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

Tube adapter STL file ⌀ 50–40 mm (Length: 45 mm)

Enclosure with screw-mounted lid STL 3D file: 120×100×45 mm (with ventilation on the lid)

Pot STL file, inner: base Ø40 mm, top Ø80 mm, height 50 mm - wall thickness 3 mm

Rectangular tube adapter STL file 100x40 mm to 80x80 mm – transition: 80 mm

Enclosure with screw-mounted lid STL file: 100×100×20 mm (with ventilation on the lid and under the enclosure)

Rectangular duct adapter STL 3D file 100x20 mm to 80x20 mm – transition: 20 mm

Pipe elbow STL file 30° ⌀OD: 60 mm ⌀ID: 58 mm thickness: 1 mm

Small parts organizer with 4 drawers 100×10×50 mm STL 3D file, thickness: 2 mm

Small parts organizer with 25 drawers 40×30×50 mm STL 3D file, thickness: 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 prism STL 3D file 10×10×90 mm 📦 #1025

1 object(s) - format STL

View of object #0

Latest user-generated 3D models

Square box with lid STL 3D model – 65×65×37 mm, wall thickness 2 mm 📦 #9398

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 #1745

1 object(s)

- format STL

Tube adapter STL 3D file ⌀ 100–80 mm (Length: 100 mm)

Straight tube connector ⌀100 mm to ⌀80 mm in STL 3D format. Final length of this connector is 100 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 axes of the tubes are offset by 5 mm. The ends have a fillet to facilitate the connection of the two tubes.

Parameter	Value	Unit
side A length	30	mm
side A outer diameter	100	mm
side A thickness	2	mm
side B length	30	mm
side B outer diameter	80	mm
side B thickness	2	mm
transition length	40	mm
axis offset	5	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 #3168

1 object(s)

- format STL

Corner bracket 150×101 mm STL 3D file, thickness 5 mm, hole diameter 5 mm

Download this 3D file of a support bracket reinforced in STL 3D format. The dimensions are 150 mm in length, 101 mm in height, 15 mm in width, and 5 mm in thickness. The screw holes are designed with a diameter of 5 mm. Chamfers are done to the holes for a cleaner fit of the screws. The reinforcing bar improves rigidity and provides two passages for fastening. Support generation is not required for printing this bracket, placed flat directly on the build plate.

Parameter	Value	Unit
length	150	mm
height	101	mm
width	15	mm
thickness	5	mm
hole diameter	5	mm
chamfer on the holes	yes

📦 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 #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 #1963

2 object(s)

- format STL

Round box with lid STL 3D file ⌀ 29 mm - Height: 20 mm, Shell: 3 mm

Download this circular storage box in 3D STL format. Its diameter is 29 mm and its height is 20 mm. The wall width is 3 mm.

Parameter	Value	Unit
external diameter	29	mm
total height	20	mm
wall thickness	3	mm
fit clearance	0.1	mm
inner bottom fillet	0	mm

📦 Model #2524

1 object(s)

- format STL

Support bracket 210×100 mm STL 3D file, thickness 8 mm, hole diameter 6 mm

3D model of a mounting bracket with a central reinforcing bar in STL format. The dimensions are 210 mm in length, 100 mm in height, 50 mm in width, and 8 mm in thickness. The screw holes have a diameter of 6 mm. Chamfers are applied to the holes to seat the screw heads. The central reinforcement bar improves rigidity and provides two clearances for screwdriver access. This bracket prints without support, printed flat directly on the build plate.

Parameter	Value	Unit
length	210	mm
height	100	mm
width	50	mm
thickness	8	mm
hole diameter	6	mm
chamfer on the holes	yes

📦 Model #963

1 object(s)

- format STL

U-shaped handle STL 3D file 50×140×10 mm (Center-to-center 130 mm)

Download this STL file of a simple U-shaped drawer handle. The external dimensions are 50×140×10 mm. This handle features a square section and a 90-degree transition. A fillet ensures a more comfortable grip. The holes are 6 mm diameter and have a 130 mm center-to-center distance.

Parameter	Value	Unit
width	50	mm
length	140	mm
thickness	10	mm
shape (0:square,1:circle)	0
transition (0:right,1:rounded)	0
fillet radius	1	mm
hole diameter	6	mm

📦 Model #3362

1 object(s)

- format STL

Protective grid STL file, center-to-center: 65x65mm, mesh: 5mm - Ø4mm

Square protective honeycomb grid model as a STL file. Mounting holes are placed at the four corners (center-to-center 65x65 mm), each with a diameter of Ø4 mm. The overall dimensions reach 73x73 mm, with regular 5 mm cell size for balanced airflow and protection. This grid provides both mechanical protection and airflow.

Parameter	Value	Unit
length or center-to-center	65	mm
width or center-to-center	65	mm
mesh size	5	mm
dual color	no
holes	yes
hole diameter	4	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 #1610

1 object(s)

- format STL

Pipe elbow STL 3D file 90° ⌀OD: 22 mm ⌀ID: 20 mm thickness: 1 mm

Model of a pipe elbow with a 90° angle in STL format. This pipe elbow has an external diameter of 22 mm and an internal diameter of 20 mm. This results in a tube thickness of 1 mm. End fillets make it easier to insert.

