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Featured Model of the Day

Tube adapter STL file ⌀ 210–20 mm (Length: 160 mm) 📦 #2156

1 object(s) - format STL

gizmo

Latest user-generated 3D models

Tubing elbow STL file 70° ⌀OD: 26.8 mm ⌀ID: 25 mm thickness: 0.9 mm 📦 #9308

1 object(s) - format STL

gizmo

From the Blog

Why Modeling Strategy Matters in Procedural CAD Modeling

2025-12-14 · 3D Modeling · sylvain
why Modeling Strategy Matters in Procedural CAD Modeling why Modeling Strategy Matters in Procedural CAD Modeling

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 #3502

1 object(s)
- format STL
Protective grid STL 3D file, 60x60mm, mesh: 8mm
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 #1197

4 object(s)
- format STL
Color-coded compartment box STL file: 9 compartments of 20×20×20 mm
Color-coded compartment box STL file: 9 compartments of 20×20×20 mm
View of object #0
This STL file for a sorting box with colored rings features 9 sections measuring 20×20×20 mm each. The total dimensions are 72×72×23 mm. The cavities are not equipped with any fillet.
Parameter Value Unit
number of rows 3
number of columns 3
compartment length 20 mm
compartment width 20 mm
compartment height 20 mm
wall thickness 3 mm
compartment fillet (radius) 0 mm
row colors ABC

📦 Model #2390

1 object(s)
- format STL
Round air vent STL 3D file ∅ 115 mm, slat angle: 45°
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 #2265

2 object(s)
- format STL
Enclosure with screw-mounted lid STL file: 86×86×179 mm
Enclosure with screw-mounted lid STL file: 86×86×179 mm
View of object #0
Enclosure model with lid in STL format. The dimensions are 86 mm long by 86 mm wide and 179 mm high. The cover measures 10 mm high. Wall thickness is 4 mm. The enclosure does not feature cooling.
Parameter Value Unit
length 86 mm
width 86 mm
total height 179 mm
lid height 10 mm
wall thickness 4 mm
screw margin 0 mm
fit clearance 0 mm
cooling zone(s) no cutouts

📦 Model #4396

1 object(s)
- format STL
Honeycomb grid STL file, 250x250mm, mesh: 10mm
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 #2019

1 object(s)
- format STL
Round-to-Rectangular Tube Adapter STL file ⌀95 mm to 120×148.5 mm, thickness 2 mm
Round-to-Rectangular Tube Adapter STL file ⌀95 mm to 120×148.5 mm, thickness 2 mm
Download this file in STL format of a round-to-rectangular tube adapter with an outer diameter of ⌀95 mm and a rectangular section with internal dimensions 120×148.5 mm. The shell thickness is 2 mm and the overall length is 100 mm.
Parameter Value Unit
cylinder outer diameter 95 mm
cylinder inlet length 50 mm
rectangle internal length 120 mm
rectangle internal height 148.5 mm
rectangle inlet length 5 mm
offset Z 0 mm
offset Y 0 mm
total length 100 mm
thickness 2 mm
chamfer no chamfer

📦 Model #3249

1 object(s)
- format STL
O'ring STL 3D file ID 28.5 × CS 3.6 mm
O'ring STL 3D file ID 28.5 × CS 3.6 mm
3D model of O-ring with Internal diameter 28.5 mm / CS (cross section) 3.6  mm. Outer diameter (OD, for outer diameter) is 35.7 mm.
Parameter Value Unit
inner diameter (ID) 28.5 mm
cross section (CS) 3.6 mm

📦 Model #3259

1 object(s)
- format STL
Tubing adapter STL file ⌀ 90–85 mm (Length: 39 mm)
Tubing adapter STL file ⌀ 90–85 mm (Length: 39 mm)
Tubing adapter ⌀90 mm to ⌀85 mm in STL 3D format. Final length of this junction is 39 mm. The thickness of the tubes is identical: 2 mm. The larger-diameter tube has a length of 18 mm, the smaller one of 16 mm. The ends are not rounded.
Parameter Value Unit
side A length 18 mm
side A outer diameter 90 mm
side A thickness 2 mm
side B length 16 mm
side B outer diameter 85 mm
side B thickness 2 mm
transition length 5 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
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
Round box with lid STL 3D file ⌀ 134 mm - Height: 20 mm, Shell: 2 mm
View of object #0
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 #4251

