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Featured Model of the Day

Round-to-Rectangular Tube Adapter STL 3D file ⌀65 mm to 50×63 mm, thickness 2 mm 📦 #2228

1 object(s) - format STL

gizmo

View of object #0

Latest user-generated 3D models

Square box with lid STL 3D model – 116×116×28 mm, wall thickness 5 mm 📦 #11871

2 object(s) - format STL

gizmo

View of object #0

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 #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 #2581

1 object(s)
- format STL
Round air vent STL 3D file ∅ 115 mm, slat angle: 10° with central reinforcement
Round air vent STL 3D file ∅ 115 mm, slat angle: 10° with central reinforcement
Design of a round grille for ventilation in STL format. Its insertion diameter measures 115 mm. The slats have a slight angle of 10° and a high thickness of 2 mm. A centered vertical reinforcement secures the whole structure. This aeration grille has a prominent flange of 17 mm. The total diameter of the model is 149 mm.
Parameter Value Unit
male diameter 115 mm
slat angle 10 °
slat thickness 2 mm
flange width 17 mm
central reinforcement 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 #2852

1 object(s)
- format STL
Tubing adapter STL file ⌀ 17–16 mm (Length: 25 mm)
Tubing adapter STL file ⌀ 17–16 mm (Length: 25 mm)
Inline tube reducer ⌀17 mm to ⌀16 mm in STL 3D format. Length of this sleeve is 25 mm. The thickness of the tubes is identical: 2 mm. The larger-diameter tube has a length of 10 mm, the smaller one of 10 mm as well. The ends have no fillet.
Parameter Value Unit
side A length 10 mm
side A outer diameter 17 mm
side A thickness 2 mm
side B length 10 mm
side B outer diameter 16 mm
side B thickness 2 mm
transition length 5 mm
axis offset 0 mm
ends fillet no fillet

📦 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 #4175

1 object(s)
- format STL
Tube adapter STL 3D file ⌀ 15–12 mm (Length: 25 mm)
Tube adapter STL 3D file ⌀ 15–12 mm (Length: 25 mm)
Inline tube reducer ⌀15 mm to ⌀12 mm in STL 3D format. Length of this coupler is 25 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 ends are raw.
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 12 mm
side B thickness 2 mm
transition length 5 mm
axis offset 0 mm
ends fillet no fillet

📦 Model #937

1 object(s)
- format STL
U-shaped handle STL 3D file 50×100×14 mm (Center-to-center 86 mm)
U-shaped handle STL 3D file 50×100×14 mm (Center-to-center 86 mm)
Download this STL file of a simple U-shaped furniture handle. The overall dimensions are 50×100×14 mm. The handle features a round cross-section combined with a smooth transition. The bores are 4 mm diameter and have a 86 mm center-to-center distance.
Parameter Value Unit
width 50 mm
length 100 mm
thickness 14 mm
shape (0:square,1:circle) 1
transition (0:right,1:rounded) 1
fillet radius 0 mm
hole diameter 4 mm

📦 Model #3937

2 object(s)
- format STL
Enclosure with screw-mounted lid STL file: 100×70×50 mm
Enclosure with screw-mounted lid STL file: 100×70×50 mm
View of object #0
Download this enclosure model with a screwed lid in 3D STL format. The dimensions are 100 mm long by 70 mm wide and 50 mm high. The cover only measures 12 mm high. Wall thickness is 2 mm. The enclosure does not feature cooling.
Parameter Value Unit
length 100 mm
width 70 mm
total height 50 mm
lid height 12 mm
wall thickness 2 mm
screw margin 0 mm
fit clearance 0.1 mm
cooling zone(s) no cutouts

📦 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 #1801

1 object(s)
- format STL
Tube adapter STL file ⌀ 110–100 mm (Length: 35 mm)
Tube adapter STL file ⌀ 110–100 mm (Length: 35 mm)
Tube coupler ⌀110 mm to ⌀100 mm in STL format. Final length of this adapter is 35 mm. The thickness of the tubes is identical: 3 mm. The larger-diameter tube has a sleeve length of 20 mm, the smaller one of 10 mm. The ends are raw.
Parameter Value Unit
side A length 20 mm
side A outer diameter 110 mm
side A thickness 3 mm
side B length 10 mm
side B outer diameter 100 mm
side B thickness 3 mm
transition length 5 mm
axis offset 0 mm
ends fillet no fillet

📦 Model #1600

1 object(s)
- format STL
Tube adapter STL 3D file ⌀ 100–53 mm (Length: 100 mm)
Tube adapter STL 3D file ⌀ 100–53 mm (Length: 100 mm)
Inline fitting ⌀100 mm to ⌀53 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 sleeve length of 30 mm, the smaller one of 30 mm as well. The ends feature an internal 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 53 mm
side B thickness 2 mm
transition length 40 mm
axis offset 0 mm
ends fillet fillet on th...

