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Featured Model of the Day

Pot STL 3D file, inner: base Ø121 mm, top Ø122 mm, height 40 mm - wall thickness 1 mm 📦 #3164

1 object(s) - format STL

gizmo

View of object #0

Latest user-generated 3D models

Rectangular box with lid STL 3D model – 250×75×30 mm, wall thickness 3 mm 📦 #10268

2 object(s) - format STL

gizmo

View of object #0

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 #1628

1 object(s)
- format STL
Round-to-Rectangular Tube Adapter STL file ⌀112 mm to 294×67 mm, thickness 3 mm
Round-to-Rectangular Tube Adapter STL file ⌀112 mm to 294×67 mm, thickness 3 mm
File in STL format of a round-to-rectangular adapter with an external diameter of ⌀112 mm and a rectangular section with inner dimensions 294×67 mm. The wall thickness is 3 mm and the overall length is 150 mm.
Parameter Value Unit
cylinder outer diameter 112 mm
cylinder inlet length 30 mm
rectangle internal length 294 mm
rectangle internal height 67 mm
rectangle inlet length 50 mm
offset Z 0 mm
offset Y 0 mm
total length 150 mm
thickness 3 mm
chamfer no chamfer

📦 Model #3616

1 object(s)
- format STL
Clip-on tube support Ø200 mm STL 3D file · Countersunk screw Ø5 mm
Clip-on tube support Ø200 mm STL 3D file · Countersunk screw Ø5 mm
Download this 3D file of a Ø200 mm custom pipe clip in STL format. The installation is performed by means of a countersunk screw Ø5 mm. This snap-on pipe mount is designed for a firm hold and quick installation.
Parameter Value Unit
tube diameter 200 mm
hole diameter 5 mm
countersunk screw yes

📦 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 #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 #4195

1 object(s)
- format STL
Pipe elbow STL 3D file 90° ⌀OD: 87 mm ⌀ID: 84 mm thickness: 1.5 mm
Pipe elbow STL 3D file 90° ⌀OD: 87 mm ⌀ID: 84 mm thickness: 1.5 mm
3D file of a pipe elbow with a 90° angle in STL format. This pipe elbow has an outer diameter of 87 mm and an inner diameter of 84 mm. This results in a tube thickness of 1.5 mm.
Parameter Value Unit
outer diameter 87 mm
inner diameter 84 mm
angle 90 °
end fillets no

📦 Model #3390

1 object(s)
- format STL
Protective grid STL file, center-to-center: 104x104mm, mesh: 10mm - Ø4mm
Protective grid STL file, center-to-center: 104x104mm, mesh: 10mm - Ø4mm
Honeycomb protective square grid file in STL format. Mounting holes are placed at the four corners (center-to-center 104x104 mm), each with a diameter of Ø4 mm. The overall dimensions reach 112x112 mm, with very open 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 104 mm
width or center-to-center 104 mm
mesh size 10 mm
dual color no
holes yes
hole diameter 4 mm

📦 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 #4014

1 object(s)
- format STL
Round-to-Rectangular Tube Adapter STL file ⌀81 mm to 108×52 mm, thickness 3 mm + offset
Round-to-Rectangular Tube Adapter STL file ⌀81 mm to 108×52 mm, thickness 3 mm + offset
Download this 3D file in STL format of a round-to-rectangular adapter with an external diameter of ⌀81 mm and a rectangular section with internal dimensions 108×52 mm. The shell thickness is 3 mm and the total length is 70 mm. The adapter has an offset of 10 mm along the Y axis and 20 mm along the Z axis.
Parameter Value Unit
cylinder outer diameter 81 mm
cylinder inlet length 15 mm
rectangle internal length 108 mm
rectangle internal height 52 mm
rectangle inlet length 15 mm
offset Z 20 mm
offset Y 10 mm
total length 70 mm
thickness 3 mm
chamfer no chamfer

📦 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 #3166

1 object(s)
- format STL
Shelf bracket 150×100 mm STL 3D file, thickness 10 mm, hole diameter 5 mm
Shelf bracket 150×100 mm STL 3D file, thickness 10 mm, hole diameter 5 mm
3D model of a corner bracket reinforced in STL 3D format. The dimensions are 150 mm in length, 100 mm in height, 20 mm in width, and 10 mm in thickness. The screw holes are designed with a diameter of 5 mm. Chamfers are done to the holes for a cleaner fit of the screws. The central reinforcement bar enhances mechanical strength and provides two passages for fastening. Support generation is not required for printing this bracket, printed flat on the build plate.
Parameter Value Unit
length 150 mm
height 100 mm
width 20 mm
thickness 10 mm
hole diameter 5 mm
chamfer on the holes yes

📦 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 #1239

1 object(s)
- format STL
Tube adapter STL 3D file ⌀ 110–106 mm (Length: 35 mm)
Tube adapter STL 3D file ⌀ 110–106 mm (Length: 35 mm)
Tube adapter ⌀110 mm to ⌀106 mm in STL format. Final length of this junction is 35 mm. The thickness of the tubes is identical: 3 mm. The larger-diameter tube has a length of 20 mm, the smaller one of 10 mm. The ends have no fillet.
Parameter Value Unit
side A length 20 mm
side A outer diameter 110 mm
side A thickness 3 mm
side B length 10 mm
side B outer diameter 106 mm
side B thickness 3 mm
transition length 5 mm
axis offset 0 mm
ends fillet no fillet

