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Featured Model of the Day

Hose-shaped reducer STL 3D file 220x100 mm to 185x55 mm – transition: 20 mm 📦 #4326

1 object(s) - format STL

gizmo

Latest user-generated 3D models

Tube clip Ø65 mm STL file · Flat head screw Ø6 mm 📦 #10403

1 object(s) - format STL

gizmo

From the Blog

Why Modeling Strategy Matters in Procedural CAD Modeling

2025-12-14 · 3D Modeling · sylvain
why Modeling Strategy Matters in Procedural CAD Modeling why Modeling Strategy Matters in Procedural CAD Modeling

Why does modeling strategy matter so much in procedural CAD? Two scripts can produce the exact same geometry while showing very different generation times.

Using a concrete build123d example, this article explains why certain operations, such as fillets, become expensive when repeated at scale, and how a simple change in approach can drastically reduce computation time.

A clear overview of the key challenges in procedural modeling, highlighting the direct impact of design choices on CAD engine performance.

Read the article

A selection of custom 3D models

📦 Model #2141

1 object(s)
- format STL
Round-to-Rectangular Tube Adapter STL 3D file ⌀100 mm to 50×50 mm, thickness 2 mm
Round-to-Rectangular Tube Adapter STL 3D file ⌀100 mm to 50×50 mm, thickness 2 mm
Download this 3D file in STL format of a round-to-rectangular adapter with an external diameter of ⌀100 mm and a rectangular section with internal dimensions 50×50 mm. The shell thickness is 2 mm and the total length is 200 mm.
Parameter Value Unit
cylinder outer diameter 100 mm
cylinder inlet length 25 mm
rectangle internal length 50 mm
rectangle internal height 50 mm
rectangle inlet length 15 mm
offset Z 0 mm
offset Y 0 mm
total length 200 mm
thickness 2 mm
chamfer no chamfer

📦 Model #3612

1 object(s)
- format STL
Protective grid STL 3D file, center-to-center: 210x110mm, mesh: 10mm - Ø5mm
Protective grid STL 3D file, center-to-center: 210x110mm, mesh: 10mm - Ø5mm
Download this rectangular protective honeycomb grid model in STL format. Mounting holes are placed at the four corners (center-to-center 210x110 mm), each with a diameter of Ø5 mm. The overall dimensions reach 220x120 mm, with very large 10 mm cell size for peak ventilation. This grid serves as both a protective guard and a ventilation panel.
Parameter Value Unit
length or center-to-center 210 mm
width or center-to-center 110 mm
mesh size 10 mm
dual color no
holes yes
hole diameter 5 mm

📦 Model #6362

2 object(s)
- format STL
Rectangular-base box with lid STL 3D model – 84×45×20 mm, wall thickness 2 mm
Rectangular-base box with lid STL 3D model – 84×45×20 mm, wall thickness 2 mm
View of object #0
Rectangular-base box with a lid provided as a STL 3D file. Overall dimensions are 84 mm long, 45 mm wide, and 20 mm tall. The box features thin 2 mm walls. Interior and exterior edges are rounded. A small clearance is included to ensure a precise fit between the box and the lid. The internal dimensions, excluding rounding, are 80 mm × 41 mm × 16 mm.
Parameter Value Unit
length 84 mm
width 45 mm
height 20 mm
wall thikness 2 mm

📦 Model #1483

1 object(s)
- format STL
Tube adapter STL file ⌀ 200–50 mm (Length: 80 mm)
Tube adapter STL file ⌀ 200–50 mm (Length: 80 mm)
Tube reducer ⌀200 mm to ⌀50 mm in STL 3D format. Total length of this junction is 80 mm. The thickness of the tubes is identical: 3 mm. The larger-diameter tube has a sleeve length of 30 mm, the smaller one of 30 mm as well. The ends have no fillet.
Parameter Value Unit
side A length 30 mm
side A outer diameter 200 mm
side A thickness 3 mm
side B length 30 mm
side B outer diameter 50 mm
side B thickness 3 mm
transition length 20 mm
axis offset 0 mm
ends fillet no fillet