3 object(s)
- format STL
Small parts organizer with 25 drawers 65×35×138 mm STL 3D file, thickness: 3 mm
Small parts organizer with 25 drawers 65×35×138 mm STL 3D file, thickness: 3 mm
View of object #0
Download this 3D file of a multi-drawer unit in 3D STL format. This model features 25 drawers, arranged in 5 rows and 5 columns. Practically speaking, this means 5 rows of 5 drawers. Each drawer provides an inside space of 65 mm wide, 35 mm high, and 138 mm deep. The wall thickness is 3 mm, which makes the structure solid. The drawers come with 1 divider each, which allows up to 2 sections per drawer and up to 50 compartments in total. The external dimensions of the box are 375.5 x 210.5 x 147 mm. All the objects in this model are intended to be printed without support.
Parameter Value Unit
number of rows 5
number of columns 5
inner drawer depth 138 mm
inner drawer width 65 mm
inner drawer height 35 mm
wall thickness 3 mm
removable divider one divider ...

📦 Model #2126

1 object(s)
- format STL
Pipe elbow STL file 80° ⌀OD: 48.3 mm ⌀ID: 42.1 mm thickness: 3.1 mm
Pipe elbow STL file 80° ⌀OD: 48.3 mm ⌀ID: 42.1 mm thickness: 3.1 mm
Model of a pipe elbow with an 80° angle in STL format. This elbow has an external diameter of 48.3 mm and an internal diameter of 42.1 mm. This results in a tube thickness of 3.1 mm.
Parameter Value Unit
outer diameter 48.3 mm
inner diameter 42.1 mm
angle 80 °
end fillets no

📦 Model #4014

1 object(s)
- format STL
Round-to-Rectangular Tube Adapter STL file ⌀81 mm to 108×52 mm, thickness 3 mm + offset
Round-to-Rectangular Tube Adapter STL file ⌀81 mm to 108×52 mm, thickness 3 mm + offset
Download this 3D file in STL format of a round-to-rectangular adapter with an external diameter of ⌀81 mm and a rectangular section with internal dimensions 108×52 mm. The shell thickness is 3 mm and the total 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 108 mm
rectangle internal height 52 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)
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 #4201

1 object(s)
- format STL
Washer / Flat Gasket STL 3D file ⌀ID: 3.9 mm ⌀OD: 6.9 mm thickness: 4.3 mm
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 #3057

1 object(s)
- format STL
Right-angle bracket 150×150 mm STL 3D file, thickness 6 mm, hole diameter 6 mm
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 #3620

2 object(s)
- format STL
Round box with lid STL file ⌀ 27 mm - Height: 200 mm, Shell: 3 mm
Round box with lid STL file ⌀ 27 mm - Height: 200 mm, Shell: 3 mm
View of object #0
Download this round box in STL format. Its diameter is 27 mm and its height is 200 mm. The walls have a thickness of 3 mm.
Parameter Value Unit
external diameter 27 mm
total height 200 mm
wall thickness 3 mm
fit clearance 0.1 mm
inner bottom fillet 0 mm

📦 Model #4497

1 object(s)
- format STL
Tubing adapter STL 3D file ⌀ 32–19 mm (Length: 65 mm)
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 #982

1 object(s)
- format STL
U-shaped handle STL file 50×140×14 mm (Center-to-center 126 mm)
U-shaped handle STL file 50×140×14 mm (Center-to-center 126 mm)
Download this 3D model of a basic U-shaped handle. The overall dimensions are 50×140×14 mm. The handle features a square profile and a rounded transition. The bores are 4 mm diameter with a center-to-center distance of 126 mm.
Parameter Value Unit
width 50 mm
length 140 mm
thickness 14 mm
shape (0:square,1:circle) 0
transition (0:right,1:rounded) 1
fillet radius 0 mm
hole diameter 4 mm

📦 Model #4476

1 object(s)
- format STL
Tubing adapter STL 3D file ⌀ 40–37 mm (Length: 115 mm)
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 #2829

1 object(s)
- format STL
Tubing elbow STL file 90° ⌀OD: 24 mm ⌀ID: 22 mm thickness: 1 mm
Tubing elbow STL file 90° ⌀OD: 24 mm ⌀ID: 22 mm thickness: 1 mm
Model of a tubing elbow with a 90° angle in STL format. This elbow has an external diameter of 24 mm and an internal diameter of 22 mm. This results in a tube thickness of 1 mm.
Parameter Value Unit
outer diameter 24 mm
inner diameter 22 mm
angle 90 °
end fillets no

