Free custom STL files and 3D models for 3D printers

Can’t find the model? Generate it! Trusted by makers worldwide.

Latest user-generated 3D models

From the Blog

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.

A selection of custom 3D models

Model in STL format of a round-to-rectangular adapter with an external diameter of ⌀20.3 mm and a rectangular section with inner dimensions 20×10 mm. The shell thickness is 2 mm and the overall length is 75 mm. The adapter has an offset of 5 mm along the Y 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 20.3 mm
cylinder inlet length 25 mm
rectangle internal length 20 mm
rectangle internal height 10 mm
rectangle inlet length 30 mm
offset Z 0 mm
offset Y 5 mm
total length 75 mm
thickness 2 mm
chamfer chamfers on ...
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
Color-coded compartment box STL 3D file: 16 compartments of 25×25×25 mm
View of object #0
This 3D model in STL format of a storage box with color markers includes 16 slots measuring 25×25×25 mm each. Overall dimensions of the box are 62×236×29 mm. Fillets of 2 mm applied to each compartment, make it easier to grasp items stored in the slots. The walls are particularly robust.
Parameter Value Unit
number of rows 8
number of columns 2
compartment length 25 mm
compartment width 25 mm
compartment height 25 mm
wall thickness 4 mm
compartment fillet (radius) 2 mm
row colors ABABABAB
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 #1561

1 object(s)
- format STL
O-ring STL 3D file ID 15 × CS 1.5 mm
STL model of sealing ring with Inner diameter 15 mm / thickness 1.5  mm. The outer diameter resulting is therefore 18 mm.
Parameter Value Unit
inner diameter (ID) 15 mm
cross section (CS) 1.5 mm
This storage box design features 9 compartments measuring 16×26×10mm each. Overall dimensions are 56×86×12mm. The cavities are not equipped with any fillet.
Parameter Value Unit
number of rows 3
number of columns 3
compartment length 16 mm
compartment width 26 mm
compartment height 10 mm
wall thickness 2 mm
compartment fillet (radius) 0 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
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 #4475

1 object(s)
- format STL
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...
Round box with lid STL 3D file ⌀ 100 mm - Height: 200 mm, Shell: 3 mm
View of object #0
Get this cylindrical storage box in STL format. Its diameter is 100 mm and its total height is 200 mm. The walls have a thickness of 3 mm. A fillet located at the bottom of the box makes it easier to grab stored objects inside.
Parameter Value Unit
external diameter 100 mm
total height 200 mm
wall thickness 3 mm
fit clearance 0.2 mm
inner bottom fillet 1 mm

📦 Model #2390

1 object(s)
- format STL
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
Download this rectangular grid model in STL format. Mounting holes are placed at the four corners (center-to-center 90x64 mm), each with a diameter of Ø4 mm. The overall dimensions reach 98x72 mm, with extra fine 3 mm cell size for maximum protection. This type of grid serves both protection and ventilation roles.
Parameter Value Unit
length or center-to-center 90 mm
width or center-to-center 64 mm
mesh size 3 mm
dual color no
holes yes
hole diameter 4 mm

📦 Model #4503

1 object(s)
- format STL
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
Download this 3D file in STL format of a round-to-rectangular tube adapter with an outer diameter of ⌀155 mm and a rectangular section with inner dimensions 151×71 mm. The wall thickness is 2 mm and the total length is 100 mm.
Parameter Value Unit
cylinder outer diameter 155 mm
cylinder inlet length 25 mm
rectangle internal length 151 mm
rectangle internal height 71 mm
rectangle inlet length 25 mm
offset Z 0 mm
offset Y 0 mm
total length 100 mm
thickness 2 mm
chamfer no chamfer

📦 Model #1483

1 object(s)
- format STL
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
Square protective honeycomb grid model as a STL file. Mounting holes are placed at the four corners (center-to-center 65x65 mm), each with a diameter of Ø4 mm. The overall dimensions reach 73x73 mm, with regular 5 mm cell size for balanced airflow and protection. This grid provides both mechanical protection and airflow.
Parameter Value Unit
length or center-to-center 65 mm
width or center-to-center 65 mm
mesh size 5 mm
dual color no
holes yes
hole diameter 4 mm

📦 Model #4497

1 object(s)
- format STL
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
Download this 3D file in STL format of a round-to-rectangular adapter with an outer diameter of ⌀80 mm and a rectangular section with inner dimensions 105×50 mm. The wall thickness is 2 mm and the total length is 150 mm.
Parameter Value Unit
cylinder outer diameter 80 mm
cylinder inlet length 50 mm
rectangle internal length 105 mm
rectangle internal height 50 mm
rectangle inlet length 50 mm
offset Z 0 mm
offset Y 0 mm
total length 150 mm
thickness 2 mm
chamfer no chamfer

