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

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Tube adapter STL file ⌀ 100–60 mm (Length: 70 mm)

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

Round air vent STL file ∅ 90 mm, slat angle: 35°

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

Rectangular duct adapter STL 3D file 200x90 mm to 80x80 mm – transition: 60 mm

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

Tube support clip Ø200 mm STL file · Round head screw Ø8 mm

Round box with lid STL file ⌀ 45 mm - Height: 40 mm, Shell: 2 mm

Rectangular pipe adapter STL 3D file 60x60 mm to 80x80 mm – transition: 180 mm

Honeycomb grid STL file, center-to-center: 32x32mm, mesh: 4mm - Ø4mm

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 3D model – 240×160×200 mm, wall thickness 4 mm 📦 #10079

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 #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 #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 #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 #2359

1 object(s)

- format STL

Tube adapter STL file ⌀ 66–40 mm (Length: 75 mm)

Diameter adapter ⌀66 mm to ⌀40 mm in STL format. Total length of this coupler is 75 mm. The thickness of the tubes is identical: 2 mm. The larger-diameter tube has a length of 40 mm, the smaller one of 30 mm. The ends are not rounded.

Parameter	Value	Unit
side A length	40	mm
side A outer diameter	66	mm
side A thickness	2	mm
side B length	30	mm
side B outer diameter	40	mm
side B thickness	2	mm
transition length	5	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 #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 #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 #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 #2174

1 object(s)

- format STL

Pipe elbow STL 3D file 45° ⌀OD: 70 mm ⌀ID: 60 mm thickness: 5 mm

File of an elbow with a 45° angle in STL format. This pipe elbow features an external diameter of 70 mm and an internal diameter of 60 mm. The tube thickness is therefore 5 mm. The ends feature fillets to make it easier to insert.

Parameter	Value	Unit
outer diameter	70	mm
inner diameter	60	mm
angle	45	°
end fillets	yes

📦 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 #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 #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 #1055

1 object(s)

- format STL

O'ring STL file ID 40 × CS 4 mm

STL file of O-ring with dimensions ID (inner diameter) 40 mm / section thickness 4 mm. The outer diameter resulting is 48 mm.

Parameter	Value	Unit
inner diameter (ID)	40	mm
cross section (CS)	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 #3235

1 object(s)

- format STL

Tube adapter STL 3D file ⌀ 90–50 mm (Length: 130 mm)

Inline tube coupler ⌀90 mm to ⌀50 mm in STL 3D format. Total length of this connector is 130 mm. The thickness of the tubes is identical: 2.5 mm. The larger-diameter tube has a length of 50 mm, the smaller one of 40 mm. The two axes of the tubes are offset by 1 mm. The ends feature an external fillet to make tube connection easier.

Parameter	Value	Unit
side A length	50	mm
side A outer diameter	90	mm
side A thickness	2.5	mm
side B length	40	mm
side B outer diameter	50	mm
side B thickness	2.5	mm
transition length	40	mm
axis offset	1	mm
ends fillet	fillet on th...

📦 Model #1481

1 object(s)

- format STL

Round air vent STL file ∅ 152 mm, slat angle: 30° with central reinforcement

File of a round vent cover for air circulation in STL format. Its insertion diameter measures 152 mm. The slats have a slight angle of 30° and a high thickness of 2 mm. A centered vertical reinforcement strengthens the whole structure. This 3D aeration grille features a collar of 10 mm. The overall diameter of the model is 172 mm.

Parameter	Value	Unit
male diameter	152	mm
slat angle	30	°
slat thickness	2	mm
flange width	10	mm
central reinforcement	yes

📦 Model #1925

1 object(s)

- format STL

Tube adapter STL file ⌀ 15–9 mm (Length: 40 mm)

Tube adapter ⌀15 mm to ⌀9 mm in STL 3D format. Total length of this adapter is 40 mm. The thickness of the tubes is identical: 2 mm. The larger-diameter tube has a sleeve length of 10 mm, the smaller one of 10 mm as well. The two axes of the tubes are offset by 2.9 mm. The ends are not rounded.

Parameter	Value	Unit
side A length	10	mm
side A outer diameter	15	mm
side A thickness	2	mm
side B length	10	mm
side B outer diameter	9	mm
side B thickness	2	mm
transition length	20	mm
axis offset	2.9	mm
ends fillet	no fillet

📦 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 #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 #2081

1 object(s)

- format STL

Round-to-Rectangular Tube Adapter STL 3D file ⌀206 mm to 300×50 mm, thickness 3 mm

3D model in STL format of a round-to-rectangular adapter with an external diameter of ⌀206 mm and a rectangular section with internal dimensions 300×50 mm. The shell thickness is 3 mm and the overall length is 150 mm. Chamfers are present on the outside of the cylindrical end and on the inside of the rectangular end.