📦 Model #2813

1 object(s)
- format STL
Tube adapter STL 3D file ⌀ 150–100 mm (Length: 79 mm)
Tube adapter STL 3D file ⌀ 150–100 mm (Length: 79 mm)
Straight sleeve ⌀150 mm to ⌀100 mm in STL format. Total length of this sleeve is 79 mm. The thickness of the tubes is identical: 3 mm. The larger-diameter tube has a sleeve length of 30 mm, the smaller one of 29 mm. The ends have a fillet to make tube connection easier.
Parameter Value Unit
side A length 30 mm
side A outer diameter 150 mm
side A thickness 3 mm
side B length 29 mm
side B outer diameter 100 mm
side B thickness 3 mm
transition length 20 mm
axis offset 0 mm
ends fillet fillet on bo...

📦 Model #2994

1 object(s)
- format STL
Tubing adapter STL 3D file ⌀ 60–51 mm (Length: 55 mm)
Tubing adapter STL 3D file ⌀ 60–51 mm (Length: 55 mm)
Straight sleeve ⌀60 mm to ⌀51 mm in STL format. Final length of this sleeve is 55 mm. The thickness of the tubes is identical: 2.5 mm. The larger-diameter tube has a sleeve length of 25 mm, the smaller one of 25 mm as well. The ends feature a fillet.
Parameter Value Unit
side A length 25 mm
side A outer diameter 60 mm
side A thickness 2.5 mm
side B length 25 mm
side B outer diameter 51 mm
side B thickness 2.5 mm
transition length 5 mm
axis offset 0 mm
ends fillet fillet on bo...

📦 Model #4396

1 object(s)
- format STL
Honeycomb grid STL file, 250x250mm, mesh: 10mm
Honeycomb grid STL file, 250x250mm, mesh: 10mm
Square grid model as a STL file. The overall size is 250x250 mm, with very large 10 mm cell size for maximum airflow. This grid serves as both a protective guard and a ventilation panel.
Parameter Value Unit
length or center-to-center 250 mm
width or center-to-center 250 mm
mesh size 10 mm
dual color no
holes no

📦 Model #4414

2 object(s)
- format STL
Round box with lid STL 3D file ⌀ 134 mm - Height: 20 mm, Shell: 2 mm
Round box with lid STL 3D file ⌀ 134 mm - Height: 20 mm, Shell: 2 mm
View of object #0
Get this circular box model in 3D STL format. Its diameter is 134 mm and its total height is 20 mm. The wall thickness is 2 mm. A fillet located at the bottom of the box makes it easier to grip objects.
Parameter Value Unit
external diameter 134 mm
total height 20 mm
wall thickness 2 mm
fit clearance 0.2 mm
inner bottom fillet 1 mm

📦 Model #4497

1 object(s)
- format STL
Tubing adapter STL 3D file ⌀ 32–19 mm (Length: 65 mm)
Tubing adapter STL 3D file ⌀ 32–19 mm (Length: 65 mm)
Tube fitting ⌀32 mm to ⌀19 mm in STL 3D format. Length of this junction is 65 mm. The thickness of the tubes is identical: 2 mm. The larger-diameter tube has a sleeve length of 35 mm, the smaller one of 20 mm. The ends are not rounded.
Parameter Value Unit
side A length 35 mm
side A outer diameter 32 mm
side A thickness 2 mm
side B length 20 mm
side B outer diameter 19 mm
side B thickness 2 mm
transition length 10 mm
axis offset 0 mm
ends fillet no fillet

📦 Model #4476

1 object(s)
- format STL
Tubing adapter STL 3D file ⌀ 40–37 mm (Length: 115 mm)
Tubing adapter STL 3D file ⌀ 40–37 mm (Length: 115 mm)
Tube adapter ⌀40 mm to ⌀37 mm in STL 3D format. Length of this connector is 115 mm. The thickness of the tubes is identical: 5 mm. The larger-diameter tube has a sleeve length of 35 mm, the smaller one of 40 mm. The ends are rounded to facilitate the connection of the two tubes.
Parameter Value Unit
side A length 35 mm
side A outer diameter 40 mm
side A thickness 5 mm
side B length 40 mm
side B outer diameter 37 mm
side B thickness 5 mm
transition length 40 mm
axis offset 0 mm
ends fillet fillet on bo...

