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

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Rectangular duct adapter STL 3D file 100x20 mm to 80x20 mm – transition: 20 mm

Rectangular-base box with lid STL 3D file – 120×80×50 mm, wall thickness 3 mm

Enclosure with screw-mounted lid STL 3D file: 40×40×20 mm (with ventilation on the lid and under the enclosure)

Pipe elbow STL 3D file 180° ⌀OD: 20 mm ⌀ID: 16 mm thickness: 2 mm

Tube adapter STL file ⌀ 100–51 mm (Length: 160 mm)

Pipe elbow STL 3D file 180° ⌀OD: 18 mm ⌀ID: 16 mm thickness: 1 mm

Multi-tubes fitting 3 tubes STL 3D model – Outer diameter 50 mm, wall thickness 5 mm

Box STL 3D file with dimensions 50×50×60 mm

Round box with lid STL 3D file ⌀ 80 mm - Height: 50 mm, Shell: 3 mm

3 tubes fitting STL file – Outer diameter 24 mm, wall thickness 2 mm

Browse a growing library of free STL files and 3D models — or generate custom parts online to your exact specs.

Featured Model of the Day

Square box with lid STL 3D file – 86×86×61 mm, wall thickness 3 mm 📦 #6958

2 object(s) - format STL

View of object #0

Latest user-generated 3D models

Rectangular box with lid STL 3D file – 140×100×55 mm, wall thickness 4 mm 📦 #10890

2 object(s) - format STL

View of object #0

From the Blog

Why Modeling Strategy Matters in Procedural CAD Modeling

2025-12-14 · 3D Modeling · sylvain

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 #2533

3 object(s)

- format STL

Small parts organizer with 2 drawers 148×20×60 mm STL file, thickness: 2 mm

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 #2106

1 object(s)

- format STL

O-ring STL 3D file ID 13 × CS 1 mm

STL model of rubber ring with ID 13 mm / thickness 1 mm. Final diameter resulting is therefore 15 mm.

Parameter	Value	Unit
inner diameter (ID)	13	mm
cross section (CS)	1	mm

📦 Model #1558

1 object(s)

- format STL

Round air vent STL 3D file ∅ 90 mm, slat angle: 35° with central reinforcement

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 #3116

1 object(s)

- format STL

Tube elbow STL file 90° ⌀OD: 181 mm ⌀ID: 176 mm thickness: 2.5 mm

3D model of an elbow with a 90° angle in STL format. This pipe elbow features an outer diameter of 181 mm and an inner diameter of 176 mm. This results in a tube thickness of 2.5 mm.

Parameter	Value	Unit
outer diameter	181	mm
inner diameter	176	mm
angle	90	°
end fillets	no

📦 Model #4432

2 object(s)

- format STL

Round box with lid STL 3D file ⌀ 125 mm - Height: 40 mm, Shell: 3 mm

Get this cylindrical organizing box model in STL format. Its diameter is 125 mm and its height is 40 mm. The wall thickness is 3 mm.

Parameter	Value	Unit
external diameter	125	mm
total height	40	mm
wall thickness	3	mm
fit clearance	0.1	mm
inner bottom fillet	0	mm

📦 Model #784

1 object(s)

- format STL

Rectangular prism STL file 80×82×30 mm

Download this 3D model of a box as an STL file. The final dimensions are 80×82×30 mm. A small fillet softens all the sides.

Parameter	Value	Unit
length	80	mm
width	82	mm
height	30	mm
fillet radius	2	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

📦 Model #3131

1 object(s)

- format STL

Angle bracket 120×120 mm STL file, thickness 10 mm, hole diameter 5 mm

Download this file of a right-angle bracket with a central reinforcing bar in STL 3D format. The dimensions are 120 mm in length, 120 mm in height, 30 mm in width, and 10 mm in thickness. The mounting holes have a diameter of 5 mm. Chamfers are applied to the holes for a cleaner fit of the screws. The reinforcing bar enhances mechanical strength and includes two openings for screwdriver access. Support generation is not required for printing this bracket, placed flat directly on the build plate.

Parameter	Value	Unit
length	120	mm
height	120	mm
width	30	mm
thickness	10	mm
hole diameter	5	mm
chamfer on the holes	yes

📦 Model #2564

2 object(s)

- format STL

Small parts organizer with 48 drawers 40×35×100 mm STL 3D file, thickness: 2 mm

Download this model of a DIY organizer in 3D STL format. This model includes 48 compartments, arranged in 8 rows and 6 columns. Practically speaking, this means 8 rows of 6 compartments. Each compartment has usable dimensions of 40 mm wide, 35 mm high, and 100 mm deep. The wall thickness is 2 mm. The external dimensions of the structure are 281 x 318 x 106 mm. All the objects in this model are intended to be printed without support generation.

Parameter	Value	Unit
number of rows	8
number of columns	6
inner drawer depth	100	mm
inner drawer width	40	mm
inner drawer height	35	mm
wall thickness	2	mm
removable divider	none

📦 Model #3612

1 object(s)

- format STL

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 #3265

1 object(s)

- format STL

Pot STL file, inner: base Ø84 mm, top Ø84 mm, height 40 mm - wall thickness 3 mm

3D model of a bowl in STL format. This container can be used for storing small parts in a workshop or on a desk. The sides are straight, providing a constant internal volume, with a internal height of 40 mm and an identical internal diameter at the top and bottom of 84 mm. The wall is thickened. The overall height of the bowl is 43 mm.

