3d printed flap cleanup (#260)

Base of this pull request is the flap3dcleanup branch - those changes
had this description from Scott:

- follow typical generate_ patterns for the script
    - make script executable
    - support font specification and custom text
    - don't require specifying input/output directories
    - export multiple flaps in parallel w/ threadpool rendering
- revert changes to flap.scad example rendering; extract the
3dp-specific setup to flap_3dp.scad file

Additional changes are:
- Update the generate_3d_print_flaps.py file to just call openscad
directly for each of the needed files (flap and letters) instead of
doing a single call and then trying to split the output by color.
- Update flap_3dp.scad:
  - Change the flap STL to subtract out the letters
- Add support for generating just the flap or just the letters or both
at the same time

---------

Co-authored-by: Scott Bezek <scottbez1@gmail.com>

Author: RainyDayHiker

.gitignore

@@ -22,3 +22,6 @@ sensor.xml
 *.hex
 
 .pio
+.vscode
+.nvmrc
+.python_version

3d/flap.scad

@@ -39,15 +39,6 @@ letter_facet_number = 100;
 vertical_keepout_mode = 1;              // 0=ignore; 1=highlight; 2=cut
 vertical_keepout_size_factor = 1.1;     // Expand calculated keepout region by this factor. 1=no expansion, 1.5=50% expansion, etc
 
-// generate lower half of the flap
-generate_second_half = true;
-
-// index number of flap, see flap_characters.scad
-flap_number = 1;
-
-// generate 3d printable flap for 0.15mm layer height
-print_3d = false;
-
 vertical_keepout_size = get_flap_arc_separation() * vertical_keepout_size_factor;
 font_extrusion_3d = 0.3;
 font_extrusion = 0.1;
@@ -218,11 +209,12 @@ module flap_with_letters(flap_color, letter_color, flap_index, flap_gap, flap=tr
     }
 }
 
-flap_gap = get_flap_gap();
-flap_with_letters([1,0,0], [1,1,0], flap_index=flap_number, flap_gap=flap_gap, bleed=0, print_3d=true);
-translate([0, -flap_pin_width-flap_gap, 0])
-if (generate_second_half) {
-    rotate([180, 0, 0]) {
-        flap_with_letters([1,0,0], [1,1,0], flap_index=flap_number - 1, flap_gap=flap_gap, bleed=0, print_3d=true);
-    }
+// Example:
+i = 1;
+gap = 5;
+
+flap_with_letters([1,0,0], [1,1,0], flap_index=i, flap_gap=gap, bleed=2);
+translate([0, -flap_pin_width-gap, 0])
+rotate([180, 0, 0]) {
+    flap_with_letters([1,0,0], [1,1,0], flap_index=i - 1, flap_gap=gap, bleed=2);
 }

3d/flap_3dp.scad

@@ -0,0 +1,43 @@
+/*
+   Copyright 2025 Scott Bezek and the splitflap contributors
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+use<flap.scad>;
+
+// TODO: extract core flap spool dimensions used for flap gap instead of using the full splitflap file
+use<splitflap.scad>;
+
+generateFullFlap = false; // If true, generates the full flap STL
+generateText = false; // If generateFullFlap is false, this controls what part of the STL to generate
+generateFrontText = true; // If generateText is true, this controls generation of the front text
+generateBackText = true; // If generateText is true, this controls generation of the back text
+
+flap_number = 0;
+
+flap_gap = get_flap_gap();
+if (generateFullFlap) {
+	// Generate the full flap using the standard function
+    flap_with_letters([0,0,0], [1,1,1], flap_index=flap_number, flap_gap=flap_gap, bleed=0, print_3d=true);
+} else {
+    if (generateText == false) {
+		// Generate just the flap STL with the letters removed
+        difference() {
+            flap_with_letters([0,0,0], [1,1,1], front_letter=false, back_letter=false, flap_index=flap_number, flap_gap=flap_gap, bleed=0, print_3d=true);
+            flap_with_letters([0,0,0], [1,1,1], flap=false, flap_index=flap_number, flap_gap=flap_gap, bleed=0, print_3d=true);
+        }
+    } else {
+		// Generate just the letters STL
+        flap_with_letters([0,0,0], [1,1,1], front_letter=generateFrontText, back_letter=generateBackText, flap=false, flap_index=flap_number, flap_gap=flap_gap, bleed=0, print_3d=true);
+    }
+}

3d/font_generator.scad

@@ -66,11 +66,10 @@ bleed = 0;                      // Amount of bleed (in mm) for text to expand be
 
 flap_color = [1,1,1];
 letter_color = [0,0,0];
+print_3d = false;
 
 render_alignment_marks = false; // Whether to render markings to help with alignment/registration (e.g. for screen printing)
 
-print_3d = false; // embeds and substracts a 0.3mm think font into the flap. Used together with colored_stl_exporter.py
-
 // ---------------------------
 // End configurable parameters
 // ---------------------------