📦 Model #2684

2 object(s)
- format STL
Small parts organizer with 16 drawers 50×50×40 mm STL file, thickness: 3 mm
Small parts organizer with 16 drawers 50×50×40 mm STL file, thickness: 3 mm
View of object #0
Download this model of a multi-drawer box 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 offers a storage volume of 50 mm wide, 50 mm high, and 40 mm deep. The wall thickness is 3 mm, which makes the structure sturdy. The total size of the structure are 241 x 229 x 49 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 40 mm
inner drawer width 50 mm
inner drawer height 50 mm
wall thickness 3 mm
removable divider none

📦 Model #2334

1 object(s)
- format STL
Round-to-Rectangular Tube Adapter STL 3D file ⌀109 mm to 55×108 mm, thickness 2 mm + offset
Round-to-Rectangular Tube Adapter STL 3D file ⌀109 mm to 55×108 mm, thickness 2 mm + offset
Download this model in STL format of a round-to-rectangular adapter with an outer diameter of ⌀109 mm and a rectangular section with internal dimensions 55×108 mm. The wall thickness is 2 mm and the total length is 115 mm. The adapter has an offset of 20 mm along the Y axis and 37.5 mm along the Z axis. Chamfers are present on the outside of the cylindrical end and on the inside of the rectangular end to ease insertion.
Parameter Value Unit
cylinder outer diameter 109 mm
cylinder inlet length 20 mm
rectangle internal length 55 mm
rectangle internal height 108 mm
rectangle inlet length 20 mm
offset Z 37.5 mm
offset Y 20 mm
total length 115 mm
thickness 2 mm
chamfer chamfers on ...

📦 Model #4421

1 object(s)
- format STL
Protective grid STL file, 300x270mm, mesh: 10mm
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 #4045

1 object(s)
- format STL
Corner bracket 100×100 mm STL 3D file, thickness 5 mm, hole diameter 5 mm
Corner bracket 100×100 mm STL 3D file, thickness 5 mm, hole diameter 5 mm
Download this model of an angle bracket with a central reinforcing bar in STL format. The dimensions are 100 mm in length, 100 mm in height, 15 mm in width, and 5 mm in thickness. The holes have a diameter of 5 mm. Chamfers are done to the holes for a cleaner fit of the screws. The reinforcing bar improves rigidity and includes two openings for screwdriver access. Support generation is not required for printing this bracket, placed flat directly on the build plate.
Parameter Value Unit
length 100 mm
height 100 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)
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 #3612

1 object(s)
- format STL
Protective grid STL 3D file, center-to-center: 210x110mm, mesh: 10mm - Ø5mm
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 #2551

3 object(s)
- format STL
Small parts organizer with 12 drawers 42×47×130 mm STL 3D file, thickness: 2 mm
Small parts organizer with 12 drawers 42×47×130 mm STL 3D file, thickness: 2 mm
View of object #0
Download this 3D model of a sorting cabinet with drawers in STL format. This model contains 12 drawers, arranged in 3 rows and 4 columns. Specifically, this means 3 rows of 4 drawers. Each drawer provides an inside space of 42 mm wide, 47 mm high, and 130 mm deep. The wall thickness is 2 mm. The drawers come with 2 dividers each, which allows up to 3 compartments per drawer and up to 36 compartments in total. The overall dimensions of the structure come to 196 x 156.5 x 136 mm. All the objects in this model are intended to be printable without support generation.
Parameter Value Unit
number of rows 3
number of columns 4
inner drawer depth 130 mm
inner drawer width 42 mm
inner drawer height 47 mm
wall thickness 2 mm
removable divider two divider ...

📦 Model #1483

1 object(s)
- format STL
Tube adapter STL file ⌀ 200–50 mm (Length: 80 mm)
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 #4145

1 object(s)
- format STL
Honeycomb grille STL file, 195x80mm, mesh: 7mm
Honeycomb grille STL file, 195x80mm, mesh: 7mm
Download this rectangular protective grid file in STL format. The overall size is 195x80 mm, with wide 7 mm cell size to enhance ventilation. This grid acts as a protective guard while allowing airflow.
Parameter Value Unit
length or center-to-center 195 mm
width or center-to-center 80 mm
mesh size 7 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.