📦 Model #3421

1 object(s)
- format STL
Honeycomb grid STL file, center-to-center: 120x120mm, mesh: 10mm - Ø8mm
Honeycomb grid STL file, center-to-center: 120x120mm, mesh: 10mm - Ø8mm
3D square protective honeycomb grid file in STL format. Mounting holes are placed at the four corners (center-to-center 120x120 mm), each with a diameter of Ø8 mm. The overall dimensions reach 136x136 mm, with very large 10 mm cell size for peak ventilation. This grid functions as both a mechanical guard and a ventilation panel.
Parameter Value Unit
length or center-to-center 120 mm
width or center-to-center 120 mm
mesh size 10 mm
dual color no
holes yes
hole diameter 8 mm

📦 Model #1929

1 object(s)
- format STL
Tube adapter STL 3D file ⌀ 94–80 mm (Length: 50 mm)
Tube adapter STL 3D file ⌀ 94–80 mm (Length: 50 mm)
Tube reducer ⌀94 mm to ⌀80 mm in STL 3D format. Final length of this reducer is 50 mm. The thickness of the tubes is identical: 2 mm. The larger-diameter tube has a sleeve length of 20 mm, the smaller one of 20 mm as well. The axes of the tubes are off-center by 5.9 mm. The ends feature an external fillet.
Parameter Value Unit
side A length 20 mm
side A outer diameter 94 mm
side A thickness 2 mm
side B length 20 mm
side B outer diameter 80 mm
side B thickness 2 mm
transition length 10 mm
axis offset 5.9 mm
ends fillet fillet on th...

📦 Model #2195

1 object(s)
- format STL
Box STL 3D file with dimensions 100×80×35 mm
Box STL 3D file with dimensions 100×80×35 mm
This STL file offers a single slot measuring 100×80×35mm. External size are 104×84×37mm. The fillet of 2mm helps with item retrieval inside the box.
Parameter Value Unit
number of rows 1
number of columns 1
compartment length 100 mm
compartment width 80 mm
compartment height 35 mm
wall thickness 2 mm
compartment fillet (radius) 2 mm

📦 Model #1089

1 object(s)
- format STL
Multi-compartment box STL 3D file: 100 compartments of 12×12×80 mm
Multi-compartment box STL 3D file: 100 compartments of 12×12×80 mm
This 3D model in STL format provides 100 cavities measuring 12×12×80mm each. The total dimensions are 142×142×82mm.
Parameter Value Unit
number of rows 10
number of columns 10
compartment length 12 mm
compartment width 12 mm
compartment height 80 mm
wall thickness 2 mm
compartment fillet (radius) 1 mm

📦 Model #816

1 object(s)
- format STL
U-shaped handle STL file 35×100×14 mm (Center-to-center 86 mm)
U-shaped handle STL file 35×100×14 mm (Center-to-center 86 mm)
Download this STL 3D model of a simple U-shaped handle. The overall dimensions are 35×100×14 mm. The handle has a square section and a right-angled transition. The holes are 6 mm diameter with a center-to-center distance of 86 mm.
Parameter Value Unit
width 35 mm
length 100 mm
thickness 14 mm
shape (0:square,1:circle) 0
transition (0:right,1:rounded) 0
fillet radius 0 mm
hole diameter 6 mm

📦 Model #4201

1 object(s)
- format STL
Washer / Flat Gasket STL 3D file ⌀ID: 3.9 mm ⌀OD: 6.9 mm thickness: 4.3 mm
Washer / Flat Gasket STL 3D file ⌀ID: 3.9 mm ⌀OD: 6.9 mm thickness: 4.3 mm
3D model of washer / gasket in STL 3D file format. This part features an inner diameter of ⌀3.9 mm and an outer diameter of ⌀6.9 mm. The total thickness is 4.3 mm. This part has no finish applied.
Parameter Value Unit
inner diameter 3.9 mm
outer diameter 6.9 mm
thickness 4.3 mm
finish none

