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

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Star-pattern connector 10 ways STL file – Outer diameter 30 mm, wall thickness 3 mm

Multi-compartment box STL file: 3 compartments of 45×45×45 mm

Rectangular pipe adapter STL 3D file 110x110 mm to 80x80 mm – transition: 20 mm

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

Rectangular-base box with lid STL 3D model – 100×60×20 mm, wall thickness 2 mm

Tube adapter STL 3D file ⌀ 100–16 mm (Length: 110 mm)

Rectangular box with lid STL 3D file – 200×20×20 mm, wall thickness 2 mm

Enclosure with screw-mounted lid STL file: 90×50×40 mm (with ventilation on the lid)

Round-to-Rectangular Tube Adapter STL file ⌀100 mm to 50×50 mm, thickness 2 mm

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

Corner bracket 100×100 mm STL file, thickness 5 mm, hole diameter 5 mm 📦 #2942

1 object(s) - format STL

View of object #0

Latest user-generated 3D models

Rectangular box with lid STL file – 180×63×61 mm, wall thickness 3 mm 📦 #10147

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 #3550

1 object(s)

- format STL

O-ring STL file ID 55 × CS 10 mm

3D model in STL format of O-ring (torus-shaped seal) with Internal diameter (ID) 55 mm × section thickness 10 mm. Outer diameter (OD) resulting is therefore 75 mm.

Parameter	Value	Unit
inner diameter (ID)	55	mm
cross section (CS)	10	mm

📦 Model #4066

2 object(s)

- format STL

Round box with lid STL file ⌀ 47 mm - Height: 30 mm, Shell: 2 mm

Get this round organizing box in STL format. Its diameter is 47 mm and its height is 30 mm. The wall thickness is 2 mm. A pronounced fillet located at the bottom of the box makes it easier to grip objects present inside.

Parameter	Value	Unit
external diameter	47	mm
total height	30	mm
wall thickness	2	mm
fit clearance	1	mm
inner bottom fillet	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

📦 Model #1818

1 object(s)

- format STL

Washer / Flat Gasket STL 3D file ⌀ID: 57 mm ⌀OD: 71 mm thickness: 5 mm + fillets

Download this 3D file of washer / flat gasket in STL 3D file format. This model has an internal diameter of ⌀57 mm and an external diameter of ⌀71 mm. The thickness is 5 mm. Fillets are applied on both the internal diameter and the external diameter, each with a value of 3.4 mm.

Parameter	Value	Unit
inner diameter	57	mm
outer diameter	71	mm
thickness	5	mm
finish	fillet
finish position	inner + oute...
sides	one side
finish value	3.4	mm

📦 Model #4342

1 object(s)

- format STL

Oval duct transition fitting STL file 100.1x100 mm to 80x40 mm – transition: 20 mm

STL 3D file for an oval duct adapter. On side A, the internal cross-section is 100.1x100 mm (nearly circular), whereas on side B it is 80x40 mm (oval). 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. Wall thickness is generous (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	100.1	mm
side A internal height	100	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

📦 Model #2497

1 object(s)

- format STL

Pot STL 3D file, inner: base Ø40 mm, top Ø200 mm, height 40 mm - wall thickness 1 mm

Download this 3D model of a bowl in STL format. This model can be used for sorting small parts in a workshop or on a desk. The shape is very flared, with a internal height of 40 mm, a internal diameter at the top of 200 mm, and a internal diameter at the bottom of 40 mm. The bowl height is 41 mm.

Parameter	Value	Unit
inner bottom diameter	40	mm
inner top diameter	200	mm
inner height	40	mm
wall thickness	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

📦 Model #1917

1 object(s)

- format STL

Round-to-Rectangular Tube Adapter STL file ⌀77 mm to 50×10 mm, thickness 2 mm + offset

3D file in STL format of a round-to-rectangular adapter with an external diameter of ⌀77 mm and a rectangular section with internal dimensions 50×10 mm. The wall thickness is 2 mm and the total length is 60 mm. The adapter has an offset of 17.5 mm along the Z axis. Chamfers are applied on the outside of the cylindrical end and on the inside of the rectangular end to ease insertion.

Parameter	Value	Unit
cylinder outer diameter	77	mm
cylinder inlet length	15	mm
rectangle internal length	50	mm
rectangle internal height	10	mm
rectangle inlet length	10	mm
offset Z	17.5	mm
offset Y	0	mm
total length	60	mm
thickness	2	mm
chamfer	chamfers on ...

📦 Model #4459

1 object(s)

- format STL

Honeycomb grille STL file, center-to-center: 245x245mm, mesh: 8mm - Ø4mm

3D square protective honeycomb grid model in STL format. Mounting holes are placed at the four corners (center-to-center 245x245 mm), each with a diameter of Ø4 mm. The overall dimensions reach 253x253 mm, with large 8 mm cell size to maximize airflow. This grid functions as both a mechanical guard and a ventilation panel.

Parameter	Value	Unit
length or center-to-center	245	mm
width or center-to-center	245	mm
mesh size	8	mm
dual color	no
holes	yes
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

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 #1781

1 object(s)

- format STL

Multi-compartment box STL file: 8 compartments of 20×20×20 mm

This STL file provides 8 cavities measuring 20×20×20mm each. The total dimensions of the box are 46×90×22mm. A 2mm fillet applied to each compartment help with item retrieval stored in the compartments.

