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

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

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

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

Tube adapter STL 3D file ⌀ 80–50 mm (Length: 80 mm)

Small parts organizer with 25 drawers 40×30×50 mm STL 3D file, thickness: 2 mm

Tube STL file OD 24 mm, ID 20 mm, length 100 mm

Tube STL file OD 56 mm, ID 50 mm, length 30 mm

Oval hose adapter STL file 60x20 mm to 60x20 mm – transition: 140 mm

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

Oval duct transition adapter STL file 80.1x80 mm to 80x40 mm – transition: 20 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

Round-to-Rectangular Tube Adapter STL 3D file ⌀65 mm to 50×63 mm, thickness 2 mm 📦 #2228

1 object(s) - format STL

Latest user-generated 3D models

Tube adapter STL 3D file ⌀ 65–50 mm (Length: 40 mm) 📦 #11794

1 object(s) - format STL

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 #2630

1 object(s)

- format STL

Right-angle bracket 150×150 mm STL 3D file, thickness 12 mm, hole diameter 8 mm

Download this model of an angle bracket with a central reinforcing bar in STL 3D format. The dimensions are 150 mm in length, 150 mm in height, 30 mm in width, and 12 mm in thickness. The drill holes have a diameter of 8 mm. Chamfers are done to the holes to seat the screw heads. The reinforcing bar reduces bending and provides two clearances for screwdriver access. Support generation is not required for printing this bracket, printed flat on the build plate.

Parameter	Value	Unit
length	150	mm
height	150	mm
width	30	mm
thickness	12	mm
hole diameter	8	mm
chamfer on the holes	yes

📦 Model #6362

2 object(s)

- format STL

Rectangular-base box with lid STL 3D model – 84×45×20 mm, wall thickness 2 mm

Rectangular-base box with a lid provided as a STL 3D file. Overall dimensions are 84 mm long, 45 mm wide, and 20 mm tall. The box features thin 2 mm walls. Interior and exterior edges are rounded. A small clearance is included to ensure a precise fit between the box and the lid. The internal dimensions, excluding rounding, are 80 mm × 41 mm × 16 mm.

Parameter	Value	Unit
length	84	mm
width	45	mm
height	20	mm
wall thikness	2	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 #3109

1 object(s)

- format STL

Washer / Flat Gasket STL file ⌀ID: 19 mm ⌀OD: 29 mm thickness: 2 mm

File of gasket / washer in STL file format. This model features an inner diameter of ⌀19 mm and an outer diameter of ⌀29 mm. The thickness is 2 mm. No finish is available.

Parameter	Value	Unit
inner diameter	19	mm
outer diameter	29	mm
thickness	2	mm
finish	none

📦 Model #1057

1 object(s)

- format STL

O-ring STL file ID 50 × CS 2.5 mm

3D file in STL format of rubber ring with ID (inner diameter) 50 mm / thickness 2.5 mm. Outer diameter (OD) resulting corresponds to 55 mm.

Parameter	Value	Unit
inner diameter (ID)	50	mm
cross section (CS)	2.5	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

📦 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 #3703

1 object(s)

- format STL

Protective grid STL 3D file, center-to-center: 225x150mm, mesh: 3mm - Ø4mm

Download this rectangular honeycomb grid as a STL file. Mounting holes are placed at the four corners (center-to-center 225x150 mm), each with a diameter of Ø4 mm. The overall dimensions reach 233x158 mm, with fine 3 mm cell size for maximum protection. This grid serves as both a protective guard and a ventilation panel.

Parameter	Value	Unit
length or center-to-center	225	mm
width or center-to-center	150	mm
mesh size	3	mm
dual color	no
holes	yes
hole diameter	4	mm

📦 Model #1085

1 object(s)

- format STL

Multi-compartment box STL 3D file: 9 compartments of 16×26×10 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

📦 Model #1053

1 object(s)

- format STL

O-ring STL file ID 200 × CS 10 mm

3D model of O-ring with dimensions ID (inner diameter) 200 mm by thickness 10 mm. Outer diameter (OD) resulting is 220 mm.

Parameter	Value	Unit
inner diameter (ID)	200	mm
cross section (CS)	10	mm

📦 Model #1478

1 object(s)

- format STL

Tube adapter STL 3D file ⌀ 110–90 mm (Length: 215 mm)

Tube coupler ⌀110 mm to ⌀90 mm in STL 3D format. Length of this connector is 215 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 100 mm as well. The ends are rounded on the outside.

Parameter	Value	Unit
side A length	100	mm
side A outer diameter	110	mm
side A thickness	5	mm
side B length	100	mm
side B outer diameter	90	mm
side B thickness	5	mm
transition length	15	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 #2054

1 object(s)

- format STL

Round air vent STL 3D file ∅ 71 mm, slat angle: 40° with central reinforcement

Model of a round air vent for ventilation in STL format. Its insertion diameter measures 71 mm. The slats have an angle of 40° and a high thickness of 2.4 mm. A centered vertical reinforcement reinforces the slats. This 3D aeration grille has a thin flange of 4 mm. The full diameter of the model is 79 mm.