📦 Model #3057

1 object(s)
- format STL
Right-angle bracket 150×150 mm STL 3D file, thickness 6 mm, hole diameter 6 mm
Right-angle bracket 150×150 mm STL 3D file, thickness 6 mm, hole diameter 6 mm
3D file of a mounting bracket with a central reinforcement in STL format. The dimensions are 150 mm in length, 150 mm in height, 14 mm in width, and 6 mm in thickness. The screw holes are designed with a diameter of 6 mm. Chamfers are applied to the holes to improve the seating of the heads. The central reinforcement bar reduces bending and provides two clearances for screwdriver access. No support is needed to print this bracket, printed flat on the build plate.
Parameter Value Unit
length 150 mm
height 150 mm
width 14 mm
thickness 6 mm
hole diameter 6 mm
chamfer on the holes yes

📦 Model #3502

1 object(s)
- format STL
Protective grid STL 3D file, 60x60mm, mesh: 8mm
Protective grid STL 3D file, 60x60mm, mesh: 8mm
Download this 3D square honeycomb grid model in STL format. The overall size is 60x60 mm, with wide 8 mm cell size for optimal air circulation. This type of grid serves both protection and ventilation roles.
Parameter Value Unit
length or center-to-center 60 mm
width or center-to-center 60 mm
mesh size 8 mm
dual color no
holes no

📦 Model #4503

1 object(s)
- format STL
Tube adapter STL 3D file ⌀ 125–80 mm (Length: 105 mm)
Tube adapter STL 3D file ⌀ 125–80 mm (Length: 105 mm)
Straight tube coupler ⌀125 mm to ⌀80 mm in STL format. Total length of this junction is 105 mm. The thickness of the tubes is identical: 5 mm. The larger-diameter tube has a sleeve length of 35 mm, the smaller one of 40 mm. The ends are raw.
Parameter Value Unit
side A length 35 mm
side A outer diameter 125 mm
side A thickness 5 mm
side B length 40 mm
side B outer diameter 80 mm
side B thickness 5 mm
transition length 30 mm
axis offset 0 mm
ends fillet no fillet

📦 Model #2533

3 object(s)
- format STL
Small parts organizer with 2 drawers 148×20×60 mm STL file, thickness: 2 mm
Small parts organizer with 2 drawers 148×20×60 mm STL file, thickness: 2 mm
View of object #0
3D model of a DIY organizer in STL format. This model features 2 compartments, arranged in 2 rows and 1 columns. Practically speaking, this means 2 rows of 1 compartments. Each compartment comes with an inner space of 148 mm wide, 20 mm high, and 60 mm deep. The wall thickness is 2 mm. The compartments include 2 dividers each, which allows up to 3 sections per compartment and up to 6 sections in total. The global dimensions of the box come to 156.5 x 51 x 66 mm. All the objects in this model were designed to be printable without support.
Parameter Value Unit
number of rows 2
number of columns 1
inner drawer depth 60 mm
inner drawer width 148 mm
inner drawer height 20 mm
wall thickness 2 mm
removable divider two divider ...

📦 Model #2543

2 object(s)
- format STL
Enclosure with screw-mounted lid STL file: 42×40×20 mm (with ventilation on the lid and under the enclosure)
Enclosure with screw-mounted lid STL file: 42×40×20 mm (with ventilation on the lid and under the enclosure)
View of object #0
Download this enclosure with lid in 3D STL format. The dimensions are 42 mm long by 40 mm wide and 20 mm high. The lid measures 10 mm high. Side thickness is 5 mm. This enclosure has significant cooling area on the lid and under the base.
Parameter Value Unit
length 42 mm
width 40 mm
total height 20 mm
lid height 10 mm
wall thickness 5 mm
screw margin 0 mm
fit clearance 0.1 mm
cooling level 10
cooling zone(s) cutouts on b...

