3d Software Stl File Format
Understand the STL resolution The STL file format uses a series of linked triangles to recreate the surface geometry of a solid model. When you increase the resolution, more triangles will be used, approximating the surfaces of the 3D model better, but also increasing the size of the STL file. A sphere rendered in three different resolutions in MeshMixer If you export in too low of a resolution, the model will have visible triangles on its surface when it is printed. Most of the times this is undesirable, but it can be exploited to create 'low-poly' models with a digital look. Increasing the resolution above a certain point is also not recommended, as it brings no additional benefit: very fine details cannot be 3D printed, so the size of the file will be unnecessarily increased, making it more difficult to handle and process. A low resolution sphere: The triangles are affecting the shape. Choose the right exporting parameters You can change the resolution of your STL files by altering the tolerance in your CAD software.
To export your model go to File > Export and select the.stl file format. Use 3D modeling software that lets you. Repair STL Files' by All3DP is licensed. The STL file format. 3D Systems delivers hardware that scans in 3D. Experience true productivity with exclusive additive manufacturing software for 3D Systems.
When unsure, selecting the 'high' preset is the safest option for generating an STL file that is suitable for 3D printing. Each CAD package has a different way of specifying the STL resolution, but most use two main parameters: chord height and angle. The chord height is the maximum distance that your software will allow between the surface of the original 3D model and the surface of the STL file. Using a smaller chord height will help represent more accurate the curvature of a surface. The recommended value for the chord height is 1/20th of the 3D printing layer thickness and never below 0.001 mm (1 micron). This will always result in an STL file with ideal accuracy for most 3D printing applications.
Exporting in a smaller tolerance will not have any effect in the quality of your print, as most common 3D printers are not able to reproduce such a high level of detail. A visual illustration of chord height The angular tolerance limits the angle between the normals of adjacent triangles. The default setting is often 15 degrees. Some software also specify this tolerance as a value between 0 and 1. Unless a higher setting is necessary to achieve smoother surfaces, the default value of 15 degrees (or 0) is recommended.
A visual illustration of angular tolerance Step 3. Export STL files from your CAD software All CAD software have their own way to export STL files. Use the following table as a quick reference: Software Description Solidworks File Save As. File type to STL Options Resolution Fine (or Custom) OK 3DS Max 3DS Max Application Menu Export StereoLitho (.STL) AutoCAD Output Send panel Export At the Command prompt, enter export.
In the Export Data dialog box, enter a filename. Under Files of Type, select Lithography (.stl) and click Save. Select one or more solid objects. Note: The XYZ coordinates of all objects must be above zero. The file extension.stl is automatically appended to the file name.
Fusion 360 File 3D Print Under Refinement / Refinement options, select export settings. Output untick “Send to 3D Print Utility” OK Save Inventor File Print 3D Print Preview Save Copy As.
(top left of window) Save Onshape Right click on Part Name on bottom right Export Under Format, select STL. Specify model units. Select export settings. PTC Creo File Save As. Save a Copy Change Type to Stereolithography (.stl).
Click OK a new Export STL dialog will open. Under Deviation Control, change export settings. Rhino File Save As In the Save As. Box, select Stereolithography.stl. Sketchup Download plugin. Start Sketchup.
Tools Export to DXF or STL Solid Edge File Save As. File type to STL. Options Select export options ZBrush Use Decimation Master to appropriately reduce the polygon count.
Zplugin 3D Print Hub Export as STL. You can learn more about the different types of CAD software for 3D printing in of the Knowledge Base. Rules of thumb. Export with a 0.001 mm chord height and 15 o angular tolerance for best 3D printing results. Avoid exporting unnecessarily large STL files.
and we will auto-fix small geometry imperfections.
In a nutshell, an STL file stores information about 3D models. This format describes only the surface geometry of a three-dimensional object without any representation of color, texture or other common model attributes.
These files are usually generated by a computer-aided design (CAD) program, as an end product of the 3D modeling process. STL” is the file extension of the STL file format. The STL file format is the most commonly used file format for 3D printing.
