Creating a geometry from a Python array

Question

I would like to 3D print this image, which I computed in numpy as an array.

My hope is to put this into Blender and export as an STL file to give to my friend at MakerBot.

This is a 2D image but my plan is to thicken the image slightly to have a 3rd dimension.

How do I draw this array in Blender ?

Answer 1

Here are some solutions:

1:

1) export your drawing in Python (numpy) as SVG file (say using MatPlotLib)
2) import SVG file into Blender
3) apply bevel to that

2: In the following however we did it in a different way.

1) We traced your image in Inkscape
2) and exported as SVG file.
3) In blender we just made it mesh and applied extrude.

Answer 2

You could construct geometry based on this data, probably the most straightforward method would be to create a 2D curve with Python.

# These coords are just an example and can be any length.
# They can be from a numpy array or loaded from a file.
coords = [
    (0.1, 0.21),
    (0.4, 0.24),
    (0.6, 0.4),
    (0.7, 0.1),
    (-0.2, -0.3),
    ]

import bpy

cu = bpy.data.curves.new(name="MyCurve", type='CURVE')

# setup curve
cu.fill_mode = 'NONE'
cu.extrude = 0.02
cu.bevel_depth = 0.02

# link to scene
ob = bpy.data.objects.new(name="MyObject", object_data=cu)
scene = bpy.context.scene
scene.objects.link(ob)

# fill curve with data
spline = cu.splines.new(type='POLY')
# -1 because we already have a point
spline.points.add(len(coords) - 1)
for i, point in enumerate(spline.points):
    point.co[0:2] = coords[i]

This can be added to the end if you want to convert to a mesh for printing.

# ----------------------------------------
# Optional: Convert to a mesh and cap ends

bpy.ops.object.select_all(action='DESELECT')
scene.objects.active = ob
ob.select = True

bpy.ops.object.convert(target='MESH')
bpy.ops.object.mode_set(mode='EDIT', toggle=False)
bpy.ops.mesh.select_all(action='SELECT')
bpy.ops.mesh.remove_doubles()
bpy.ops.mesh.fill_holes(sides=0)  # cap ends
bpy.ops.object.mode_set(mode='OBJECT', toggle=False)

Answer 3

Make it white lines on black background. Add a displace modifier to a relative high poly plane mesh and use the image as a height map. Apply the modifier. Cut of the bottom with booleans.

To refine it you can use the Decimate and/or Remesh modifier. Then you should be able to 3D-print it.

Don't be afraid to use a really dense mesh. Slicing a dense mesh might take a little bit longer but that is the only drawback.