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

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Round air vent STL 3D file ∅ 152 mm, slat angle: 45° with central reinforcement

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

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

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

L-bracket 250×100 mm STL file, thickness 8 mm, hole diameter 6 mm

Round air vent STL 3D file ∅ 70 mm, slat angle: 45° with central reinforcement

Multi-compartment box STL 3D file: 6 compartments of 80×20×20 mm

Tube adapter STL file ⌀ 60–30 mm (Length: 140 mm)

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

Small parts organizer with 1 drawer 80×80×80 mm STL file, thickness: 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

Enclosure with screw-mounted lid STL file: 200×100×100 mm (with ventilation under the enclosure) 📦 #2751

2 object(s) - format STL

Latest user-generated 3D models

Washer / Flat Gasket STL file ⌀ID: 46 mm ⌀OD: 56 mm thickness: 3 mm 📦 #13433

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 #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 #2491

1 object(s)

- format STL

Tube adapter STL 3D file ⌀ 80–50 mm (Length: 250 mm)

Tube junction ⌀80 mm to ⌀50 mm in STL format. Total length of this reducer is 250 mm. The thickness of the tubes is identical: 3 mm. The larger-diameter tube has a length of 200 mm, the smaller one of 30 mm. The ends are raw.

Parameter	Value	Unit
side A length	200	mm
side A outer diameter	80	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 #1110

2 object(s)

- format STL

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

Get this round storage box model in STL format. Its diameter is 20 mm and its total height is 20 mm. The wall width is 2 mm. A fillet located at the bottom of the box makes it easier to grip stored objects inside.

Parameter	Value	Unit
external diameter	20	mm
total height	20	mm
wall thickness	2	mm
fit clearance	0.1	mm
inner bottom fillet	1	mm

📦 Model #2108

2 object(s)

- format STL

Small parts organizer with 9 drawers 60×45×150 mm STL 3D file, thickness: 4 mm

File of a storage box with drawers in 3D STL format. This model includes 9 compartments, arranged in 3 rows and 3 columns. In detail, this means 3 rows of 3 compartments. Each compartment offers a storage volume of 60 mm wide, 45 mm high, and 150 mm deep. The wall thickness is 4 mm, which makes the structure very sturdy. The overall dimensions of the structure measure 221.5 x 164.5 x 162 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	150	mm
inner drawer width	60	mm
inner drawer height	45	mm
wall thickness	4	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 #1037

1 object(s)

- format STL

O-ring STL file ID 4.47 × CS 1.78 mm

File of circular seal with dimensions ID (inner diameter) 4.47 mm × section thickness 1.78 mm. Final diameter is therefore 8.03 mm.

Parameter	Value	Unit
inner diameter (ID)	4.47	mm
cross section (CS)	1.78	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 #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 #778

1 object(s)

- format STL

Rectangular prism STL file 100×20×79 mm

Download a rectangular prism as a 3D STL file. Its overall dimensions are 100 by 20 by 79 mm. No fillet is applied to the sides.

Parameter	Value	Unit
length	100	mm
width	20	mm
height	79	mm
fillet radius	0	mm

📦 Model #3195

1 object(s)

- format STL

Bowl STL 3D file, inner: base Ø109 mm, top Ø109 mm, height 77 mm - wall thickness 2 mm

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

📦 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 #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 #2542

1 object(s)

- format STL

Tube adapter STL 3D file ⌀ 161–96 mm (Length: 150 mm)

Straight tube fitting ⌀161 mm to ⌀96 mm in STL format. Final length of this reducer is 150 mm. The thickness of the tubes is identical: 2 mm. The larger-diameter tube has a length of 25 mm, the smaller one of 25 mm as well. The ends have no fillet.

Parameter	Value	Unit
side A length	25	mm
side A outer diameter	161	mm
side A thickness	2	mm
side B length	25	mm
side B outer diameter	96	mm
side B thickness	2	mm
transition length	100	mm
axis offset	0	mm
ends fillet	no fillet

📦 Model #1099

1 object(s)

- format STL

Multi-compartment box STL 3D file: 24 compartments of 30×20×20 mm

This STL file includes 24 sections measuring 30×20×20mm each. The total dimensions are 194×90×22mm. Fillets of 2mm applied to each compartment provide a better grip stored in slots.

Parameter	Value	Unit
number of rows	4
number of columns	6
compartment length	30	mm
compartment width	20	mm
compartment height	20	mm
wall thickness	2	mm
compartment fillet (radius)	2	mm

📦 Model #2361

3 object(s)

- format STL

Small parts organizer with 16 drawers 40×40×70 mm STL 3D file, thickness: 2 mm

Download this model of a storage organizer in STL format. This model contains 16 drawers, arranged in 4 rows and 4 columns. In detail, this means 4 rows of 4 drawers. Each drawer measures 40 mm wide, 40 mm high, and 70 mm deep. The wall thickness is 2 mm. The drawers come with 1 divider each, which allows up to 2 compartments per drawer and up to 32 sections in total. The global dimensions of the box come to 188 x 180 x 76 mm. All the objects in this model are intended to be printed without support.