When used in conjunction with a, it allows a computer to communicate with 3D printer hardware. Since its humble beginnings, the STL file format has been adopted and supported by many other CAD software packages, and today is widely used for rapid prototyping, 3D printing, and computer-aided manufacturing. Hobbyists and professionals use it alike. What does the file extension.STL stand for?
The true meaning of the file extension.STL has been lost to the mists of time. It’s widely believed to be an abbreviation of the word STereo Lithography, though sometimes it is also referred to as “Standard Triangle Language” or “Standard Tessellation Language”. How does the STL file format store a 3D model? The main purpose of the STL file format is to encode the surface geometry of a 3D object.
It encodes this information using a simple concept called “tessellation”. 3.1 Tessellation Tessellation is the process of tiling a surface with one or more geometric shapes such that there are no overlaps or gaps.
If you have ever seen a tiled floor or wall, that is a good real life example of tessellation. The basic idea was to tessellate the 2 dimensional outer surface of 3D models using tiny triangles (also called “facets”) and store information about the facets in a file. Let’s look at a few examples to understand how this works. For example, if you have a simple 3D cube, this can be covered by 12 triangles, as shown in the image below. As you can see, there are two triangles per face. Since the cube has six faces, it adds up to 12 triangles. If you have a 3D model of a sphere, then it can be covered by many small triangles, also shown in the same image.
Tessellation of a 3D pig (source: i.materialize) The Albert Consulting Group for 3D Systems realized that if they could store the information about these tiny triangles in a file, then this file could completely describe the surface of an arbitrary 3D model. This formed the basic idea behind the STL file format! How does an STL file store information about facets? The STL file format provides two different ways of storing information about the triangular facets that tile the object surface. These are called the ASCII encoding and the binary encoding. In both formats, the following information of each triangle is stored:.
The coordinates of the vertices. The components of the unit normal vector to the triangle. The normal vector should point outwards with respect to the 3D model. Foreach triangle REAL323 – Normal vector REAL323 – Vertex 1 REAL323 – Vertex 2 REAL323 – Vertex 3 UINT16 – Attribute byte count end Note that after each triangle, there is a 2 byte sequence called the “attribute byte count”. In most cases, this is set to zero and acts a spacer between two triangles. But some software also use these 2 bytes to encode additional information about the triangle. We will see such an example later, where these bytes will be used to store color information.
Special rules for the STL format The STL specification has some special rules for tessellation and for storing information. 5.1 The vertex rule. The all positive octant rule says that the coordinates of the triangle vertices must all be positive. This implies that the 3D object lives in the all-positive octant of the 3D Cartesian coordinate system (and hence the name).
The rationale behind this rule is to save space. If the 3D object was allowed to live anywhere in the coordinate space, we would have to deal with negative co-ordinates. To store negative co-ordinates, one needs to use signed floating point numbers.
Signed floating point numbers require one additional bit to store the sign (+/-). By ensuring that all coordinates are positive, this rule makes sure that we are able to use unsigned numbers for the coordinates and save a bit for every coordinate value we store. For 3D printing, the STL file has to be opened in a dedicated slicer. What’s a slicer? It’s a piece of 3D printing software that converts digital 3D models into printing instructions for your 3D printer to create an object.
The slicer chops up your STL file into hundreds (sometimes thousands) of flat horizontal layers based on the settings you choose and calculates how much material your printer will need to extrude and how long it will take to do it. All of this information is then bundled up into a GCode file, the native language of your 3D printer. Slicer settings do have an impact the quality of your print so it’s important to have the right software and settings to get you the best quality print possible. Once the GCode has been uploaded to your 3D printer, the next stage is for those separate two-dimensional layers to be reassembled as a three-dimensional object on your print-bed.
This is done by depositing a succession of thin layers of plastics, metals, or composite materials, and building up the model one layer at a time. More information: 7. Is Every STL File 3D Printable? Unfortunately not.
Only a 3D design that’s specifically made for 3D printing is 3D printable. The STL file is just the container for the data, not a guarantee that something is printable.
3D models suitable for 3D printing need to have a minimum wall thickness and a “watertight” surface geometry to be 3D printable. Even if it’s visible on a computer screen, it’s impossible to print something with a wall thickness of zero.
