Changes

There are some important things to note when modeling for 3D printing. It is important to optimize the print by decreasing print time and material while ensuring accuracy and strength of the part.

There are some important things to note when modeling for 3D printing. It is important to optimize the print by decreasing print time and material while ensuring accuracy and strength of the part.

# Divide your model into smaller more manageable parts. There are many designs with complex details or large dimensions that would be more manageable prints if split into multiple parts

# Divide your model into smaller more manageable parts. There are many designs with complex details or large dimensions that would be more manageable prints if split into multiple parts. [[File:Multiple parts 3D print.png|center|thumb|599x599px|3D printed hand built with multiple parts. Finger is attached afterwards. ]]

# Try to ensure that there is one flat surface on the print. This will allow easier print set-up. The flat side can adhere to the build plate, minimizing the need for additional build plate adhesion.

# Try to ensure that there is one flat surface on the print. This will allow easier print set-up. The flat side can adhere to the build plate, minimizing the need for additional build plate adhesion.[[File:Prints in different orientation.png|center|thumb|300x300px|Traffic cone printed in two different orientations. It demonstrates the optimal orientation with the least amount of supports. ]]

# Avoid floating parts. All aspect of the model should be connected to the main model. Minimize overhangs in the model as well. This will prevent wasted time and material to print supports.  

# Avoid floating parts. All aspect of the model should be connected to the main model. Minimize overhangs in the model as well. This will prevent wasted time and material to print supports.[[File:Supports under floating parts.png|center|thumb|480x480px|Printed gearbox with floating parts with supports under them. ]]

# FDM printing has limited capabilities with dimensional accuracy. It is recommended to prevent printing horizontally oriented holes of the smaller size. These holes are often deformed and printed with difficult to remove supports.  

# FDM printing has limited capabilities with dimensional accuracy. It is recommended to prevent printing horizontally oriented holes of the smaller size. These holes are often deformed and printed with difficult to remove supports.[[File:Holes printed vertically and horizontally..png|center|thumb|500x500px|Holes printed vertically on the left and horizontally with the layers on the right. ]]

# Printed parts are stronger in one direction than another. It is important to keep this in mind when designing. Prints will be weaker in the areas where the layers meet. This means that printed parts have low tensile strength along the Z-axis. The prints will be the strongest in planes parallel to the build surface.

# Printed parts are stronger in one direction than another. It is important to keep this in mind when designing. Prints will be weaker in the areas where the layers meet. This means that printed parts have low tensile strength along the Z-axis. The prints will be the strongest in planes parallel to the build surface.[[File:Layers printed in different axis.png|center|thumb|500x500px]]

# Exaggerate the details of your designs. This is an important thing to keep in mind. In order for details to show up on small designs, you should make your cuts deeper and bigger. It can also be helpful to make slender designs thicker.  

# Exaggerate the details of your designs. This is an important thing to keep in mind. In order for details to show up on small designs, you should make your cuts deeper and bigger. It can also be helpful to make slender designs thicker.[[File:Details on 3D prints.png|center|thumb|450x450px|Details on CAD on the left with the same details printed on the right. ]]

# Exaggerate the details of your designs. This is an important thing to keep in mind. In order for details to show up on small designs, you should make your cuts deeper and bigger. It can also be helpful to make slender designs thicker.  

# Round surfaces will not show up smoothly. Since FDM prints in layers, it will cause the rounded surfaces to look jagged. To achieve a smooth surface, additional processing will be required. [[File:3D printed surface .png|center|thumb|449x449px|3D printed surface with all the layers before and after additional processing. ]]

=== [https://en.wikipedia.org/wiki/STL_(file_format) Standard Triangle Language (*.STL)] ===

=== [https://en.wikipedia.org/wiki/STL_(file_format) Standard Triangle Language (*.STL)] ===