📦 Model #1260

1 object(s)
- format STL
Tube adapter STL 3D file ⌀ 45–10 mm (Length: 90 mm)
Tube adapter STL 3D file ⌀ 45–10 mm (Length: 90 mm)
Inline sleeve ⌀45 mm to ⌀10 mm in STL format. Total length of this connector is 90 mm. The larger-diameter tube has a thickness of 2.5 mm and a length of 30 mm. The smaller-diameter tube has a thickness of 2 mm and a length of 30 mm as well. The ends have no fillet.
Parameter Value Unit
side A length 30 mm
side A outer diameter 45 mm
side A thickness 2.5 mm
side B length 30 mm
side B outer diameter 10 mm
side B thickness 2 mm
transition length 30 mm
axis offset 0 mm
ends fillet no fillet

📦 Model #2211

3 object(s)
- format STL
Small parts organizer with 18 drawers 30×30×90 mm STL 3D file, thickness: 4 mm
Small parts organizer with 18 drawers 30×30×90 mm STL 3D file, thickness: 4 mm
View of object #0
Download this model of a drawer organizer in 3D STL format. This model features 18 boxes, arranged in 6 rows and 3 columns. Specifically, this means 6 rows of 3 boxes. Each box offers a storage volume of 30 mm wide, 30 mm high, and 90 mm deep. The wall thickness is 4 mm, which makes the structure very solid. The boxes feature 2 dividers each, which allows up to 3 compartments per box and up to 54 sections in total. The total size of the structure come to 131.5 x 235 x 102 mm. All the objects in this model were designed to be printable without support generation.
Parameter Value Unit
number of rows 6
number of columns 3
inner drawer depth 90 mm
inner drawer width 30 mm
inner drawer height 30 mm
wall thickness 4 mm
removable divider two divider ...

📦 Model #4415

2 object(s)
- format STL
Round box with lid STL file ⌀ 115 mm - Height: 42 mm, Shell: 3 mm
Round box with lid STL file ⌀ 115 mm - Height: 42 mm, Shell: 3 mm
View of object #0
Get this circular organizing box in 3D STL format. Its diameter is 115 mm and its total height is 42 mm. The wall width is 3 mm. A fillet located at the bottom of the box makes it easier to grab objects.
Parameter Value Unit
external diameter 115 mm
total height 42 mm
wall thickness 3 mm
fit clearance 0.2 mm
inner bottom fillet 1 mm

📦 Model #2404

1 object(s)
- format STL
Tube adapter STL 3D file ⌀ 60–15 mm (Length: 105 mm)
Tube adapter STL 3D file ⌀ 60–15 mm (Length: 105 mm)
Tube coupler ⌀60 mm to ⌀15 mm in STL format. Length of this adapter is 105 mm. The thickness of the tubes is identical: 2 mm. The larger-diameter tube has a sleeve length of 25 mm, the smaller one of 30 mm. The axes of the tubes are off-center by 20 mm. The ends have a fillet on the outside to make tube connection easier.
Parameter Value Unit
side A length 25 mm
side A outer diameter 60 mm
side A thickness 2 mm
side B length 30 mm
side B outer diameter 15 mm
side B thickness 2 mm
transition length 50 mm
axis offset 20 mm
ends fillet fillet on th...

📦 Model #3570

1 object(s)
- format STL
Tube clip holder Ø31 mm STL 3D file · Countersunk screw Ø3 mm
Tube clip holder Ø31 mm STL 3D file · Countersunk screw Ø3 mm
3D model of a Ø31 mm snap-on tube holder in STL format. The fastening is done by means of a flat head screw Ø3 mm. This snap-on tube holder is designed for a secure hold with easy setup.
Parameter Value Unit
tube diameter 31 mm
hole diameter 3 mm
countersunk screw yes

📦 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 #1276

1 object(s)
- format STL
Round air vent STL file ∅ 71.5 mm, slat angle: 40°
Round air vent STL file ∅ 71.5 mm, slat angle: 40°
File of a round air vent for ventilation in STL format. Its male diameter is 71.5 mm. The slats have an angle of 40° and a low thickness of 1.4 mm. This ventilation grille has a thin flange of 5 mm. The overall diameter of this model is 81.5 mm.
Parameter Value Unit
male diameter 71.5 mm
slat angle 40 °
slat thickness 1.4 mm
flange width 5 mm
central reinforcement no

📦 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 #2962

1 object(s)
- format STL
Shelf bracket 100×100 mm STL 3D file, thickness 5 mm, hole diameter 7 mm
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 #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 #1973

1 object(s)
- format STL
Tube adapter STL 3D file ⌀ 60–48 mm (Length: 45 mm)
Tube adapter STL 3D file ⌀ 60–48 mm (Length: 45 mm)
Inline tube adapter ⌀60 mm to ⌀48 mm in STL format. Final length of this sleeve is 45 mm. The thickness of the tubes is identical: 3 mm. The larger-diameter tube has a length of 10 mm, the smaller one of 20 mm. The ends are not rounded.
Parameter Value Unit
side A length 10 mm
side A outer diameter 60 mm
side A thickness 3 mm
side B length 20 mm
side B outer diameter 48 mm
side B thickness 3 mm
transition length 15 mm
axis offset 0 mm
ends fillet no fillet

📦 Model #3362

1 object(s)
- format STL
Protective grid STL file, center-to-center: 65x65mm, mesh: 5mm - Ø4mm
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 #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 #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 #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 #782

1 object(s)
- format STL
Plate STL file 100×12×87 mm
Plate STL file 100×12×87 mm
A 3D STL file of a box. The shape might look like a thin sheet. The overall dimensions are 100×12×87 mm. A small fillet softens all the edges.
Parameter Value Unit
length 100 mm
width 12 mm
height 87 mm
fillet radius 1 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
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 #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 #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

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.