.parent / "Heightmaps/" / argv[0])
StlPath = str(Path(__file__).parent.parent / "STLs/" / argv[1])
print(HeightmapPath)

# create plane
bpy.ops.mesh.primitive_plane_add()
so = bpy.context.active_object
objects = bpy.data.objects

# create bmesh
me = bpy.context.object.data
bm = bmesh.new()
bm.from_mesh(me)

# subdivide
bmesh.ops.subdivide_edges(bm,
                          edges=bm.edges,
                          cuts=200,
                          use_grid_fill=True,
                          )

bm.to_mesh(me)
bm.free()

# heightmap texture
img = bpy.data.images.load(HeightmapPath)

tex = bpy.data.textures.new("heightmap", 'IMAGE')
tex.image = img


# displace modifier
displace = so.modifiers.new("displace", 'DISPLACE')
displace.texture = bpy.data.textures['heightmap']
displace.strength = 0.05

so.modifiers["displace"]

# solidify modifier
solidify = so.modifiers.new("solidify", 'SOLIDIFY')
solidify.thickness = 0.2

so.modifiers["solidify"]

# Boolean modifier
boolean = so.modifiers.new("boolean",'BOOLEAN')
booleanObject = objects['CircleBoolean']
boolean.object = booleanObject
boolean.operation = 'INTERSECT'

#export STL
bpy.ops.export_mesh.stl(filepath=StlPath, use_mesh_modifiers=True,use_selection = True)

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