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

Download this 3D model in STL format of a round-to-rectangular tube adapter with an outer diameter of ⌀50 mm and a rectangular section with inner dimensions 32×32 mm. The wall thickness is 2 mm and the overall length is 100 mm.
Parameter Value Unit
cylinder outer diameter 50 mm
cylinder inlet length 25 mm
rectangle internal length 32 mm
rectangle internal height 32 mm
rectangle inlet length 15 mm
offset Z 0 mm
offset Y 0 mm
total length 100 mm
thickness 2 mm
chamfer no chamfer
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 #3849

1 object(s)
- format STL
Tube adapter STL file ⌀ 250–50 mm (Length: 80 mm)
Straight tube connector ⌀250 mm to ⌀50 mm in STL 3D format. Final length of this coupler is 80 mm. The larger-diameter tube has a thickness of 5 mm and a length of 30 mm. The smaller-diameter tube has a thickness of 3 mm and a length of 30 mm as well. The ends are raw.
Parameter Value Unit
side A length 30 mm
side A outer diameter 250 mm
side A thickness 5 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
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 #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 #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...

📦 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
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 design of a round grille for ventilation in STL format. Its male diameter is 145 mm. The slats have a slight angle of 10° and a high thickness of 2 mm. A vertical reinforcement reinforces the whole structure. This 3D vent grille has a flange of 10 mm. The overall diameter of the model is 165 mm.
Parameter Value Unit
male diameter 145 mm
slat angle 10 °
slat thickness 2 mm
flange width 10 mm
central reinforcement yes
File in STL format of a round-to-rectangular adapter with an outer diameter of ⌀30.5 mm and a rectangular section with internal dimensions 27×15 mm. The shell thickness is 2 mm and the total length is 50 mm.
Parameter Value Unit
cylinder outer diameter 30.5 mm
cylinder inlet length 20 mm
rectangle internal length 27 mm
rectangle internal height 15 mm
rectangle inlet length 8 mm
offset Z 0 mm
offset Y 0 mm
total length 50 mm
thickness 2 mm
chamfer no chamfer

📦 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...
Download this file in STL format of a round-to-rectangular tube adapter with an outer diameter of ⌀95 mm and a rectangular section with internal dimensions 120×148.5 mm. The shell thickness is 2 mm and the overall length is 100 mm.
Parameter Value Unit
cylinder outer diameter 95 mm
cylinder inlet length 50 mm
rectangle internal length 120 mm
rectangle internal height 148.5 mm
rectangle inlet length 5 mm
offset Z 0 mm
offset Y 0 mm
total length 100 mm
thickness 2 mm
chamfer no chamfer
Design of a round grille for air circulation in STL format. Its insertion diameter is 90 mm. The slats have an angle of 35° and a high thickness of 2.4 mm. A centered vertical reinforcement strengthens the whole structure. This aeration grille features a prominent flange of 18 mm. The total diameter of the model is 126 mm.
Parameter Value Unit
male diameter 90 mm
slat angle 35 °
slat thickness 2.4 mm
flange width 18 mm
central reinforcement yes

📦 Model #4184

1 object(s)
- format STL
Tubing adapter STL file ⌀ 78–65 mm (Length: 70 mm)
Diameter adapter ⌀78 mm to ⌀65 mm in STL 3D format. Length of this reducer is 70 mm. The thickness of the tubes is identical: 2 mm. The larger-diameter tube has a length of 30 mm, the smaller one of 20 mm. The ends are rounded to facilitate the connection of the two tubes.
Parameter Value Unit
side A length 30 mm
side A outer diameter 78 mm
side A thickness 2 mm
side B length 20 mm
side B outer diameter 65 mm
side B thickness 2 mm
transition length 20 mm
axis offset 0 mm
ends fillet fillet on bo...
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 #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 STL file of a U-shaped furniture handle. The external dimensions are 50×140×10 mm. The handle has a round profile combined with a right-angled transition. The mounting holes are 6 mm diameter with a center-to-center distance of 130 mm.
Parameter Value Unit
width 50 mm
length 140 mm
thickness 10 mm
shape (0:square,1:circle) 1
transition (0:right,1:rounded) 0
fillet radius 0 mm
hole diameter 6 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
File of a container in STL format. This container can be used for storing small parts in a workshop or on a desk. The sides are vertical, providing a constant inner volume, with a inner height of 77 mm and an identical inner diameter at the top and bottom of 109 mm. The overall height of the bowl is 79 mm.
Parameter Value Unit
inner bottom diameter 109 mm
inner top diameter 109 mm
inner height 77 mm
wall thickness 2 mm
3D file in STL format of a round-to-rectangular tube adapter with an outer diameter of ⌀50 mm and a rectangular section with inner dimensions 45×35 mm. The wall thickness is 2 mm and the overall length is 50 mm. A chamfer is present on the outside of the cylindrical end.
Parameter Value Unit
cylinder outer diameter 50 mm
cylinder inlet length 10 mm
rectangle internal length 45 mm
rectangle internal height 35 mm
rectangle inlet length 7 mm
offset Z 0 mm
offset Y 0 mm
total length 50 mm
thickness 2 mm
chamfer chamfer on t...