📦 Model #3491

1 object(s)
- format STL
Protective grid STL file, center-to-center: 107x107mm, mesh: 10mm - Ø5mm
Protective grid STL file, center-to-center: 107x107mm, mesh: 10mm - Ø5mm
3D square protective honeycomb grid model as a STL file. Mounting holes are placed at the four corners (center-to-center 107x107 mm), each with a diameter of Ø5 mm. The overall dimensions reach 117x117 mm, with very large 10 mm cell size for maximum airflow. This grid serves as both a protective guard and a ventilation panel.
Parameter Value Unit
length or center-to-center 107 mm
width or center-to-center 107 mm
mesh size 10 mm
dual color no
holes yes
hole diameter 5 mm

📦 Model #4187

1 object(s)
- format STL
Protective grid STL file, 280x135mm, mesh: 10mm
Protective grid STL file, 280x135mm, mesh: 10mm
Download this 3D rectangular protective honeycomb grid file in STL format. The overall size is 280x135 mm, with very open 10 mm cell size for maximum airflow. This type of grid provides mechanical protection and ventilation.
Parameter Value Unit
length or center-to-center 280 mm
width or center-to-center 135 mm
mesh size 10 mm
dual color no
holes no

📦 Model #2227

1 object(s)
- format STL
O'ring STL file ID 36 × CS 3.6 mm
O'ring STL file ID 36 × CS 3.6 mm
STL file of O-ring (torus-shaped seal) with ID 36 mm × CS (cross section) 3.6  mm. Final diameter corresponds to 43.2 mm.
Parameter Value Unit
inner diameter (ID) 36 mm
cross section (CS) 3.6 mm

📦 Model #2829

1 object(s)
- format STL
Tubing elbow STL file 90° ⌀OD: 24 mm ⌀ID: 22 mm thickness: 1 mm
Tubing elbow STL file 90° ⌀OD: 24 mm ⌀ID: 22 mm thickness: 1 mm
Model of a tubing elbow with a 90° angle in STL format. This elbow has an external diameter of 24 mm and an internal diameter of 22 mm. This results in a tube thickness of 1 mm.
Parameter Value Unit
outer diameter 24 mm
inner diameter 22 mm
angle 90 °
end fillets no

📦 Model #2390

1 object(s)
- format STL
Round air vent STL 3D file ∅ 115 mm, slat angle: 45°
Round air vent STL 3D file ∅ 115 mm, slat angle: 45°
3D file of a round grille for air circulation in STL format. Its male diameter is 115 mm. The slats have an angle of 45° and a high thickness of 2 mm. This ventilation grille has a collar of 10 mm. The full diameter of this model is 135 mm.
Parameter Value Unit
male diameter 115 mm
slat angle 45 °
slat thickness 2 mm
flange width 10 mm
central reinforcement no

📦 Model #4504

1 object(s)
- format STL
Honeycomb grille STL file, center-to-center: 150x137mm, mesh: 10mm - Ø4mm
Honeycomb grille STL file, center-to-center: 150x137mm, mesh: 10mm - Ø4mm
Honeycomb protective rectangular grid model as a STL file. Mounting holes are placed at the four corners (center-to-center 150x137 mm), each with a diameter of Ø4 mm. The overall dimensions reach 158x145 mm, with extra wide 10 mm cell size for peak ventilation. This type of grid serves both protection and ventilation roles.
Parameter Value Unit
length or center-to-center 150 mm
width or center-to-center 137 mm
mesh size 10 mm
dual color no
holes yes
hole diameter 4 mm

📦 Model #2691

2 object(s)
- format STL
Small parts organizer with 12 drawers 45×50×60 mm STL file, thickness: 3 mm
Small parts organizer with 12 drawers 45×50×60 mm STL file, thickness: 3 mm
View of object #0
Download this model of a sorting cabinet with drawers in STL format. This model features 12 compartments, arranged in 3 rows and 4 columns. Specifically, this means 3 rows of 4 compartments. Each compartment offers a storage volume of 45 mm wide, 50 mm high, and 60 mm deep. The wall thickness is 3 mm, which makes the structure solid. The external dimensions of the structure come to 221 x 172.5 x 69 mm. All the objects in this model were designed to be printed without support.
Parameter Value Unit
number of rows 3
number of columns 4
inner drawer depth 60 mm
inner drawer width 45 mm
inner drawer height 50 mm
wall thickness 3 mm
removable divider none

📦 Model #4475

1 object(s)
- format STL
Tube adapter STL 3D file ⌀ 40–37 mm (Length: 118 mm)
Tube adapter STL 3D file ⌀ 40–37 mm (Length: 118 mm)
Straight tube fitting ⌀40 mm to ⌀37 mm in STL format. Total length of this connector is 118 mm. The thickness of the tubes is identical: 5 mm. The larger-diameter tube has a sleeve length of 38 mm, the smaller one of 40 mm. The ends have a fillet to make tube connection easier.
Parameter Value Unit
side A length 38 mm
side A outer diameter 40 mm
side A thickness 5 mm
side B length 40 mm
side B outer diameter 37 mm
side B thickness 5 mm
transition length 40 mm
axis offset 0 mm
ends fillet fillet on bo...