📦 Model #2231

1 object(s)
- format STL
Multi-compartment box STL 3D file: 3 compartments of 100×50×85 mm
Multi-compartment box STL 3D file: 3 compartments of 100×50×85 mm
This parametric compartment box provides 3 storage spaces measuring 100×50×85mm each. Overall dimensions of the box are 104×158×87mm. Fillets of 2mm applied to all compartments provide a better grip stored in slots.
Parameter Value Unit
number of rows 3
number of columns 1
compartment length 100 mm
compartment width 50 mm
compartment height 85 mm
wall thickness 2 mm
compartment fillet (radius) 2 mm

📦 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 #4468

2 object(s)
- format STL
Enclosure with screw-mounted lid STL 3D file: 100×85×70 mm
Enclosure with screw-mounted lid STL 3D file: 100×85×70 mm
View of object #0
Download this enclosure model with lid in STL format. The dimensions are 100 mm long by 85 mm wide and 70 mm high. The lid only is 20 mm high. Side thickness is 3 mm. The enclosure does not have cooling.
Parameter Value Unit
length 100 mm
width 85 mm
total height 70 mm
lid height 20 mm
wall thickness 3 mm
screw margin 0 mm
fit clearance 0.1 mm
cooling zone(s) no cutouts

📦 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 #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 #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 #1543

1 object(s)
- format STL
O-ring STL file ID 120 × CS 5 mm
O-ring STL file ID 120 × CS 5 mm
3D file of sealing ring with dimensions Internal diameter (ID) 120 mm by CS 5  mm. Outer diameter (OD) resulting is 130 mm.
Parameter Value Unit
inner diameter (ID) 120 mm
cross section (CS) 5 mm

📦 Model #2054

1 object(s)
- format STL
Round air vent STL 3D file ∅ 71 mm, slat angle: 40° with central reinforcement
Round air vent STL 3D file ∅ 71 mm, slat angle: 40° with central reinforcement
Model of a round air vent for ventilation in STL format. Its insertion diameter measures 71 mm. The slats have an angle of 40° and a high thickness of 2.4 mm. A centered vertical reinforcement reinforces the slats. This 3D aeration grille has a thin flange of 4 mm. The full diameter of the model is 79 mm.
Parameter Value Unit
male diameter 71 mm
slat angle 40 °
slat thickness 2.4 mm
flange width 4 mm
central reinforcement yes

📦 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 #4025

1 object(s)
- format STL
Clip-on tube support Ø248 mm STL file · Countersunk screw Ø4 mm
Clip-on tube support Ø248 mm STL file · Countersunk screw Ø4 mm
Download this 3D model of a Ø248 mm clip-on pipe support in STL format. The fastening is performed using a countersunk screw Ø4 mm. This clip-on pipe holder is intended for a firm hold and simple mounting.
Parameter Value Unit
tube diameter 248 mm
hole diameter 4 mm
countersunk screw yes

📦 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 #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 #4101

1 object(s)
- format STL
Round-to-Rectangular Tube Adapter STL file ⌀108 mm to 154×240 mm, thickness 3 mm + offset
Round-to-Rectangular Tube Adapter STL file ⌀108 mm to 154×240 mm, thickness 3 mm + offset
Download this model in STL format of a round-to-rectangular tube adapter with an outer diameter of ⌀108 mm and a rectangular section with inner dimensions 154×240 mm. The wall thickness is 3 mm and the total length is 240 mm. The adapter has an offset of 70 mm along the Z axis. Chamfers are present on the outside of the cylindrical end and on the inside of the rectangular end.
Parameter Value Unit
cylinder outer diameter 108 mm
cylinder inlet length 20 mm
rectangle internal length 154 mm
rectangle internal height 240 mm
rectangle inlet length 50 mm
offset Z 70 mm
offset Y 0 mm
total length 240 mm
thickness 3 mm
chamfer chamfers on ...

📦 Model #1776

2 object(s)
- format STL
Round box with lid STL file ⌀ 160 mm - Height: 20 mm, Shell: 2 mm
Round box with lid STL file ⌀ 160 mm - Height: 20 mm, Shell: 2 mm
View of object #0
Get this round storage box model in 3D STL format. Its diameter is 160 mm and its 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 160 mm
total height 20 mm
wall thickness 2 mm
fit clearance 0.8 mm
inner bottom fillet 0.1 mm

📦 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 #2032

1 object(s)
- format STL
Round-to-Rectangular Tube Adapter STL file ⌀165 mm to 300×120 mm, thickness 3 mm + offset
Round-to-Rectangular Tube Adapter STL file ⌀165 mm to 300×120 mm, thickness 3 mm + offset
Model in STL format of a round-to-rectangular tube adapter with an external diameter of ⌀165 mm and a rectangular section with inner dimensions 300×120 mm. The shell thickness is 3 mm and the total length is 200 mm. The adapter has an offset of 35 mm along the Z axis. Chamfers are present on the outside of the cylindrical end and on the inside of the rectangular end to ease insertion.
Parameter Value Unit
cylinder outer diameter 165 mm
cylinder inlet length 30 mm
rectangle internal length 300 mm
rectangle internal height 120 mm
rectangle inlet length 40 mm
offset Z 35 mm
offset Y 0 mm
total length 200 mm
thickness 3 mm
chamfer chamfers on ...

📦 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 #3934

1 object(s)
- format STL
O-ring STL file ID 20 × CS 4 mm
O-ring STL file ID 20 × CS 4 mm
3D model of sealing ring with dimensions Internal diameter 20 mm / thickness 4  mm. External diameter (OD) resulting is therefore 28 mm.
Parameter Value Unit
inner diameter (ID) 20 mm
cross section (CS) 4 mm

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.