Custom Microscope Slide Holder (AOCL)

Welcome to the custom-msh repository! If you're new to parametric manufacturing or the Yantra4D platform, you're in the right place. This document is designed to help you understand not just what this project does, but why it's built this way.

Introduction: Welcome to the Era of Hyperobjects

If you've ever 3D printed a file from the internet, you're probably familiar with .stl files. An STL is what we call a Static Mesh—a fixed, rigid shell made of tiny triangles. If a hole is 3 millimeters wide but you only have a 4-millimeter screw, you are out of luck. The intelligence of the design is lost.

This project is different. It is a Bounded 4D Hyperobject.

Instead of a fixed shape, a Hyperobject is a computational definition of a family of objects that exist within a multidimensional parameter space. Written in OpenSCAD (a code-based 3D modeling language), the "object" here is actually a script. You don't download a specific slide holder; you download the recipe to generate infinite variations of a slide holder.

The "4th Dimension" in this context is the potential of the design space itself. It is "Bounded" because the code enforces logical limits (e.g., preventing a wall from becoming so thin it snaps).

The Theory: Common Denominator Geometry (CDG)

Why do we need Hyperobjects? Because of Common Denominator Geometry (CDG).

Originating in aerospace engineering, CDG is the idea that to build complex systems, you need a shared, mathematically rigorous "truth" or interface. In the realm of additive manufacturing, CDG represents the standardized interfaces—the rails, grids, threads, and sockets—that allow a globally distributed community to build compatible infrastructure without centralized coordination.

For this project, the CDG is the specific length, width, clearance, and interaction profile to hold a standard AOCL microscope slide/substrate (default 25.4mm × 25.4mm, supporting rectangular slides up to 76mm × 52mm).

By standardizing this interface in open code:

• You know that any variation you generate will securely hold the glass slide for its configured dimensions.
• You can adjust tolerances for different 3D printers or materials, without breaking the core functionality.
• You empower a "right to repair" and open science ecosystem independent of proprietary, rigid commercial lab hardware.

Standalone Usage

This hyperobject is designed to be fully functional entirely independent of the Yantra4D ecosystem. The core geometry logic relies solely on the open-source BOSL2 standard library.

To use this on your own machine via OpenSCAD:

# Clone the repository and properly pull the BOSL2 library submodule
git clone --recursive https://github.com/madfam-org/custom-msh.git

# Open the files directly in OpenSCAD
# (The code automatically links to the local BOSL2 folder included in the clone)

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Technical Architecture

This repository contains the OpenSCAD generators for a custom substrate holder system tailored for the 1×1 inch AOCL standard. It includes a single holder, a 10-slot staining rack, a 3-rack storage box with snap-fit lid, and assembly views.

The Yantra4D Manifest (project.json)

To make these Hyperobjects usable for non-programmers, this project includes a project.json file. This is the Yantra4D Manifest.

Yantra4D is an open platform that visualizes and configures these parametric models in a web browser. The project.json file acts as the bridge:

1. It reads the OpenSCAD variables (like tolerance_xy or num_slots).
2. It translates them into a user-friendly web interface with sliders and checkboxes.
3. It bundles standard presets (like a "Tight Tolerance" vs "Loose Tolerance" preset).

When you see the tables below, they are derived from this manifest.

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Project Specifications

Version: 2.4.0
Slug: custom-msh
License: CERN-OHL-W-2.0
Official Configurator: Yantra4D

Included Modes (Hyperobject Generators)

ID	Label	SCAD File	Parts	Description
holder	Single Holder	holder.scad	holder_body	Generates a single AOCL substrate holder.
rack	Staining Rack	rack.scad	rack	Generates a rack holding multiple substrates.
multi_rack	Multi-Rack	multi_rack.scad	multi_rack_body	Generates 2–5 contiguous racks joined front-to-back (Y-axis, default) or side-by-side (X-axis) with diamond grid junction guards.
box	Racks Box	box.scad	box_base, box_lid	Generates an outer enclosure for racks (base + lid).
base	Box Base	box.scad	box_base	Box base only (for single-piece printing).
lid	Box Lid	box.scad	box_lid	Box lid only (for single-piece printing).
assembly	Assembly	assembly.scad	rack, box_base, box_lid, slides	Interactive combined assembly view with glass substrates.
library	CDG Library	aocl_lib.scad	N/A	Core underlying geometry math & shapes (imported by others).