There’s also the consideration of overhanging elements on the model. Look at the ALL3DP logo in the picture above; if the model is printed upright, then overhanging elements with more than a 45-degree angle will require supports (which you can see in green). When downloading an STL file that you haven’t created yourself, it’s worth taking the time to verify that it is indeed 3D printable. This will save you a lot of time and frustration (and wasted filament).
Further reading: and 8. Optimizing an STL file for best 3D printing performance The STL file format approximates the surface of a CAD model with triangles. The approximation is never perfect, and the facets introduce coarseness to the model. The perfect spherical surface on the left is approximated by tessellations. The figure on the right uses big triangles, resulting in a coarse model.
The figure on the center uses smaller triangles and achieves a smoother approximation (source: i.materialize) The 3D printer will print the object with the same coarseness as specified by the STL file. Of course, by making the triangles smaller and smaller, the approximation can be made better and better, resulting in good quality prints. However, as you decrease the size of the triangle, the number of triangles needed to cover the surface also increases. This leads to gigantic STL file which 3D printers cannot handle. It’s also a pain to share or upload huge files like that.
It is therefore very important to find the right balance between file size and print quality. It does not make sense to reduce the size of the triangles ad infinitum because at some point your eye is not going to be able to distinguish between the print qualities. Most CAD software offer a couple of settings when exporting STL files. These settings control the size of the facets, and hence print quality and file size. Let’s dig into the most important settings and find out their optimum values. 8.1 Chord height or tolerance Most CAD software will let you choose a parameter called chord height or tolerance. The chord height is the maximum distance from the surface of the original design and the STL mesh.
If you choose the right tolerance, your prints will look smooth and not pixelated. It’s quite obvious that the smaller the chord height, the more accurately the facets represent the actual surface of the model. The chord height is the height between the STL mesh and the actual surface (source: www.3dhubs.com) It is recommended to set the tolerance between 0.01 milimeters to 0.001 milimeters. This usually results in good quality prints. There is no point in reducing this any further, as 3D printers cannot print with that level of detail. 8.2 Angular deviation or angular tolerance Angular tolerance limits the angle between the normals of adjacent triangles. The default angle is usually set at 15 degrees.
Decreasing the tolerance (which can range to 0 to 1) improves print resolution. Angular tolerance is the angle between the normals of adjacent triangles (source: www.3dhubs.com) The recommended setting for this parameter is 0. 8.3 Binary or ASCII? Finally, you have a choice of exporting the STL file in binary or ASCII format. The binary format is always recommended for 3D printing since it results in smaller file sizes.
Free 3d Software Stl File Format
However, if you want to manually inspect the STL file for debugging, then ASCII is preferable because it is easier to read. Are there any alternatives to the STL File Format? The STL file format is not the only format used in 3D printing. There are over 30 file formats for 3D printing. Most important is the OBJ file format, which can store color and texture profiles.
Another option the is Polygon file format (PLY), which was originally used for storing 3D scanned objects. More recently, there have been efforts to launch a new file type by, which is proposing a new 3D printing file format called 3MF.
They claim it will streamline and improve the 3D printing process. To implement it, Microsoft has partnered up companies like Autodesk, HP, and Shapeways to make their vision a reality. More details on the 3MF Consortium can be read on their, together with preliminary documentation about the 3MF file type on.
It’s far too early to say whether this will become widely adopted, however. Advantages and disadvantages of using STL file format over other file formats Since there are many 3D printing file formats, the obvious question is: which one should you use for your prints? The answer, as it turns out, depends a lot on your use case. 10.1 When not to use an STL file As we saw earlier, the STL file format cannot store additional information such as color, material etc. Of the facets or triangles. It only stores information about the vertices and the normal vector.
This means that if you want to use multiple colors or multiple materials for your prints, then the STL file format is not the right choice. The OBJ format is a popular format enjoying good support which has a way to specify color, material etc. Therefore, this is the right choice for this task. 10.2 When to use an STL file On the other hand, if you want to print with a single color or material, which is most often the case, then STL is better than OBJ since it is simpler, leading to smaller file sizes and faster processing. 10.3 Other advantages of the STL file format Universal: Another big advantage of the STL file format is that it is universal and supported by nearly all 3D printers.