Parameter	Value	Unit
number of rows	4
number of columns	4
inner drawer depth	70	mm
inner drawer width	40	mm
inner drawer height	40	mm
wall thickness	2	mm
removable divider	one divider ...

📦 Model #4417

2 object(s)

- format STL

Enclosure with screw-mounted lid STL 3D file: 120×100×35 mm (with ventilation on the lid and under the enclosure)

Download this enclosure with lid in 3D STL format. The dimensions are 120 mm long by 100 mm wide and 35 mm high. The lid is 10 mm high. Wall thickness is 2 mm. This enclosure has significant cooling area on the lid and under the base.

Parameter	Value	Unit
length	120	mm
width	100	mm
total height	35	mm
lid height	10	mm
wall thickness	2	mm
screw margin	0	mm
fit clearance	0.1	mm
cooling level	8
cooling zone(s)	cutouts on b...

📦 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 #4022

1 object(s)

- format STL

Round-to-Rectangular Tube Adapter STL 3D file ⌀81 mm to 110×54 mm, thickness 3 mm + offset

File in STL format of a round-to-rectangular tube adapter with an outer diameter of ⌀81 mm and a rectangular section with inner dimensions 110×54 mm. The shell thickness is 3 mm and the overall length is 70 mm. The adapter has an offset of 10 mm along the Y axis and 20 mm along the Z axis.

Parameter	Value	Unit
cylinder outer diameter	81	mm
cylinder inlet length	15	mm
rectangle internal length	110	mm
rectangle internal height	54	mm
rectangle inlet length	15	mm
offset Z	20	mm
offset Y	10	mm
total length	70	mm
thickness	3	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...

📦 Model #1479

1 object(s)

- format STL

Tube adapter STL file ⌀ 110–100 mm (Length: 225 mm)

Inline tube coupler ⌀110 mm to ⌀100 mm in STL 3D format. Final length of this fitting is 225 mm. The thickness of the tubes is identical: 5 mm. The larger-diameter tube has a sleeve length of 110 mm, the smaller one of 100 mm. The ends have a fillet on the outside.

Parameter	Value	Unit
side A length	110	mm
side A outer diameter	110	mm
side A thickness	5	mm
side B length	100	mm
side B outer diameter	100	mm
side B thickness	5	mm
transition length	15	mm
axis offset	0	mm
ends fillet	fillet on th...

📦 Model #4301

1 object(s)

- format STL

Protective grid STL file, 300x50mm, mesh: 10mm

Download this rectangular protective grid as a STL file. The overall size is 300x50 mm, with very open 10 mm cell size for peak ventilation. This grid acts as a protective guard while allowing airflow.

Parameter	Value	Unit
length or center-to-center	300	mm
width or center-to-center	50	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 #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 #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 #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 #2051

1 object(s)

- format STL

Pipe elbow STL file 90° ⌀OD: 45.7 mm ⌀ID: 40.7 mm thickness: 2.5 mm

3D model of a pipe elbow with a 90° angle in STL format. This pipe elbow features an outer diameter of 45.7 mm and an inner diameter of 40.7 mm. The tube thickness is therefore 2.5 mm.

Parameter	Value	Unit
outer diameter	45.7	mm
inner diameter	40.7	mm
angle	90	°
end fillets	no

📦 Model #2315

1 object(s)

- format STL

Shelf bracket 150×100 mm STL 3D file, thickness 12 mm, hole diameter 6 mm

Model of a right-angle bracket with a central reinforcing bar in STL format. The dimensions are 150 mm in length, 100 mm in height, 14 mm in width, and 12 mm in thickness. The holes are designed with a diameter of 6 mm. Chamfers are done to the holes to improve the seating of the heads. The central reinforcement bar reduces bending and includes two openings for fastening. No support is needed to print this bracket, lying flat on the build plate.

Parameter	Value	Unit
length	150	mm
height	100	mm
width	14	mm
thickness	12	mm
hole diameter	6	mm
chamfer on the holes	yes

📦 Model #3370

1 object(s)

- format STL

Box STL 3D file with dimensions 50×50×100 mm

This one-slot box design includes a single compartment measuring 50×50×100mm. Overall dimensions of the box are 70×70×110mm. A 12mm fillet helps with item retrieval inside the compartment. The separators are particularly thick.

Parameter	Value	Unit
number of rows	1
number of columns	1
compartment length	50	mm
compartment width	50	mm
compartment height	100	mm
wall thickness	10	mm
compartment fillet (radius)	12	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

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.