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

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

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

Round-to-Rectangular Tube Adapter STL 3D file ⌀20 mm to 20×20 mm, thickness 2 mm + offset

Round air vent STL file ∅ 300 mm, slat angle: 30° with central reinforcement

Hose-shaped reducer STL 3D file 90.1x90 mm to 100x40 mm – transition: 100 mm

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

Pipe elbow STL 3D file 90° ⌀OD: 40 mm ⌀ID: 34 mm thickness: 3 mm

Enclosure with screw-mounted lid STL file: 80×80×40 mm (with ventilation on the lid)

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

Round box with lid STL 3D file ⌀ 45 mm - Height: 100 mm, Shell: 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

Rectangular-base box with lid STL 3D model – 170×95×110 mm, wall thickness 3 mm 📦 #6422

2 object(s) - format STL

Latest user-generated 3D models

Pipe clip holder Ø54 mm STL 3D file · Flat head screw Ø5 mm 📦 #12046

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 #4356

1 object(s)

- format STL

Multi-compartment box STL file: 12 compartments of 75×50×25 mm

This 3D model in STL format provides 12 compartments measuring 75×50×25mm each. The total dimensions of the box are 471×109×28mm. Fillets of 10mm applied to each compartment provide a better grip stored in slots. The dividers are particularly reinforced.

Parameter	Value	Unit
number of rows	2
number of columns	6
compartment length	75	mm
compartment width	50	mm
compartment height	25	mm
wall thickness	3	mm
compartment fillet (radius)	10	mm

📦 Model #1267

1 object(s)

- format STL

Round air vent STL 3D file ∅ 50 mm, slat angle: 60° with central reinforcement

File of a round air vent for air circulation in STL format. Its male diameter is 50 mm. The slats have a steep angle of 60° and a high thickness of 2.4 mm. A centered vertical reinforcement strengthens the whole structure. This aeration grille has a thin flange of 5 mm. The total diameter of this model is 60 mm.

Parameter	Value	Unit
male diameter	50	mm
slat angle	60	°
slat thickness	2.4	mm
flange width	5	mm
central reinforcement	yes

📦 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 #4439

1 object(s)

- format STL

Rectangular duct adapter STL 3D file 96x51.2 mm to 40x26.2 mm – transition: 55 mm

Rectangular duct transition downloadable as STL 3D file. The internal cross-section on side A is 96x51.2 mm (rectangular), while side B is 40x26.2 mm (rectangular). Both side A and side B sleeves share the same insertion length of 30 mm. Between the two sleeves, the transition section adds 55 mm, giving an overall length of 115 mm. Inner and outer edges at both ends are left unchamfered. Relative to side A, side B is shifted by 25 mm along the Z axis.

Parameter	Value	Unit
side A internal width	96	mm
side A internal height	51.2	mm
sleeve length on side A	30	mm
side B internal width	40	mm
side B internal height	26.2	mm
sleeve length on side B	30	mm
thickness	2	mm
transition length	55	mm
Y offset	0	mm
Z offset	25	mm
end chamfers	none

📦 Model #1041

1 object(s)

- format STL

O-ring STL 3D file ID 3 × CS 1.5 mm

Model of rubber ring with Internal diameter (ID) 3 mm / section thickness 1.5 mm. The outer diameter resulting corresponds to 6 mm.

Parameter	Value	Unit
inner diameter (ID)	3	mm
cross section (CS)	1.5	mm

📦 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 #2683

1 object(s)

- format STL

Support bracket 250×225 mm STL file, thickness 8 mm, hole diameter 5 mm

Download this file of a corner bracket with a reinforcing bar in STL 3D format. The dimensions are 250 mm in length, 225 mm in height, 30 mm in width, and 8 mm in thickness. The drill holes are designed with a diameter of 5 mm. Chamfers are applied to the holes for a cleaner fit of the screws. The reinforcing bar improves rigidity and provides two openings for screwdriver access. No support is needed to print this bracket, printed flat on the build plate.

Parameter	Value	Unit
length	250	mm
height	225	mm
width	30	mm
thickness	8	mm
hole diameter	5	mm
chamfer on the holes	yes

📦 Model #2811

2 object(s)

- format STL

Small parts organizer with 1 drawer 50×50×50 mm STL 3D file, thickness: 3 mm

3D file of a DIY organizer in 3D STL format. This model contains 1 compartment, arranged in 1 rows and 1 columns. In detail, this means 1 rows of 1 compartments. Each compartment measures 50 mm wide, 50 mm high, and 50 mm deep. The wall thickness is 3 mm, which makes the structure solid. The global dimensions of the structure are 62.5 x 59.5 x 59 mm. All the objects in this model were designed to be printed without support generation.

Parameter	Value	Unit
number of rows	1
number of columns	1
inner drawer depth	50	mm
inner drawer width	50	mm
inner drawer height	50	mm
wall thickness	3	mm
removable divider	none

📦 Model #2337

2 object(s)

- format STL

Small parts organizer with 6 drawers 25×14×73 mm STL file, thickness: 2 mm

3D file of a storage case in 3D STL format. This model features 6 boxes, arranged in 2 rows and 3 columns. Specifically, this means 2 rows of 3 boxes. Each box offers a storage volume of 25 mm wide, 14 mm high, and 73 mm deep. The wall thickness is 2 mm. The external dimensions of the structure are 96.5 x 39 x 79 mm. All the objects in this model are intended to be printable without support.