This cannot be said for the OBJ format, even though it enjoys reasonable adoption and support as well. The VRML, AMF and 3MF formats are not widely supported at this point of time. Mature ecosystem: Most 3D printable models you can find on the internet are in the STL file format. The existence of this ecosystem, combined with STL-based software investments made by 3D printer manufacturers, has given rise to a large user-base that’s heavily invested in the format.
This means there’s plenty of third party software dealing with STL files, which is not the case with the other file formats. 10.4 Some disadvantages of the STL file format There are some glaring disadvantages to using STL as well. As the fidelity of printing processes embraces micron-scale resolution, the number of triangles required to describe smooth curved surfaces can result in massive file sizes. It’s also impossible to include metadata (such as authorship and copyright information) in an STL file. 10.5 Verdict If your 3D printing needs are simple, then perhaps there is no reason to move away from the STL file format.
However, for more advanced prints using multiple material and color, it is perhaps advisable to try the OBJ or other available formats. Color in STL File Format In the last section, we said that the STL file format cannot handle multi-color models.
The reason the STL file format lacks color information is simple. When rapid prototyping evolved in the 1980s, no one thought of color printing. Nowadays, 3D printing materials and processes have evolved rapidly.
Some allow you to print in full-color – just think of sandstone 3D selfies, as pictured above. However it’s not completely fair to say that STL cannot handle colors. It turns out that there are non-standard versions of the STL format that are indeed capable of carrying color information. For example, the VisCAM and Solidview software packages use the “attribute byte count” at the end of every triangle to store a 15-bit RGB color using the following system:. bits 0 to 4 for blue (0 to 31),.
bits 5 to 9 for green (0 to 31),. bits 10 to 14 for red (0 to 31),. bit 15 is 1 if the color is valid, or 0 if the color is not valid (as with normal STL files). The Materialize Magics software, on the other hand, uses the 80-byte header in the binary format to represent the overall color of the 3D object. The color is specified by including the ASCII string “COLOR=” followed by four bytes representing red, green, blue and alpha channel (transparency) in the range 0–255. This base color can also be overridden at each facet using the “attribute byte count” bytes.
STL file resources If you have read so far, congratulations! You now know quite a bit about STL and can be undoubtedly called an STL file format expert.
In this final section, we will share some awesome software and resources that you can use for downloading, viewing, editing and repairing STL files. 12.1 Downloading STL files There are many repositories, marketplaces and search engines on the web containing literally millions of free STL files. You can refer to our regularly updated list — — or you can choose one of these models to get started: 12.2 Opening and viewing an STL file Fortunately, opening an STL file is not too complicated. There are several free STL file viewers for this purpose, which you can either use online or as a desktop application. Refer to our dedicated guide here: 12.3 Editing and converting an STL file Yes, it is entirely possible to edit an STL file and convert the STL file to another file format.
Because the format is open, there is nothing to prevent you from changing the contents of a file. Actually, the process of editing is quite easy. We have a dedicated article on this topic: 12.4 Repairing an STL file Remember the section where we discussed the rules that STL files must satisfy?
For example, adjacent triangles must share two vertices and the right hand rule applied on the vertices should result in the same orientation as the normal vector. If these conditions are violated in an STL file, then it is broken or corrupt. There are several programs which can help with repairing a broken STL file. For example, Netfabb Basic is a great tool for repairing the most common STL file problems. You find more information on these programs in our article: 13. Conclusion In conclusion, we have learned about how the STL file format encodes the layout of 3D models. We discussed how to optimize STL files for the best 3D printing quality.
We talked about how the STL file format compares with the other popular 3D printing file format.OBJ and when to use each of these formats. Finally, we shared some resources using which you can download, view, edit and repair STL files.
We hope that an in-depth understanding of the STL file format helps you become a more knowledgeable user of your 3D printer. If you found this article useful, share it with other 3D printing enthusiasts and spread the word. Do you have some questions or remarks? Let us know in the comments below!