Parameter	Value	Unit
cylinder outer diameter	206	mm
cylinder inlet length	10	mm
rectangle internal length	300	mm
rectangle internal height	50	mm
rectangle inlet length	47	mm
offset Z	0	mm
offset Y	0	mm
total length	150	mm
thickness	3	mm
chamfer	chamfers on ...

📦 Model #4236

1 object(s)

- format STL

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

STL 3D file for an oval duct transition adapter. The internal cross-sections on sides A and B are identical, 60x20 mm. The useful length is consistent on both ends: 15 mm. Between the two sleeves, the transition runs over 140 mm, resulting in an overall length of 170 mm. Both the inner and outer edges at the ends remain unchamfered. An offset of 40 mm along the Y axis and 70 mm along the Z axis is applied to side B relative to side A.

Parameter	Value	Unit
side A internal width	60	mm
side A internal height	20	mm
sleeve length on side A	15	mm
side B internal width	60	mm
side B internal height	20	mm
sleeve length on side B	15	mm
thickness	3	mm
transition length	140	mm
Y offset	40	mm
Z offset	70	mm
end chamfers	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...

📦 Model #1897

1 object(s)

- format STL

Round-to-Rectangular Tube Adapter STL file ⌀90 mm to 200×60 mm, thickness 3 mm + offset

Download this 3D file in STL format of a round-to-rectangular adapter with an outer diameter of ⌀90 mm and a rectangular section with internal dimensions 200×60 mm. The wall thickness is 3 mm and the overall length is 200 mm. The adapter has an offset of 60 mm along the Z axis. A chamfer is applied on the outside of the cylindrical end.

Parameter	Value	Unit
cylinder outer diameter	90	mm
cylinder inlet length	30	mm
rectangle internal length	200	mm
rectangle internal height	60	mm
rectangle inlet length	30	mm
offset Z	60	mm
offset Y	0	mm
total length	200	mm
thickness	3	mm
chamfer	chamfer on t...

📦 Model #2467

1 object(s)

- format STL

Pipe elbow STL 3D file 45° ⌀OD: 60 mm ⌀ID: 56 mm thickness: 2 mm

3D file of a pipe elbow with a 45° angle in STL format. This pipe elbow has an external diameter of 60 mm and an internal diameter of 56 mm. The tube thickness is therefore 2 mm. End fillets make it easier to insert.

Parameter	Value	Unit
outer diameter	60	mm
inner diameter	56	mm
angle	45	°
end fillets	yes

📦 Model #4512

1 object(s)

- format STL

Tube elbow STL file 45° ⌀OD: 40 mm ⌀ID: 25 mm thickness: 7.5 mm

3D model of an elbow with a 45° angle in STL format. This pipe elbow has an external diameter of 40 mm and an internal diameter of 25 mm. The tube thickness is therefore 7.5 mm.

Parameter	Value	Unit
outer diameter	40	mm
inner diameter	25	mm
angle	45	°
end fillets	no

📦 Model #2119

1 object(s)

- format STL

Tube adapter STL file ⌀ 30–17 mm (Length: 90 mm)

Inline tube coupler ⌀30 mm to ⌀17 mm in STL format. Length of this junction is 90 mm. The thickness of the tubes is identical: 2 mm. The larger-diameter tube has a length of 30 mm, the smaller one of 30 mm as well. The ends are rounded to make tube connection easier.

Parameter	Value	Unit
side A length	30	mm
side A outer diameter	30	mm
side A thickness	2	mm
side B length	30	mm
side B outer diameter	17	mm
side B thickness	2	mm
transition length	30	mm
axis offset	0	mm
ends fillet	fillet on bo...

📦 Model #3921

1 object(s)

- format STL

Round air vent STL 3D file ∅ 93 mm, slat angle: 45° with central reinforcement

File of a round grille for air circulation in STL format. Its insertion diameter is 93 mm. The slats have an angle of 45° and a high thickness of 2 mm. A centered vertical reinforcement strengthens the whole structure. This 3D vent cover has a thin flange of 4 mm. The full diameter of this model is 101 mm.

Parameter	Value	Unit
male diameter	93	mm
slat angle	45	°
slat thickness	2	mm
flange width	4	mm
central reinforcement	yes

📦 Model #2686

2 object(s)

- format STL

Small parts organizer with 9 drawers 40×30×50 mm STL 3D file, thickness: 2 mm

3D file of storage drawers in STL format. This model includes 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 40 mm wide, 30 mm high, and 50 mm deep. The wall thickness is 2 mm. The global dimensions of the structure come to 141.5 x 105.5 x 56 mm. All the objects in this model are intended to be printed without support generation.

Parameter	Value	Unit
number of rows	3
number of columns	3
inner drawer depth	50	mm
inner drawer width	40	mm
inner drawer height	30	mm
wall thickness	2	mm
removable divider	none

📦 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

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.