Parameter	Value	Unit
inner bottom diameter	84	mm
inner top diameter	84	mm
inner height	40	mm
wall thickness	3	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

📦 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

📦 Model #3491

1 object(s)

- format STL

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 #2180

3 object(s)

- format STL

Small parts organizer with 9 drawers 70×40×120 mm STL 3D file, thickness: 2 mm

Download this model of a storage organizer in 3D STL format. This model contains 9 boxes, arranged in 3 rows and 3 columns. Practically speaking, this means 3 rows of 3 boxes. Each box comes with an inner space of 70 mm wide, 40 mm high, and 120 mm deep. The wall thickness is 2 mm. The boxes feature 2 dividers each, which allows up to 3 compartments per box and up to 27 compartments in total. The total size of the box come to 231.5 x 135.5 x 126 mm. All the objects in this model were designed to be printed without support.

Parameter	Value	Unit
number of rows	3
number of columns	3
inner drawer depth	120	mm
inner drawer width	70	mm
inner drawer height	40	mm
wall thickness	2	mm
removable divider	two divider ...

📦 Model #2206

3 object(s)

- format STL

Small parts organizer with 16 drawers 30×30×80 mm STL file, thickness: 2 mm

Model of a multi-drawer box in STL format. This model contains 16 boxes, arranged in 2 rows and 8 columns. In detail, this means 2 rows of 8 boxes. Each box comes with an inner space of 30 mm wide, 30 mm high, and 80 mm deep. The wall thickness is 2 mm. The boxes come with 2 dividers each, which allows up to 3 compartments per box and up to 48 sections in total. The overall dimensions of the structure measure 294 x 71 x 86 mm. All the objects in this model were designed to be printed without support generation.

Parameter	Value	Unit
number of rows	2
number of columns	8
inner drawer depth	80	mm
inner drawer width	30	mm
inner drawer height	30	mm
wall thickness	2	mm
removable divider	two divider ...

📦 Model #1932

1 object(s)

- format STL

Tube adapter STL file ⌀ 240–106 mm (Length: 160 mm)

Straight tube connector ⌀240 mm to ⌀106 mm in STL format. Length of this fitting is 160 mm. The thickness of the tubes is identical: 3 mm. The larger-diameter tube has a length of 70 mm, the smaller one of 70 mm as well. The ends are raw.

Parameter	Value	Unit
side A length	70	mm
side A outer diameter	240	mm
side A thickness	3	mm
side B length	70	mm
side B outer diameter	106	mm
side B thickness	3	mm
transition length	20	mm
axis offset	0	mm
ends fillet	no fillet

📦 Model #3057

1 object(s)

- format STL

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 #2516

1 object(s)

- format STL

L-bracket 230×110 mm STL file, thickness 8 mm, hole diameter 6 mm

Download this model of a support bracket with a central reinforcement in STL format. The dimensions are 230 mm in length, 110 mm in height, 50 mm in width, and 8 mm in thickness. The drill holes have a diameter of 6 mm. Chamfers are done to the holes for a cleaner fit of the screws. The reinforcing bar improves rigidity and includes two passages for screwdriver access. Support generation is not required for printing this bracket, printed flat on the build plate.

Parameter	Value	Unit
length	230	mm
height	110	mm
width	50	mm
thickness	8	mm
hole diameter	6	mm
chamfer on the holes	yes

📦 Model #3421

1 object(s)

- format STL

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 #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

📦 Model #840

1 object(s)

- format STL

U-shaped handle STL 3D file 35×100×20 mm (Center-to-center 80 mm)

Download this STL model of a U-shaped handle. The external dimensions are 35×100×20 mm. The handle features a square cross-section and a smooth transition. The bores are 6 mm diameter with a center-to-center distance of 80 mm.

Parameter	Value	Unit
width	35	mm
length	100	mm
thickness	20	mm
shape (0:square,1:circle)	0
transition (0:right,1:rounded)	1
fillet radius	0	mm
hole diameter	6	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 #1977

1 object(s)

- format STL

Round-to-Rectangular Tube Adapter STL 3D file ⌀100 mm to 135×75 mm, thickness 2 mm + offset

Download this model in STL format of a round-to-rectangular adapter with an external diameter of ⌀100 mm and a rectangular section with inner dimensions 135×75 mm. The shell thickness is 2 mm and the overall length is 160 mm. The adapter has an offset of 30 mm along the Z axis.

Parameter	Value	Unit
cylinder outer diameter	100	mm
cylinder inlet length	35	mm
rectangle internal length	135	mm
rectangle internal height	75	mm
rectangle inlet length	60	mm
offset Z	30	mm
offset Y	0	mm
total length	160	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...

📦 Model #1772

1 object(s)

- format STL

Round-to-Rectangular Tube Adapter STL file ⌀80 mm to 105×50 mm, thickness 2 mm

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 #4201

1 object(s)

- format STL

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 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 #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...

📦 Model #4414

2 object(s)

- format STL

Round box with lid STL 3D file ⌀ 134 mm - Height: 20 mm, Shell: 2 mm

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

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.