3d/scripts/colored_flap_exporter.py

@@ -0,0 +1,144 @@
+#!/usr/bin/env python3
+
+#   Copyright 2025 Scott Bezek and the splitflap contributors
+#
+#   Licensed under the Apache License, Version 2.0 (the "License");
+#   you may not use this file except in compliance with the License.
+#   You may obtain a copy of the License at
+#
+#       http://www.apache.org/licenses/LICENSE-2.0
+#
+#   Unless required by applicable law or agreed to in writing, software
+#   distributed under the License is distributed on an "AS IS" BASIS,
+#   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#   See the License for the specific language governing permissions and
+#   limitations under the License.
+
+
+from __future__ import division
+from __future__ import print_function
+
+import argparse
+import logging
+import os
+import sys
+import time
+import openscad
+
+from multiprocessing.dummy import Pool
+from shutil import rmtree
+
+script_dir = os.path.dirname(os.path.abspath(__file__))
+source_parts_dir = os.path.dirname(script_dir)
+repo_root = os.path.dirname(source_parts_dir)
+sys.path.append(repo_root)
+
+from util import file_util
+
+if __name__ == "__main__":
+    logging.basicConfig(level=logging.DEBUG)
+
+    parser = argparse.ArgumentParser()
+    parser.add_argument(
+        "-f",
+        "--font",
+        type=str,
+        help="Name of font preset to use - see flap_fonts.scad",
+    )
+    parser.add_argument("-t", "--text", type=str, help="String of text to generate")
+    parser.add_argument(
+        "--vertical-keepout-clip",
+        action="store_true",
+        help="Clip letters that violate vertical keepout zones",
+    )
+    parser.add_argument(
+        "--single-stl",
+        action="store_true",
+        default=False,
+        help="Generate a single STL file for each flap",
+    )
+    parser.add_argument(
+        "--single-letter-stl",
+        action="store_true",
+        default=False,
+        help="Generate a single STL file for the front and back letters (only used if --single-stl is not set)",
+    )
+    parser.add_argument(
+        "--parallelism",
+        type=int,
+        help="How many OpenSCAD exports to run in parallel. Defaults to CPU count if unspecified.",
+        default=None,
+    )
+    args = parser.parse_args()
+
+    extra_variables = {}
+
+    if args.font is not None:
+        extra_variables["font_preset"] = args.font
+
+    if args.text is not None:
+        extra_variables["character_list"] = args.text
+
+    if args.vertical_keepout_clip:
+        extra_variables["vertical_keepout_mode"] = 2
+
+    output_directory = os.path.join(source_parts_dir, "build", "flap_3dp")
+    rmtree(output_directory, ignore_errors=True)
+
+    def render_flap(flap_number):
+        flap_path = os.path.join(output_directory, f"flap_{flap_number:02}")
+        file_util.mkdir_p(flap_path)
+        openscad_variables = {
+            "flap_number": flap_number,
+            "generateFullFlap": args.single_stl,
+            "generateText": False,
+        }
+        openscad_variables.update(extra_variables)
+
+        openscad.run(
+            os.path.join(source_parts_dir, "flap_3dp.scad"),
+            os.path.join(flap_path, f"{flap_number:02}_flap.stl"),
+            variables=openscad_variables,
+            capture_output=True,
+        )
+
+        if not args.single_stl:
+            if args.single_letter_stl:
+                openscad_variables["generateText"] = True
+                openscad.run(
+                    os.path.join(source_parts_dir, "flap_3dp.scad"),
+                    os.path.join(flap_path, f"{flap_number:02}_letters.stl"),
+                    variables=openscad_variables,
+                    capture_output=True,
+                    ignore_empty_top_level_object=True,
+                )
+            else:
+                openscad_variables["generateText"] = True
+                openscad_variables["generateFrontText"] = True
+                openscad_variables["generateBackText"] = False
+                openscad.run(
+                    os.path.join(source_parts_dir, "flap_3dp.scad"),
+                    os.path.join(flap_path, f"{flap_number:02}_letter_front.stl"),
+                    variables=openscad_variables,
+                    capture_output=True,
+                    ignore_empty_top_level_object=True,
+                )
+
+                openscad_variables["generateText"] = True
+                openscad_variables["generateFrontText"] = False
+                openscad_variables["generateBackText"] = True
+                openscad.run(
+                    os.path.join(source_parts_dir, "flap_3dp.scad"),
+                    os.path.join(flap_path, f"{flap_number:02}_letter_back.stl"),
+                    variables=openscad_variables,
+                    capture_output=True,
+                    ignore_empty_top_level_object=True,
+                )
+
+    pool = Pool(args.parallelism)
+    num_flaps = len(args.text) if args.text is not None else 52
+    for _ in pool.imap_unordered(render_flap, range(num_flaps)):
+        # Consume results as they occur so any exception is rethrown
+        pass
+    pool.close()
+    pool.join()

3d/scripts/generate_3d_print_flaps.py

@@ -51,6 +51,7 @@ def run(
         variables=None,
         capture_output=False,
         colorscheme=None,
+        ignore_empty_top_level_object=False,
         ):
 
     command = [
@@ -96,6 +97,10 @@ def run(
 
     logger.info(command)
 
+    if ignore_empty_top_level_object:
+        # In order to ignore empty top level object errors, we need to be able to look at stderr
+        capture_output = True
+
     stdout_type = subprocess.PIPE if capture_output else None
     stderr_type = subprocess.PIPE if capture_output else None
     try:
@@ -111,7 +116,10 @@ def run(
 
     logger.debug('returncode:%d', returncode)
     if returncode != 0:
-        raise OpenSCADException('openscad returned non-zero!', returncode, stdout=stdout, stderr=stderr)
+        if ignore_empty_top_level_object and b'Current top level object is empty.' in stderr:
+            logger.info('Ignoring empty top level object!')
+        else:
+            raise OpenSCADException('openscad returned non-zero!', returncode, stdout=stdout, stderr=stderr)
     return stdout, stderr