STL files are the most used file format in 3D printing and 3D modeling. Most 3D printers support the file format. Many of the 3D printable models online are also found in STL file format. STL stands for stereolithography, a 3D printing process created at 3D Systems in <ins>the </ins>1980s. STL file format encodes the surface geometry of a 3D object. This is done through tessellation, a process of tiling a surface with one or more geometric shapes so there are no overlaps or gaps. The basic method of tessellating the outer surface of 3D models is through the use of tiny triangles (called “facets”) and store information about the facets in a file. For example, in the figure below, it shows how a cube can be represented by 12 triangles while 17000+ triangles are needed to represent a sphere. Since triangles consist of three straight edges, it can be difficult to approximate curved geometries. To do so, mesh density is increased, and individual triangle’s size is decreased.  

STL files are the most used file format in 3D printing and 3D modeling. Most 3D printers support the file format. Many of the 3D printable models online are also found in STL file format. STL stands for stereolithography, a 3D printing process created at 3D Systems in <ins>the </ins>1980s. STL file format encodes the surface geometry of a 3D object. This is done through tessellation, a process of tiling a surface with one or more geometric shapes so there are no overlaps or gaps. The basic method of tessellating the outer surface of 3D models is through the use of tiny triangles (called “facets”) and store information about the facets in a file. For example, in the figure below, it shows how a cube can be represented by 12 triangles while 17000+ triangles are needed to represent a sphere. Since triangles consist of three straight edges, it can be difficult to approximate curved geometries. To do so, mesh density is increased, and individual triangle’s size is decreased.  

STL file format stores the information as the coordinates of the vertices and the components of the unit normal vector to the triangle. The normal vector point outwards of the 3D model.  

STL file format stores the information as the coordinates of the vertices and the components of the unit normal vector to the triangle. The normal vector point outwards of the 3D model.  

 

There are a couple of rules for tessellation and storing information. The vertex rule states that each triangle must share two vertices with its neighbouring triangles.  

There are a couple of rules for tessellation and storing information. The vertex rule states that each triangle must share two vertices with its neighbouring triangles.  

The all-positive octant rule states that the coordinates of the triangle vertices must all be positive. This ensures that all coordinates stored would be in the positive which would save space in the file. Finally, the triangle sorting rule recommends that the triangles appear in ascending z-value order. This is a recommendation rather than a rule as it helps the software slice the models faster.

The all-positive octant rule states that the coordinates of the triangle vertices must all be positive. This ensures that all coordinates stored would be in the positive which would save space in the file. Finally, the triangle sorting rule recommends that the triangles appear in ascending z-value order. This is a recommendation rather than a rule as it helps the software slice the models faster.

=== [https://en.wikipedia.org/wiki/Wavefront_.obj_file Wavefront OBJ (*.OBJ)] ===

=== [https://en.wikipedia.org/wiki/Wavefront_.obj_file Wavefront OBJ (*.OBJ)] ===

OBJ is a crucial file format in 3D printing. It is generally preferred for multi-colour 3D printing. Often, it is used a s an interchange format for non-animated 3D models. OBJ file format stores information about 3D models by encoding the surface geometry of the model. It also stores information about its colour and texture. It does not store any data about animations or scene. It is open source and neutral. Therefore, it is often used to share 3D models since many CAD software supports the format.

OBJ is a crucial file format in 3D printing. It is generally preferred for multi-colour 3D printing. Often, it is used a s an interchange format for non-animated 3D models. OBJ file format stores information about 3D models by encoding the surface geometry of the model. It also stores information about its colour and texture. It does not store any data about animations or scene. It is open source and neutral. Therefore, it is often used to share 3D models since many CAD software supports the format.

 

It differs from STL since it stores colour and texture information. STL is an older file format that is missing modern features. It does not support multi colour printing or high resolution prints. OBJ can approximate surface geometry well without drastically increasing the file size. It also supports multiple colours and textures in the same model.

It differs from STL since it stores colour and texture information. STL is an older file format that is missing modern features. It does not support multi colour printing or high resolution prints. OBJ can approximate surface geometry well without drastically increasing the file size. It also supports multiple colours and textures in the same model.