Using surface( file = "Flourish_01b.png" ) on this png file:

[image: Flourish_01b.png]

results in this:

[image: result.png]

Except for the square base, I was surprised it even worked.

Attempting to use pre-built STL files in SCAD always seems to cause a
problem, so I wanted to try using grayscale images instead.

When using BOSL, I can create a nice vnf array from a sweep().  Works
great.  I can then use *vnf_polyhedron() *to draw it or draw copies and
mirrors of it ... whatever.

This is why I was hoping for a function ... however ... as simple as you
say it can be ... I've never touched python in my life and never dealt with
the PNG file structure.

On Tue, May 10, 2022 at 4:23 PM Revar Desmera revarbat@gmail.com wrote:

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Python has libraries for everything so you should be able to read a PNG as
an image and not need to know the file structure.

On Tue, 10 May 2022 at 21:48, Joe Weinpert joe.weinpert@gmail.com wrote:

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On May 10, 2022, at 4:02 PM, Joe Weinpert joe.weinpert@gmail.com wrote:

No doubt ... but  I never used Python.

I think that openSCAD having a way to import and use external STLs by handling them as data arrays would open up many doors. There are thousands upon thousands of STL files out there.  Heck, openSCAD is used for parameter customizing on many within Thingiverse alone.  Currently I use converter https://fenrus75.github.io/FenrusCNCtools/javascript/stl2png.html to convert an STL to a PNG. Super super super basic ... but it does work until I can find something else.

I will continue searching for a converter to take files like the grayscale png picture I posted and make height data maps.  Maybe they will work with the BOSL heightfield() function ... you never know.

On Tue, May 10, 2022 at 5:03 PM nop head <nop.head@gmail.com mailto:nop.head@gmail.com> wrote:
Python has libraries for everything so you should be able to read a PNG as an image and not need to know the file structure.

On Tue, 10 May 2022 at 21:48, Joe Weinpert <joe.weinpert@gmail.com mailto:joe.weinpert@gmail.com> wrote:
Using surface( file = "Flourish_01b.png" ) on this png file:

<Flourish_01b.png>

results in this:

<result.png>

Except for the square base, I was surprised it even worked.

Attempting to use pre-built STL files in SCAD always seems to cause a problem, so I wanted to try using grayscale images instead.

When using BOSL, I can create a nice vnf array from a sweep().  Works great.  I can then use vnf_polyhedron() to draw it or draw copies and mirrors of it ... whatever.

This is why I was hoping for a function ... however ... as simple as you say it can be ... I've never touched python in my life and never dealt with the PNG file structure.

On Tue, May 10, 2022 at 4:23 PM Revar Desmera <revarbat@gmail.com mailto:revarbat@gmail.com> wrote:
BOSL2 has a function/module called heightfield() that you can feed an array of heights, or a function literal that can calculate the heights dynamically.  However, there is currently no way for an OpenSCAD script to read height values from an image file.  You can only generate 3D geometry using surface().

https://github.com/revarbat/BOSL2/wiki/shapes3d.scad#functionmodule-heightfield https://github.com/revarbat/BOSL2/wiki/shapes3d.scad#functionmodule-heightfield

Having said that, it should not be too difficult to write a Python script to read in an image file, and have it write out a .scad source file containing the array of height data.

• Revar

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I wrote up a simple Python image-to-scadfile converter.  It’ll read most
common image types, convert them to Luminosity grayscale, with optional
re-sizing, and output it to a 2-dimensional array in a OpenSCAD source file.