Parameter	Value	Unit
number of rows	2
number of columns	3
inner drawer depth	73	mm
inner drawer width	25	mm
inner drawer height	14	mm
wall thickness	2	mm
removable divider	none

📦 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 #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 #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 #3495

1 object(s)

- format STL

Honeycomb grid STL 3D file, center-to-center: 120x120mm, mesh: 5mm - Ø6mm

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 Ø6 mm. The overall dimensions reach 132x132 mm, with standard 5 mm cell size for versatile use. This grid acts as a protective guard while allowing airflow.

Parameter	Value	Unit
length or center-to-center	120	mm
width or center-to-center	120	mm
mesh size	5	mm
dual color	no
holes	yes
hole diameter	6	mm

📦 Model #1381

1 object(s)

- format STL

Pipe elbow STL file 60° ⌀OD: 32 mm ⌀ID: 28 mm thickness: 2 mm

Model of a pipe elbow with a 60° angle in STL format. This pipe elbow has an outer diameter of 32 mm and an inner diameter of 28 mm. The tube thickness is therefore 2 mm. The ends feature fillets to make it easier to assemble.

Parameter	Value	Unit
outer diameter	32	mm
inner diameter	28	mm
angle	60	°
end fillets	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 #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 #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 #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 #2827

1 object(s)

- format STL

Tubing adapter STL 3D file ⌀ 58–47 mm (Length: 85 mm)

Tube coupler ⌀58 mm to ⌀47 mm in STL format. Length of this fitting is 85 mm. The larger-diameter tube has a thickness of 2.5 mm and a length of 35 mm. The smaller-diameter tube has a thickness of 3.2 mm and a length of 35 mm as well. The ends are rounded on the outside to ease the connection.

Parameter	Value	Unit
side A length	35	mm
side A outer diameter	58	mm
side A thickness	2.5	mm
side B length	35	mm
side B outer diameter	47	mm
side B thickness	3.2	mm
transition length	15	mm
axis offset	0	mm
ends fillet	fillet on th...

📦 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 #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 #816

1 object(s)

- format STL

U-shaped handle STL file 35×100×14 mm (Center-to-center 86 mm)

Download this STL 3D model of a simple U-shaped handle. The overall dimensions are 35×100×14 mm. The handle has a square section and a right-angled transition. The holes are 6 mm diameter with a center-to-center distance of 86 mm.

Parameter	Value	Unit
width	35	mm
length	100	mm
thickness	14	mm
shape (0:square,1:circle)	0
transition (0:right,1:rounded)	0
fillet radius	0	mm
hole diameter	6	mm

📦 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 #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 #3164

1 object(s)

- format STL

Pot STL 3D file, inner: base Ø121 mm, top Ø122 mm, height 40 mm - wall thickness 1 mm

3D file of a container in STL 3D format. This model can be used for organizing small parts in a workshop or on a desk. The shape is almost straight, with a inner height of 40 mm, a inner diameter at the top of 122 mm, and a inner diameter at the bottom of 121 mm. The total height is 41 mm.

Parameter	Value	Unit
inner bottom diameter	121	mm
inner top diameter	122	mm
inner height	40	mm
wall thickness	1	mm

📦 Model #4421

1 object(s)

- format STL

Protective grid STL file, 300x270mm, mesh: 10mm

3D rectangular protective honeycomb grid model as a STL file. The overall size is 300x270 mm, with extra wide 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	300	mm
width or center-to-center	270	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 #2962

1 object(s)

- format STL

Shelf bracket 100×100 mm STL 3D file, thickness 5 mm, hole diameter 7 mm

File of an angle bracket with a central reinforcing bar in STL 3D format. The dimensions are 100 mm in length, 100 mm in height, 30 mm in width, and 5 mm in thickness. The drill holes are designed with a diameter of 7 mm. Chamfers are applied to the holes to seat the screw heads. The central reinforcement bar enhances mechanical strength and includes two passages for screwdriver access. No support is needed to print this bracket, placed flat directly on the build plate.

Parameter	Value	Unit
length	100	mm
height	100	mm
width	30	mm
thickness	5	mm
hole diameter	7	mm
chamfer on the holes	yes

📦 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 #909

1 object(s)

- format STL

U-shaped handle STL 3D file 50×100×10 mm (Center-to-center 90 mm)

Download this STL 3D model of a simple U-shaped handle. The external dimensions are 50×100×10 mm. The handle has a square cross-section and a 90-degree transition. A fillet produces a softer grip. The mounting holes are 6 mm diameter with a center-to-center distance of 90 mm.

Parameter	Value	Unit
width	50	mm
length	100	mm
thickness	10	mm
shape (0:square,1:circle)	0
transition (0:right,1:rounded)	0
fillet radius	1	mm
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.