📦 Model #4476

1 object(s)
- format STL
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...
Protective grid STL file, center-to-center: 105x105mm, mesh: 4mm - Ø3mm
View of object #0
Square protective honeycomb grid model in STL format. Mounting holes are placed at the four corners (center-to-center 105x105 mm), each with a diameter of Ø3 mm. The overall dimensions reach 111x111 mm, with regular 4 mm cell size for versatile use. A secondary color frame emphasizes the border. This grid functions as both a mechanical guard and a ventilation panel.
Parameter Value Unit
length or center-to-center 105 mm
width or center-to-center 105 mm
mesh size 4 mm
dual color yes
holes yes
hole diameter 3 mm

📦 Model #3502

1 object(s)
- format STL
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
Small parts organizer with 1 drawer 30×20×50 mm STL 3D file, thickness: 2 mm
View of object #0
3D file of a multi-drawer unit in STL format. This model includes 1 drawer, arranged in 1 rows and 1 columns. Practically speaking, this means 1 rows of 1 drawers. Each drawer offers a storage volume of 30 mm wide, 20 mm high, and 50 mm deep. The wall thickness is 2 mm. The external dimensions of the structure measure 38.5 x 26.5 x 56 mm. All the objects in this model are intended to be printed without support.
Parameter Value Unit
number of rows 1
number of columns 1
inner drawer depth 50 mm
inner drawer width 30 mm
inner drawer height 20 mm
wall thickness 2 mm
removable divider none

📦 Model #4396

1 object(s)
- format STL
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 #2774

1 object(s)
- format STL
Tubing adapter STL 3D file ⌀ 102–60 mm (Length: 253 mm)
Straight tubing adapter ⌀102 mm to ⌀60 mm in STL format. Length of this reducer is 253 mm. The thickness of the tubes is identical: 4.5 mm. The larger-diameter tube has a length of 89 mm, the smaller one of 88 mm. The ends are raw.
Parameter Value Unit
side A length 89 mm
side A outer diameter 102 mm
side A thickness 4.5 mm
side B length 88 mm
side B outer diameter 60 mm
side B thickness 4.5 mm
transition length 76 mm
axis offset 0 mm
ends fillet no fillet

📦 Model #2156

1 object(s)
- format STL
Tube adapter STL file ⌀ 210–20 mm (Length: 160 mm)
Inline tube reducer ⌀210 mm to ⌀20 mm in STL format. Length of this sleeve is 160 mm. The thickness of the tubes is identical: 5 mm. The larger-diameter tube has a sleeve length of 100 mm, the smaller one of 30 mm. The ends are raw.
Parameter Value Unit
side A length 100 mm
side A outer diameter 210 mm
side A thickness 5 mm
side B length 30 mm
side B outer diameter 20 mm
side B thickness 5 mm
transition length 30 mm
axis offset 0 mm
ends fillet no fillet

📦 Model #1162

1 object(s)
- format STL
Tube adapter STL 3D file ⌀ 250–200 mm (Length: 140 mm)
Tube fitting ⌀250 mm to ⌀200 mm in STL 3D format. Total length of this sleeve is 140 mm. The thickness of the tubes is identical: 5 mm. The larger-diameter tube has a length of 60 mm, the smaller one of 50 mm. The ends have a fillet on the outside to facilitate the connection of the two tubes.
Parameter Value Unit
side A length 60 mm
side A outer diameter 250 mm
side A thickness 5 mm
side B length 50 mm
side B outer diameter 200 mm
side B thickness 5 mm
transition length 30 mm
axis offset 0 mm
ends fillet fillet on th...
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 in STL format of a round-to-rectangular adapter with an external diameter of ⌀20 mm and a rectangular section with inner dimensions 26×26 mm. The shell thickness is 2 mm and the total length is 90 mm.
Parameter Value Unit
cylinder outer diameter 20 mm
cylinder inlet length 30 mm
rectangle internal length 26 mm
rectangle internal height 26 mm
rectangle inlet length 40 mm
offset Z 0 mm
offset Y 0 mm
total length 90 mm
thickness 2 mm
chamfer no chamfer
Small parts organizer with 5 drawers 65×25×25 mm STL 3D file, thickness: 2 mm
View of object #0
Download this 3D model of a storage organizer in STL format. This model contains 5 boxes, arranged in 5 rows and 1 columns. In detail, this means 5 rows of 1 boxes. Each box comes with an inner space of 65 mm wide, 25 mm high, and 25 mm deep. The wall thickness is 2 mm. The boxes include 1 divider each, which allows up to 2 sections per box and up to 10 compartments in total. The global dimensions of the box are 73.5 x 149.5 x 31 mm. All the objects in this model were designed to be printable without support generation.
Parameter Value Unit
number of rows 5
number of columns 1
inner drawer depth 25 mm
inner drawer width 65 mm
inner drawer height 25 mm
wall thickness 2 mm
removable divider one divider ...
Download this 3D square grid model in STL format. Mounting holes are placed at the four corners (center-to-center 250x250 mm), each with a diameter of Ø6 mm. The overall dimensions reach 262x262 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 250 mm
width or center-to-center 250 mm
mesh size 10 mm
dual color no
holes yes
hole diameter 6 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.