Parameter	Value	Unit
male diameter	71	mm
slat angle	40	°
slat thickness	2.4	mm
flange width	4	mm
central reinforcement	yes

📦 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 #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 #2295

1 object(s)

- format STL

Tube adapter STL file ⌀ 149–139 mm (Length: 80 mm)

Diameter adapter ⌀149 mm to ⌀139 mm in STL 3D format. Final length of this fitting is 80 mm. The thickness of the tubes is identical: 2 mm. The larger-diameter tube has a sleeve length of 30 mm, the smaller one of 30 mm as well. The ends have a fillet to make tube connection easier.

Parameter	Value	Unit
side A length	30	mm
side A outer diameter	149	mm
side A thickness	2	mm
side B length	30	mm
side B outer diameter	139	mm
side B thickness	2	mm
transition length	20	mm
axis offset	0	mm
ends fillet	fillet on bo...

📦 Model #2240

1 object(s)

- format STL

Pipe elbow STL file 45° ⌀OD: 35 mm ⌀ID: 11 mm thickness: 12 mm

3D model of a pipe elbow with a 45° angle in STL format. This elbow has an external diameter of 35 mm and an internal diameter of 11 mm. This results in a tube thickness of 12 mm.

Parameter	Value	Unit
outer diameter	35	mm
inner diameter	11	mm
angle	45	°
end fillets	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 #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 #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 #863

1 object(s)

- format STL

U-shaped handle STL 3D file 35×140×10 mm (Center-to-center 130 mm)

Download this STL 3D model of a simple U-shaped handle. The external dimensions are 35×140×10 mm. This handle features a round cross-section and a straight transition. The holes are 5 mm diameter and have a 130 mm center-to-center distance.

Parameter	Value	Unit
width	35	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	5	mm

📦 Model #2289

1 object(s)

- format STL

Tube adapter STL 3D file ⌀ 158–118 mm (Length: 65 mm)

Tube adapter ⌀158 mm to ⌀118 mm in STL format. Final length of this fitting is 65 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 are raw.

Parameter	Value	Unit
side A length	30	mm
side A outer diameter	158	mm
side A thickness	3	mm
side B length	30	mm
side B outer diameter	118	mm
side B thickness	3	mm
transition length	5	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 #2313

1 object(s)

- format STL

Tube adapter STL file ⌀ 77–57 mm (Length: 125 mm)

Inline tube junction ⌀77 mm to ⌀57 mm in STL format. Length of this fitting is 125 mm. The thickness of the tubes is identical: 2 mm. The larger-diameter tube has a sleeve length of 50 mm, the smaller one of 50 mm as well. The ends have no fillet.

Parameter	Value	Unit
side A length	50	mm
side A outer diameter	77	mm
side A thickness	2	mm
side B length	50	mm
side B outer diameter	57	mm
side B thickness	2	mm
transition length	25	mm
axis offset	0	mm
ends fillet	no fillet

📦 Model #3242

2 object(s)

- format STL

Enclosure with screw-mounted lid STL file: 50×50×40 mm

Download this enclosure model with screwed lid in 3D STL format. The dimensions are 50 mm long by 50 mm wide and 40 mm high. The cover only is 10 mm high. Side thickness is 3 mm. The enclosure does not have cooling.

Parameter	Value	Unit
length	50	mm
width	50	mm
total height	40	mm
lid height	10	mm
wall thickness	3	mm
screw margin	0.1	mm
fit clearance	0.1	mm
cooling zone(s)	no cutouts

📦 Model #2946

1 object(s)

- format STL

Washer / Flat Gasket STL 3D file ⌀ID: 57 mm ⌀OD: 80 mm thickness: 1.2 mm

Download this 3D file of washer / gasket in STL 3D file format. This part features an internal diameter of ⌀57 mm and an external diameter of ⌀80 mm. The part thickness is 1.2 mm. This part has no finish available.

Parameter	Value	Unit
inner diameter	57	mm
outer diameter	80	mm
thickness	1.2	mm
finish	none

📦 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 #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 #3147

1 object(s)

- format STL

Tubing adapter STL 3D file ⌀ 35–15 mm (Length: 55 mm)

Straight tube adapter ⌀35 mm to ⌀15 mm in STL 3D format. Length of this coupler is 55 mm. The thickness of the tubes is identical: 2 mm. The larger-diameter tube has a length of 5 mm, the smaller one of 30 mm. The ends are rounded on the inside.

Parameter	Value	Unit
side A length	5	mm
side A outer diameter	35	mm
side A thickness	2	mm
side B length	30	mm
side B outer diameter	15	mm
side B thickness	2	mm
transition length	20	mm
axis offset	0	mm
ends fillet	fillet on th...

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.