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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 #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 #3241

1 object(s)
- format STL
Box STL 3D file with dimensions 100×100×4 mm
Box STL 3D file with dimensions 100×100×4 mm
This 3D model in STL format features a single slot measuring 100×100×4mm. External size are 105×105×6.5mm.
Parameter Value Unit
number of rows 1
number of columns 1
compartment length 100 mm
compartment width 100 mm
compartment height 4 mm
wall thickness 2.5 mm
compartment fillet (radius) 0 mm

📦 Model #2403

1 object(s)
- format STL
Multi-compartment box STL file: 36 compartments of 3×3×75 mm
Multi-compartment box STL file: 36 compartments of 3×3×75 mm
This 3D model in STL format features 36 storage spaces measuring 3×3×75mm each. The total dimensions of the box are 32×32×77mm.
Parameter Value Unit
number of rows 6
number of columns 6
compartment length 3 mm
compartment width 3 mm
compartment height 75 mm
wall thickness 2 mm
compartment fillet (radius) 0.5 mm

📦 Model #1253

2 object(s)
- format STL
Round box with lid STL 3D file ⌀ 70 mm - Height: 150 mm, Shell: 3 mm
Round box with lid STL 3D file ⌀ 70 mm - Height: 150 mm, Shell: 3 mm
View of object #0
Get this round storage box model in STL format. Its diameter is 70 mm and its total height is 150 mm. The wall thickness is 3 mm.
Parameter Value Unit
external diameter 70 mm
total height 150 mm
wall thickness 3 mm
fit clearance 0.1 mm
inner bottom fillet 0 mm

📦 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 #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 #4548

1 object(s)
- format STL
Washer / Flat Gasket STL 3D file ⌀ID: 1 mm ⌀OD: 30 mm thickness: 10 mm
Washer / Flat Gasket STL 3D file ⌀ID: 1 mm ⌀OD: 30 mm thickness: 10 mm
3D model of washer / flat gasket in STL 3D file format. This part features an inner diameter of ⌀1 mm and an outer diameter of ⌀30 mm. The part thickness is 10 mm. No finish is present.
Parameter Value Unit
inner diameter 1 mm
outer diameter 30 mm
thickness 10 mm
finish none

📦 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 #2328

3 object(s)
- format STL
Small parts organizer with 9 drawers 51×45×100 mm STL 3D file, thickness: 4 mm
Small parts organizer with 9 drawers 51×45×100 mm STL 3D file, thickness: 4 mm
View of object #0
Download this 3D model of storage drawers in 3D STL format. This model features 9 boxes, arranged in 3 rows and 3 columns. Specifically, this means 3 rows of 3 boxes. Each box offers a storage volume of 51 mm wide, 45 mm high, and 100 mm deep. The wall thickness is 4 mm, which makes the structure very solid. The boxes include 1 divider each, which allows up to 2 sections per box and up to 18 sections in total. The external dimensions of the structure come to 194.5 x 164.5 x 112 mm. All the objects in this model were designed to be printable without support generation.
Parameter Value Unit
number of rows 3
number of columns 3
inner drawer depth 100 mm
inner drawer width 51 mm
inner drawer height 45 mm
wall thickness 4 mm
removable divider one divider ...

📦 Model #1980

1 object(s)
- format STL
O-ring STL 3D file ID 13 × CS 3 mm
O-ring STL 3D file ID 13 × CS 3 mm
File of rubber ring with ID 13 mm by thickness 3  mm. Outer diameter (OD) resulting corresponds to 19 mm.
Parameter Value Unit
inner diameter (ID) 13 mm
cross section (CS) 3 mm

📦 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 #4144

1 object(s)
- format STL
Honeycomb grille STL 3D file, 195x80mm, mesh: 4mm
Honeycomb grille STL 3D file, 195x80mm, mesh: 4mm
Download this 3D rectangular protective grid file in STL format. The overall size is 195x80 mm, with medium 4 mm cell size for versatile use. This grid provides both mechanical protection and airflow.
Parameter Value Unit
length or center-to-center 195 mm
width or center-to-center 80 mm
mesh size 4 mm
dual color no
holes no

📦 Model #2247

1 object(s)
- format STL
Round-to-Rectangular Tube Adapter STL file ⌀119 mm to 114×79 mm, thickness 3 mm + offset
Round-to-Rectangular Tube Adapter STL file ⌀119 mm to 114×79 mm, thickness 3 mm + offset
Download this model in STL format of a round-to-rectangular adapter with an external diameter of ⌀119 mm and a rectangular section with inner dimensions 114×79 mm. The shell thickness is 3 mm and the overall length is 100 mm. The adapter has an offset of 2 mm along the Y axis and 17.5 mm along the Z axis.
Parameter Value Unit
cylinder outer diameter 119 mm
cylinder inlet length 30 mm
rectangle internal length 114 mm
rectangle internal height 79 mm
rectangle inlet length 30 mm
offset Z 17.5 mm
offset Y 2 mm
total length 100 mm
thickness 3 mm
chamfer no chamfer

📦 Model #2258

1 object(s)
- format STL
Round-to-Rectangular Tube Adapter STL 3D file ⌀76 mm to 160×25 mm, thickness 3 mm + offset
Round-to-Rectangular Tube Adapter STL 3D file ⌀76 mm to 160×25 mm, thickness 3 mm + offset
Model in STL format of a round-to-rectangular tube adapter with an outer diameter of ⌀76 mm and a rectangular section with inner dimensions 160×25 mm. The shell thickness is 3 mm and the overall length is 250 mm. The adapter has an offset of 25 mm along the Y axis and 25 mm along the Z axis.
Parameter Value Unit
cylinder outer diameter 76 mm
cylinder inlet length 50 mm
rectangle internal length 160 mm
rectangle internal height 25 mm
rectangle inlet length 100 mm
offset Z 25 mm
offset Y 25 mm
total length 250 mm
thickness 3 mm
chamfer no chamfer