• Revar

Usage:
img2scad.py INFILE -o OUTSCADFILE -v VARNAME -r WIDTHxHEIGHT

Script:

#!env python3

import re
import os
import sys
import os.path
import argparse

from PIL import Image

def img2scad(filename, varname, resize, outf):
indent = " " * 4
im = Image.open(filename).convert('L')
if resize:
print("Resizing to {}x{}".format(resize[0],resize[1]))
im = im.resize(resize)
pix = im.load()
width, height = im.size
print("// Image {} ({}x{})".format(filename, width, height), file=outf)
print("{} = [".format(varname), file=outf)
line = indent
for x in range(width):
line += "[ "
for y in range(height):
line += "{:d}, ".format(pix[x,y])
if len(line) > 60:
print(line, file=outf)
line = indent * 2
line += " ],"
if line != indent:
print(line, file=outf)
line = indent
print("];", file=outf)
print("", file=outf)

def main():
parser = argparse.ArgumentParser(prog='img2scad')
parser.add_argument('-o', '--outfile',
help='Output .scad file.')
parser.add_argument('-v', '--varname',
help='Variable to use in .scad file.')
parser.add_argument('-r', '--resize',
help='Resample image to WIDTHxHEIGHT.')
parser.add_argument('infile', help='Input image file.')
opts = parser.parse_args()

 non_alnum = re.compile(r'[^a-zA-Z0-9_]')
 if not opts.varname:
     if opts.outfile:
         opts.varname =

os.path.splitext(os.path.basename(opts.outfile))[0]
opts.varname = non_alnum.sub("", opts.varname)
else:
opts.varname = "image_data"
size_pat = re.compile(r'^([0-9][0-9])x([0-9][0-9])$')
if opts.resize:
m = size_pat.match(opts.resize)
if not m:
print("Expected WIDTHxHEIGHT resize format.", file=sys.stderr)
sys.exit(-1)
opts.resize = (int(m.group(1)), int(m.group(2)))

 if not opts.varname or non_alnum.search(opts.varname):
     print("Bad variable name: {}".format(opts.varname),

file=sys.stderr)
sys.exit(-1)

 if opts.outfile:
     with open(opts.outfile, "w") as outf:
         img2scad(opts.infile, opts.varname, opts.resize, outf)
 else:
     img2scad(opts.infile, opts.varname, opts.resize, sys.stdout)

 sys.exit(0)

if name == "main":
main()

On May 10, 2022, at 4:02 PM, Joe Weinpert joe.weinpert@gmail.com wrote:

No doubt ... but  I never used Python.

I think that openSCAD having a way to import and use external STLs by
handling them as data arrays would open up many doors. There are thousands
upon thousands of STL files out there.  Heck, openSCAD is used
for parameter customizing on many within Thingiverse alone.  Currently I
use converter
https://fenrus75.github.io/FenrusCNCtools/javascript/stl2png.html to
convert an STL to a PNG. Super super super basic ... but it does work until
I can find something else.

I will continue searching for a converter to take files like the grayscale
png picture I posted and make height data maps.  Maybe they will work with
the BOSL heightfield() function ... you never know.

On Tue, May 10, 2022 at 5:03 PM nop head nop.head@gmail.com wrote:

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On May 10, 2022, at 5:08 PM, Joe Weinpert joe.weinpert@gmail.com wrote:

Holy sh..!  How the heck do you write something THAT fast?

You have my thanks ... and in any way that this can be added to BOSL as some sort of function would be something indeed!

I assume "mg2scad.py" is the file name to save the Python code as ... and your usage example is "run command line" orientated.  But what do I need on my desktop to run python apps?  I've never done a thing with Python that I am aware of.

On Tue, May 10, 2022 at 7:51 PM Revar Desmera <revarbat@gmail.com mailto:revarbat@gmail.com> wrote:
I wrote up a simple Python image-to-scadfile converter.  It’ll read most common image types, convert them to Luminosity grayscale, with optional re-sizing, and output it to a 2-dimensional array in a OpenSCAD source file.