Parameter	Value	Unit
outer diameter	22	mm
inner diameter	20	mm
angle	90	°
end fillets	yes

📦 Model #2863

2 object(s)

- format STL

Small parts organizer with 20 drawers 45×25×25 mm STL 3D file, thickness: 2 mm

File of a multi-drawer box in 3D STL format. This model contains 20 drawers, arranged in 5 rows and 4 columns. Specifically, this means 5 rows of 4 drawers. Each drawer offers a storage volume of 45 mm wide, 25 mm high, and 25 mm deep. The wall thickness is 2 mm. The overall dimensions of the structure measure 208 x 149.5 x 31 mm. All the objects in this model were designed to be printed without support.

Parameter	Value	Unit
number of rows	5
number of columns	4
inner drawer depth	25	mm
inner drawer width	45	mm
inner drawer height	25	mm
wall thickness	2	mm
removable divider	none

📦 Model #3309

1 object(s)

- format STL

Pipe clip Ø80 mm STL 3D file · Flat head screw Ø5 mm

3D model of a Ø80 mm pipe clip holder in STL format. The fastening is achieved by means of a countersunk screw Ø5 mm. This pipe clip is designed for a stable hold and simple mounting.

Parameter	Value	Unit
tube diameter	80	mm
hole diameter	5	mm
countersunk screw	yes

📦 Model #2149

1 object(s)

- format STL

Multi-compartment box STL file: 54 compartments of 40×40×25 mm

This STL file provides 54 compartments measuring 40×40×25mm each. The total dimensions of the box are 390×261×28mm. Fillets of 3mm applied to each compartment provide a better grip stored in the box. The separators are particularly reinforced.

Parameter	Value	Unit
number of rows	6
number of columns	9
compartment length	40	mm
compartment width	40	mm
compartment height	25	mm
wall thickness	3	mm
compartment fillet (radius)	3	mm

📦 Model #3447

1 object(s)

- format STL

Washer / Flat Gasket STL file ⌀ID: 9 mm ⌀OD: 18 mm thickness: 2.8 mm + chamfer

Download this 3D file of flat gasket / washer in STL 3D file format. This part features an inner diameter of ⌀9 mm and an outer diameter of ⌀18 mm. The total thickness is 2.8 mm. A chamfer is present on the inner diameter with a value of 1.2 mm.

Parameter	Value	Unit
inner diameter	9	mm
outer diameter	18	mm
thickness	2.8	mm
finish	chamfer
finish position	inner
sides	one side
finish value	1.2	mm

📦 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 #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 #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 #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 #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 #2844

1 object(s)

- format STL

Tube adapter STL 3D file ⌀ 12–6 mm (Length: 65 mm)

Straight tube reducer ⌀12 mm to ⌀6 mm in STL format. Total length of this connector is 65 mm. The thickness of the tubes is identical: 2 mm. The larger-diameter tube has a sleeve length of 20 mm, the smaller one of 20 mm as well. The ends have no fillet.

Parameter	Value	Unit
side A length	20	mm
side A outer diameter	12	mm
side A thickness	2	mm
side B length	20	mm
side B outer diameter	6	mm
side B thickness	2	mm
transition length	25	mm
axis offset	0	mm
ends fillet	no fillet

📦 Model #1679

1 object(s)

- format STL

Round-to-Rectangular Tube Adapter STL 3D file ⌀102 mm to 150×80 mm, thickness 5 mm + offset

Model in STL format of a round-to-rectangular adapter with an external diameter of ⌀102 mm and a rectangular section with inner dimensions 150×80 mm. The shell thickness is 5 mm and the total length is 170 mm. The adapter has an offset of 50 mm along the Z axis.

Parameter	Value	Unit
cylinder outer diameter	102	mm
cylinder inlet length	30	mm
rectangle internal length	150	mm
rectangle internal height	80	mm
rectangle inlet length	30	mm
offset Z	50	mm
offset Y	0	mm
total length	170	mm
thickness	5	mm
chamfer	no chamfer

📦 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 #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 #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 #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 #1543

1 object(s)

- format STL

O-ring STL file ID 120 × CS 5 mm

3D file of sealing ring with dimensions Internal diameter (ID) 120 mm by CS 5 mm. Outer diameter (OD) resulting is 130 mm.

Parameter	Value	Unit
inner diameter (ID)	120	mm
cross section (CS)	5	mm

📦 Model #2996

1 object(s)

- format STL

Tube adapter STL file ⌀ 60–35 mm (Length: 240 mm)

Straight tube fitting ⌀60 mm to ⌀35 mm in STL 3D format. Length of this adapter is 240 mm. The thickness of the tubes is identical: 3 mm. The larger-diameter tube has a sleeve length of 80 mm, the smaller one of 80 mm as well. The ends are raw.

Parameter	Value	Unit
side A length	80	mm
side A outer diameter	60	mm
side A thickness	3	mm
side B length	80	mm
side B outer diameter	35	mm
side B thickness	3	mm
transition length	80	mm
axis offset	0	mm
ends fillet	no fillet

📦 Model #3617

1 object(s)

- format STL

Angle bracket 160×100 mm STL 3D file, thickness 10 mm, hole diameter 8 mm

File of a right-angle bracket with a central reinforcing bar in STL format. The dimensions are 160 mm in length, 100 mm in height, 50 mm in width, and 10 mm in thickness. The screw holes are designed with a diameter of 8 mm. Chamfers are applied to the holes for a cleaner fit of the screws. The central reinforcement bar enhances mechanical strength and provides two clearances for fastening. Support generation is not required for printing this bracket, lying flat directly on the build plate.

Parameter	Value	Unit
length	160	mm
height	100	mm
width	50	mm
thickness	10	mm
hole diameter	8	mm
chamfer on the holes	yes

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.