📦 Model #2941

2 object(s)
- format STL
Small parts organizer with 1 drawer 150×150×150 mm STL file, thickness: 2 mm
Small parts organizer with 1 drawer 150×150×150 mm STL file, thickness: 2 mm
View of object #0
Download this file of a storage organizer in STL format. This model includes 1 drawer, arranged in 1 rows and 1 columns. Specifically, this means 1 rows of 1 drawers. Each drawer provides an inside space of 150 mm wide, 150 mm high, and 150 mm deep. The wall thickness is 2 mm. The total size of the structure come to 158.5 x 156.5 x 156 mm. All the objects in this model are intended to be printed without support generation.
Parameter Value Unit
number of rows 1
number of columns 1
inner drawer depth 150 mm
inner drawer width 150 mm
inner drawer height 150 mm
wall thickness 2 mm
removable divider none

STL: Advantages and Disadvantages for 3D Printing

The STL format is, without question, a cornerstone of 3D printing. This exchange format has established itself as the universal standard for representing 3D models ever since the early days of stereolithography. Its main strength lies in its simplicity: it describes the surface of an object using countless small triangles that form a mesh. This approach, known as tessellation, makes STL 3D files universally compatible with nearly all CAD software and slicers. If you’d like to learn more about this format, check out our article STL: What Is This 3D File Format?.

One of the major advantages of the format lies in this universality: whether you’re using a complex modeling program or a simpler design tool, you can export your 3D models in STL 3D format with near certainty that they’ll be interpreted correctly by your 3D printer. This ease of exchange has played a key role in the widespread adoption of 3D printing, allowing anyone to share and print objects without worrying about software compatibility. Once again, simplicity is its greatest strength.

However, that same simplicity also brings certain limitations. The triangle mesh, while effective for describing geometry, contains no information about colors, textures, or materials. For more advanced projects requiring these details, the STL format starts to show its weaknesses. Additionally, print quality depends directly on the fineness of the tessellation: too few triangles can lead to rough or faceted surfaces, while an overly dense mesh can make the file unnecessarily heavy.

Another notable drawback is the lack of unit management. An STL file doesn’t specify whether dimensions are in millimeters, centimeters, or inches, which can sometimes cause scaling errors when importing into a slicer. Despite these limitations, the STL format remains the go-to standard for converting your 3D models into G-code — the language your printer understands. It continues to be the preferred choice for its robustness and broad compatibility, even as newer formats like 3MF emerge for more specialized needs.

What is parametric modeling?

Parametric modeling is a fundamental approach in computer-aided design (CAD) that reshapes how 3D models are created and managed. Far from being a simple drawing technique, it represents a genuine design philosophy where objects are defined not by fixed shapes, but by variables and intelligent relationships.

This method makes it possible to modify the length, width, or diameter of a part and have the entire design adapt automatically, without the need to redraw everything. At the core of the process are parameters—numerical values (length, angle, thickness, etc.)—linked together through constraints and formulas. For instance, the diameter of a hole can be defined as half the width of a plate; if the width changes, the hole’s diameter instantly adjusts, ensuring the consistency of the design. This interdependence makes 3D models flexible and responsive to changes. One of the main advantages of parametric modeling lies in its ability to simplify customization and enable rapid iteration of designs.

Whether through modeling software such as Fusion 360 or FreeCAD, or through code-based libraries like build123d, this approach allows effortless exploration of a wide range of variations. Such flexibility is especially valuable across multiple fields—from mechanical engineering and architecture to consumer product design. It saves considerable time, reduces errors, and improves the performance of parts.

By defining design intent from the start through these parameters and constraints, the model preserves its integrity and functionality even after numerous modifications. It is a powerful way to transform an idea into a tangible object, ready to adapt to new situations.