📦 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 #3031

2 object(s)
- format STL
Round box with lid STL file ⌀ 139 mm - Height: 45 mm, Shell: 4 mm
Round box with lid STL file ⌀ 139 mm - Height: 45 mm, Shell: 4 mm
View of object #0
Get this cylindrical storage box in STL format. Its diameter is 139 mm and its height is 45 mm. The wall thickness is 4 mm.
Parameter Value Unit
external diameter 139 mm
total height 45 mm
wall thickness 4 mm
fit clearance 0.1 mm
inner bottom fillet 0 mm

📦 Model #2582

1 object(s)
- format STL
Round-to-Rectangular Tube Adapter STL 3D file ⌀76 mm to 160×78 mm, thickness 3 mm
Round-to-Rectangular Tube Adapter STL 3D file ⌀76 mm to 160×78 mm, thickness 3 mm
Download this model in STL format of a round-to-rectangular tube adapter with an external diameter of ⌀76 mm and a rectangular section with inner dimensions 160×78 mm. The wall thickness is 3 mm and the overall length is 200 mm.
Parameter Value Unit
cylinder outer diameter 76 mm
cylinder inlet length 76 mm
rectangle internal length 160 mm
rectangle internal height 78 mm
rectangle inlet length 100 mm
offset Z 0 mm
offset Y 0 mm
total length 200 mm
thickness 3 mm
chamfer no chamfer

📦 Model #3742

1 object(s)
- format STL
Clip-on tube support Ø13 mm STL file · Countersunk screw Ø3 mm
Clip-on tube support Ø13 mm STL file · Countersunk screw Ø3 mm
Download this 3D model of a Ø13 mm clip-on pipe support in STL format. The installation is achieved with a countersunk screw Ø3 mm. This clip-on pipe support is built for a stable hold and simple mounting.
Parameter Value Unit
tube diameter 13 mm
hole diameter 3 mm
countersunk screw yes

📦 Model #4298

1 object(s)
- format STL
Tube elbow STL file 90° ⌀OD: 16.9 mm ⌀ID: 14.9 mm thickness: 1 mm
Tube elbow STL file 90° ⌀OD: 16.9 mm ⌀ID: 14.9 mm thickness: 1 mm
3D file of a tubing elbow with a 90° angle in STL format. This pipe elbow features an outer diameter of 16.9 mm and an inner diameter of 14.9 mm. The tube thickness is therefore 1 mm. The ends feature fillets to make it easier to insert.
Parameter Value Unit
outer diameter 16.9 mm
inner diameter 14.9 mm
angle 90 °
end fillets yes

📦 Model #856

1 object(s)
- format STL
U-shaped handle STL 3D file 35×140×10 mm (Center-to-center 130 mm)
U-shaped handle STL 3D file 35×140×10 mm (Center-to-center 130 mm)
Download this STL 3D model of a U-shaped drawer handle. The overall dimensions are 35×140×10 mm. This handle features a square cross-section and a softened transition. The holes are 4 mm diameter with a center-to-center distance of 130 mm.
Parameter Value Unit
width 35 mm
length 140 mm
thickness 10 mm
shape (0:square,1:circle) 0
transition (0:right,1:rounded) 1
fillet radius 0 mm
hole diameter 4 mm

📦 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 #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 #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 #4415

2 object(s)
- format STL
Round box with lid STL file ⌀ 115 mm - Height: 42 mm, Shell: 3 mm
Round box with lid STL file ⌀ 115 mm - Height: 42 mm, Shell: 3 mm
View of object #0
Get this circular organizing box in 3D STL format. Its diameter is 115 mm and its total height is 42 mm. The wall width is 3 mm. A fillet located at the bottom of the box makes it easier to grab objects.
Parameter Value Unit
external diameter 115 mm
total height 42 mm
wall thickness 3 mm
fit clearance 0.2 mm
inner bottom fillet 1 mm

📦 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 #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 #923

1 object(s)
- format STL
U-shaped handle STL file 50×100×14 mm (Center-to-center 86 mm)
U-shaped handle STL file 50×100×14 mm (Center-to-center 86 mm)
Download this STL 3D file of a simple U-shaped handle. The external dimensions are 50×100×14 mm. The handle features a square profile combined with a 90-degree transition. The mounting holes are 5 mm diameter with a center-to-center distance of 86 mm.
Parameter Value Unit
width 50 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 5 mm

📦 Model #1940

1 object(s)
- format STL
Round-to-Rectangular Tube Adapter STL 3D file ⌀45 mm to 150×120 mm, thickness 2 mm + offset
Round-to-Rectangular Tube Adapter STL 3D file ⌀45 mm to 150×120 mm, thickness 2 mm + offset
Download this model in STL format of a round-to-rectangular tube adapter with an external diameter of ⌀45 mm and a rectangular section with internal dimensions 150×120 mm. The wall thickness is 2 mm and the total length is 130 mm. The adapter has an offset of 15 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 45 mm
cylinder inlet length 25 mm
rectangle internal length 150 mm
rectangle internal height 120 mm
rectangle inlet length 60 mm
offset Z 15 mm
offset Y 0 mm
total length 130 mm
thickness 2 mm
chamfer chamfers on ...

📦 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 #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...

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.