📦 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
File of a round air vent for air circulation in STL format. Its insertion diameter measures 115 mm. The slats have an angle of 45° and a high thickness of 2 mm. A central reinforcement secures the slats. This vent grille has a flange of 10 mm. The overall diameter of the model is 135 mm.
Parameter Value Unit
male diameter 115 mm
slat angle 45 °
slat thickness 2 mm
flange width 10 mm
central reinforcement yes
3D STL model of a ways distribution manifold with 3 ways, ready to use in your projects. The connector has a Y-shaped layout with 3 ways, spaced 120° apart around the center axis. The connector is designed for tubes with a 24 mm outer diameter and a 20 mm inner diameter. The wall is thin, with a thickness of 2 mm. The ends are left without fillets, with raw inner and outer edges. It could be used to branch off flexible ducts, hoses, or rigid pipes in custom layouts.
Parameter Value Unit
number of ports 3
outer diameter 24 mm
inner diameter 20 mm
end fillets none

📦 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
3D model of a pot in STL format. This bowl can be used for sorting small parts in a workshop or on a desk. The sides are vertical, providing a constant inner volume, with a inner height of 185 mm and an identical inner diameter at the top and bottom of 70 mm. The wall is particularly sturdy. The height is 189 mm.
Parameter Value Unit
inner bottom diameter 70 mm
inner top diameter 70 mm
inner height 185 mm
wall thickness 4 mm
Model of a corner bracket reinforced in STL format. The dimensions are 200 mm in length, 200 mm in height, 28 mm in width, and 6 mm in thickness. The mounting holes have a diameter of 5 mm. Chamfers are done to the holes to improve the seating of the heads. The reinforcing bar enhances mechanical strength and includes two clearances for screwdriver access. This bracket prints without support, printed flat on the build plate.
Parameter Value Unit
length 200 mm
height 200 mm
width 28 mm
thickness 6 mm
hole diameter 5 mm
chamfer on the holes yes
Small parts organizer with 4 drawers 50×20×50 mm STL file, thickness: 2 mm
View of object #0
3D model of a multi-drawer box in STL format. This model features 4 drawers, arranged in 2 rows and 2 columns. In detail, this means 2 rows of 2 drawers. Each drawer provides an inside space of 50 mm wide, 20 mm high, and 50 mm deep. The wall thickness is 2 mm. The total size of the structure are 115 x 51 x 56 mm. All the objects in this model were designed to be printable without support generation.
Parameter Value Unit
number of rows 2
number of columns 2
inner drawer depth 50 mm
inner drawer width 50 mm
inner drawer height 20 mm
wall thickness 2 mm
removable divider 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
Download this model of a U-shaped handle. The external dimensions are 50×100×20 mm. This handle has a square profile combined with a right-angled transition. A fillet produces a more pleasant grip. The holes are 4 mm diameter with a center-to-center distance of 80 mm.
Parameter Value Unit
width 50 mm
length 100 mm
thickness 20 mm
shape (0:square,1:circle) 0
transition (0:right,1:rounded) 0
fillet radius 1 mm
hole diameter 4 mm
Oval pipe adapter provided as a STL 3D file. The internal cross-section on side A is 100x70 mm, while on side B it is 80x40 mm. You get a sleeve of 5 mm on side A and 10 mm on side B. The transition section is 20 mm long, for a final overall length of 35 mm. The shell is relatively thick, with a wall thickness of 4 mm. External chamfers are added at the ends to make it easier to insert the adapter into ducts or hoses.
Parameter Value Unit
side A internal width 100 mm
side A internal height 70 mm
sleeve length on side A 5 mm
side B internal width 80 mm
side B internal height 40 mm
sleeve length on side B 10 mm
thickness 4 mm
transition length 20 mm
Y offset 0 mm
Z offset 0 mm
end chamfers outside

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.