Parameters & Data Standards

The following interactive parameters define the bounds of this hyperobject. Notice how the core CDG (the AOCL substrate dimensions) is exposed but defaults to the industry standard.

Name	Type	Default	Range	Description
assembly_level	slider	3	1–3	Assembly detail level (1=rack+slides, 2=+box, 3=+lid). Hidden parameter.
substrate_length	slider	25.4	15.0–76.0 (step 0.1)	Substrate dimension along the rack's Y-axis (front-to-back). AOCL square: 25.4 mm; standard slide: 76 mm
substrate_width	slider	25.4	15.0–52.0 (step 0.1)	Substrate dimension along the rack's Z-axis (slot depth). AOCL square: 25.4 mm; standard slide: 26 mm
stack_along_y	checkbox	Yes	-	Stack racks along Y-axis instead of X-axis
tolerance_xy	slider	0.4	0.1–0.8 (step 0.05)	Horizontal clearance added to pocket/slot openings for FDM shrinkage
tolerance_z	slider	0.2	0.05–0.5 (step 0.05)	Slot width clearance over substrate thickness
wall_thickness	slider	2.0	1.2–4.0 (step 0.2)	Outer structural wall and pillar thickness
holder_thickness	slider	2.0	1.0–30.0 (step 0.5)	Total Z height of the holder block
label_area	checkbox	Yes	-	Subtracts a debossed recess for adding a handwritten or adhesive label
chamfer_pocket	checkbox	Yes	-	Adds a 45° chamfer at pocket entry to guide substrate insertion
num_slots	slider	10	5–15	Number of substrate positions per rack.
handle	checkbox	Yes	-	Sculpts an integrated FDM-printable carrying arch into each side wall via a 45° peaked hull() void — no external handle or support material required
open_bottom	checkbox	Yes	-	Toggles an open crossbar base (less material, cleanable) vs. solid floor
drainage_angle	slider	5	0–15	Slope for fluid runoff (0 = flat). Reserved for future use.
show_numbers	checkbox	Yes	-	Engrave slot identification numbers on the front and back faces. Also requires Quality ($fn) > 0.
numbering_start	slider	1	1–100	First slot number engraved on the rack. Requires Show Slot Numbers ON and Quality ($fn) > 0.
divider_style	checkbox	Yes	-	Full-depth fins (ON) vs. stub ribs at front+back only (OFF)
num_racks	slider	3	1–5	How many racks the box accommodates.
multi_num_racks	slider	3	2–5	How many racks are joined with shared diamond grid guards. Direction controlled by Stack Along Y-Axis.
multi_stack_y	checkbox	Yes	-	ON = racks joined front-to-back (Y-axis, default). OFF = racks joined side-by-side (X-axis).
frame_base_grid	checkbox	Yes	-	Forces the divider fins to extend downwards to the absolute Z=0 floor
side_guards	checkbox	Yes	-	Generates a 1.5mm 45-degree diamond grid lattice as a mid-height retaining wall along the rack sides
fn	slider	32	0–64 (step 8)	Polygon resolution. 0 = auto (fast draft). Higher = slower but detailed.

Configurator Presets

Preset	Modes
Default Holder	holder
Default Staining Rack	rack
Default Multi-Rack (3 Joined)	multi_rack
Default Racks Box	box, base, lid
Staining rack WITH slides	assembly (level 1)
Racks box WITH racks & slides (no lid)	assembly (level 2)
Racks box WITH racks & slides (with lid)	assembly (level 3)

Color Identifiers

ID	Label	Default Color	Notes
holder_body	Holder Body	#4a90d9
rack	Rack	#e5e7eb
multi_rack_body	Multi-Rack Body	#e5e7eb	render_mode 5
box_base	Box Base	#4a90d9
box_lid	Box Lid	#6b7280
slides	Slides	#cce8f4	glass: true

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Generated alongside project.json for integration with Yantra4D