• Revar

Usage:
img2scad.py INFILE -o OUTSCADFILE -v VARNAME -r WIDTHxHEIGHT

Script:
#!env python3

import re
import os
import sys
import os.path
import argparse

from PIL import Image

def img2scad(filename, varname, resize, outf):
indent = " " * 4
im = Image.open(filename).convert('L')
if resize:
print("Resizing to {}x{}".format(resize[0],resize[1]))
im = im.resize(resize)
pix = im.load()
width, height = im.size
print("// Image {} ({}x{})".format(filename, width, height), file=outf)
print("{} = [".format(varname), file=outf)
line = indent
for x in range(width):
line += "[ "
for y in range(height):
line += "{:d}, ".format(pix[x,y])
if len(line) > 60:
print(line, file=outf)
line = indent * 2
line += " ],"
if line != indent:
print(line, file=outf)
line = indent
print("];", file=outf)
print("", file=outf)

def main():
parser = argparse.ArgumentParser(prog='img2scad')
parser.add_argument('-o', '--outfile',
help='Output .scad file.')
parser.add_argument('-v', '--varname',
help='Variable to use in .scad file.')
parser.add_argument('-r', '--resize',
help='Resample image to WIDTHxHEIGHT.')
parser.add_argument('infile', help='Input image file.')
opts = parser.parse_args()

 non_alnum = re.compile(r'[^a-zA-Z0-9_]')
 if not opts.varname:
     if opts.outfile:
         opts.varname = os.path.splitext(os.path.basename(opts.outfile))[0]
         opts.varname = non_alnum.sub("", opts.varname)
     else:
         opts.varname = "image_data"
 size_pat = re.compile(r'^([0-9][0-9]*)x([0-9][0-9]*)$')
 if opts.resize:
     m = size_pat.match(opts.resize)
     if not m:
         print("Expected WIDTHxHEIGHT resize format.", file=sys.stderr)
         sys.exit(-1)
     opts.resize = (int(m.group(1)), int(m.group(2)))

 if not opts.varname or non_alnum.search(opts.varname):
     print("Bad variable name: {}".format(opts.varname), file=sys.stderr)
     sys.exit(-1)

 if opts.outfile:
     with open(opts.outfile, "w") as outf:
         img2scad(opts.infile, opts.varname, opts.resize, outf)
 else:
     img2scad(opts.infile, opts.varname, opts.resize, sys.stdout)

 sys.exit(0)

if name == "main":
main()

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Yes, save the script to the file img2scad.py.  I’m afraid that this is
just a command-line tool, and while it’s easy enough to use on Linux or a
Mac, I’m not truly sure about how to set up a command-line on Windows.  A
quick googling results in
https://www.geeksforgeeks.org/how-to-install-python-on-windows/ which may
be helpful.

This script would probably better fit in a separate BOSL2-helpers
repository.

A GUI version is perfectly possible to do, but that may take me a couple
weeks to refresh my memory on how to do cross-platform.

• Revar

On May 10, 2022, at 5:08 PM, Joe Weinpert joe.weinpert@gmail.com wrote:

Holy sh..!  How the heck do you write something THAT fast?

You have my thanks ... and in any way that this can be added to BOSL as
some sort of function would be something indeed!

I assume "mg2scad.py" is the file name to save the Python code as ... and
your usage example is "run command line" orientated.  But what do I need on
my desktop to run python apps?  I've never done a thing with Python that I
am aware of.

On Tue, May 10, 2022 at 7:51 PM Revar Desmera revarbat@gmail.com wrote:

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On May 10, 2022, at 6:15 PM, Joe Weinpert joe.weinpert@gmail.com wrote:

I am receiving this error msg when I run the script:

Line 10: ModuleNotFoundError: No module named 'PIL'

Any ideas?

On Tue, May 10, 2022 at 8:23 PM Revar Desmera <revarbat@gmail.com mailto:revarbat@gmail.com> wrote:
Yes, save the script to the file img2scad.py.  I’m afraid that this is just a command-line tool, and while it’s easy enough to use on Linux or a Mac, I’m not truly sure about how to set up a command-line on Windows.  A quick googling results in https://www.geeksforgeeks.org/how-to-install-python-on-windows/ https://www.geeksforgeeks.org/how-to-install-python-on-windows/ which may be helpful.

This script would probably better fit in a separate BOSL2-helpers repository.

A GUI version is perfectly possible to do, but that may take me a couple weeks to refresh my memory on how to do cross-platform.

• Revar

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