Parameter	Value	Unit
number of rows	4
number of columns	2
compartment length	20	mm
compartment width	20	mm
compartment height	20	mm
wall thickness	2	mm
compartment fillet (radius)	2	mm

📦 Model #1220

1 object(s)

- format STL

Tube adapter STL file ⌀ 80–75 mm (Length: 100 mm)

Inline tube coupler ⌀80 mm to ⌀75 mm in STL format. Total length of this adapter is 100 mm. The thickness of the tubes is identical: 2.5 mm. The larger-diameter tube has a sleeve length of 45 mm, the smaller one of 45 mm as well. The axes of the tubes are offset by 2.4 mm. The ends have a fillet on the outside to make tube connection easier.

Parameter	Value	Unit
side A length	45	mm
side A outer diameter	80	mm
side A thickness	2.5	mm
side B length	45	mm
side B outer diameter	75	mm
side B thickness	2.5	mm
transition length	10	mm
axis offset	2.4	mm
ends fillet	fillet on th...

📦 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 #2033

1 object(s)

- format STL

Tube adapter STL 3D file ⌀ 35–34 mm (Length: 100 mm)

Tube reducer ⌀35 mm to ⌀34 mm in STL 3D format. Final length of this adapter is 100 mm. The thickness of the tubes is identical: 3 mm. The larger-diameter tube has a sleeve length of 40 mm, the smaller one of 40 mm as well. The ends feature a fillet.

Parameter	Value	Unit
side A length	40	mm
side A outer diameter	35	mm
side A thickness	3	mm
side B length	40	mm
side B outer diameter	34	mm
side B thickness	3	mm
transition length	20	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

📦 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 #4144

1 object(s)

- format STL

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 #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 #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 #4425

1 object(s)

- format STL

Protective grid STL file, center-to-center: 90x64mm, mesh: 3mm - Ø4mm

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 #4073

1 object(s)

- format STL

Washer / Flat Gasket STL file ⌀ID: 19.8 mm ⌀OD: 22.5 mm thickness: 10 mm

Download this 3D file of gasket / washer in STL 3D file format. This model features an inner diameter of ⌀19.8 mm and an outer diameter of ⌀22.5 mm. The total thickness is 10 mm. No finish is available.

Parameter	Value	Unit
inner diameter	19.8	mm
outer diameter	22.5	mm
thickness	10	mm
finish	none

📦 Model #2204

1 object(s)

- format STL

Multi-compartment box STL file: 14 compartments of 100×30×30 mm

This STL 3D model features 14 sections measuring 100×30×30mm each. The total dimensions are 716×66×32mm. Fillets of 5mm applied to all compartments make it easier to grasp items stored in slots.

Parameter	Value	Unit
number of rows	2
number of columns	7
compartment length	100	mm
compartment width	30	mm
compartment height	30	mm
wall thickness	2	mm
compartment fillet (radius)	5	mm

📦 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

📦 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 #4072

1 object(s)

- format STL

Round-to-Rectangular Tube Adapter STL file ⌀150 mm to 200×80 mm, thickness 3 mm

3D model in STL format of a round-to-rectangular adapter with an external diameter of ⌀150 mm and a rectangular section with internal dimensions 200×80 mm. The wall thickness is 3 mm and the overall length is 200 mm.

Parameter	Value	Unit
cylinder outer diameter	150	mm
cylinder inlet length	50	mm
rectangle internal length	200	mm
rectangle internal height	80	mm
rectangle inlet length	50	mm
offset Z	0	mm
offset Y	0	mm
total length	200	mm
thickness	3	mm
chamfer	no chamfer

📦 Model #1230

1 object(s)

- format STL

Tube adapter STL file ⌀ 64–49 mm (Length: 65 mm)

Tube reducer ⌀64 mm to ⌀49 mm in STL format. Length of this coupler is 65 mm. The larger-diameter tube has a thickness of 4 mm and a length of 25 mm. The smaller-diameter tube has a thickness of 3 mm and a length of 25 mm as well. The ends have no fillet.

Parameter	Value	Unit
side A length	25	mm
side A outer diameter	64	mm
side A thickness	4	mm
side B length	25	mm
side B outer diameter	49	mm
side B thickness	3	mm
transition length	15	mm
axis offset	0	mm
ends fillet	no fillet

📦 Model #3882

1 object(s)

- format STL

Tube adapter STL 3D file ⌀ 55–35 mm (Length: 50 mm)

Straight sleeve ⌀55 mm to ⌀35 mm in STL format. Final length of this sleeve is 50 mm. The larger-diameter tube has a thickness of 4 mm and a sleeve length of 25 mm. The smaller-diameter tube has a thickness of 3 mm and a length of 20 mm. The ends are rounded on the outside to make tube connection easier.

Parameter	Value	Unit
side A length	25	mm
side A outer diameter	55	mm
side A thickness	4	mm
side B length	20	mm
side B outer diameter	35	mm
side B thickness	3	mm
transition length	5	mm
axis offset	0	mm
ends fillet	fillet on th...

📦 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 #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...

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.