Frequently Asked Questions

About The Exchange

What is the NIH 3D Print Exchange?

The NIH 3D Print Exchange (the “Exchange”) is an open, comprehensive, and interactive website for searching, browsing, downloading, and sharing biomedical 3D print files, modeling tutorials, and educational material. "Biomedical" includes models of cells, bacteria, or viruses, molecules like proteins or DNA, and anatomical models of organs, tissue, and body parts. 

Why did you create the Exchange?

We wanted more people to use 3D printing for science, but we couldn’t find a resource dedicated to that. We had a lot of scientific models at that we knew other people could benefit from, but we didn’t have a good way of making them available.

Who should use the Exchange?

Everyone! The Exchange caters to a wide variety of users with varying levels of experience with 3D prints. It is particularly meant for:

  • Researchers – scientific and clinical researchers will benefit from visualizing molecules, organisms, and anatomical parts
  • Educators and students – the Exchange will provide models that are useful as hands-on teaching aids, and some models will have supplemental materials for teachers to use in the classroom
  • Presenters – anyone presenting on biomedical or bioscientific work who wants to help their audience visualize the concept they are communicating
  • 3D printing enthusiasts – the exchange offers tools that allow users to easily generate and refine models from a wide range of file types.

How is the Exchange different from other online site for sharing 3D printable models?

The NIH 3D print Exchange is unique because:

  • It is the only resource dedicated specifically to bioscientific 3D prints.
  • It is the first government-sponsored website dedicated to 3D printing.
  • It includes new, sophisticated, and free tools to convert scientific data into printable objects in only minutes.
  • We include tutorials to help users learn to make their own 3D prints with 3D modeling software.
  • Part of our mission is dedicated to advancing the use of 3D prints in STEM education, so we will encourage users to add classroom worksheets and other supplements so that the prints can be used as hands-on teaching aids.

The Basics of 3D Printing

What sort of materials are available?

There are many different kinds of materials and technologies used in 3D printing. Some are:

  • Plastic – uses a nozzle like a glue gun to melt plastic into thin filaments that are layered (aka thermoplastic extrusion, fused deposition)
  • Binder jetting – uses a bed of plaster powder where an inket-style print head lays down binding solution (similar to superglue); alternates layers of powder and binder
  • Metal – many ways to use different metals, can use heat, lasers, electron beams.
  • Stereolithography – uses resin that is layered and cured by lasers or lights

What file formats are used in 3D Printing?

The most common and universal file formats for 3D printing are STL and VRML. STL stands for “stereolithography” – it is a 3D rendering that contains only a single color. This is typically the file format you would use with desktop 3D printers. VRML (“vermal”, .WRL file extension) stands for “Virtual Reality Modeling Language” – it is a newer digital 3D file type that also includes color, so it can be used on desktop 3D printers with more than one extruder (i.e. two more nozzles that each can print with a different color plastic), or with full-color binder jetting technology.

Additive Manufacturing File Format (.AMF) is a new XML-based open standard for 3D printing. Unlike STL, it contains support for color. They can also be compressed to about half the size of a compressed STL file. AMF is not widely used at present, but in future we would like to add this an option for uploading and downloading files to and from the NIH 3D Print Exchange.

Another file format input for 3D printers in GCode. This file contains detailed instructions for a 3D printer to follow for each slice, like the starting point for each layer and the "route" that the nozzle or print head will follow in laying down the material. In addition, 3D printer manufacturers may have their own proprietary input file formats that contain instructions specific to the methodology for that make or model, and that are compatible only with that manufacturer's software. This does not create a barrier to printing with these machines, as the proprietary file format is generated from the user's own STL or WRL file. Some examples include the .form file, used with the PreForm software for Form1 printers, or the .zpr format, proprietary to the ZPrint and ZEdit software used with ZCorp binder jet printers.

How do 3D printers work?

3D printers create solid objects by building up thin layers of material (such as different types of plastic); think of a normal printer printing a “stack” of paper but in a predefined shape – it can be solid or hollow, and sometimes needs support scaffolding to hold up pieces of the print when printing.

Appropriate Content

What’s this I hear about people 3D printing weapons? What if people post these or other inappropriate models to the Exchange?

Just about anything can be 3D-printed, and our focus is only on those items that are bioscientifically relevant, such as models of molecules, organs, and lab equipment. We moderate our content regularly to prevent inappropriate material from being shared, and will remove users should we find that they’re misusing the resource.

Contributing Content

How can I contribute to the database?

Only registered users can share models using the “Share” page from the main menu. Registration is free and open to everyone. Once you are registered and logged in, you can upload 3D-printable file content using the "Share" page features, or have tools available the NIH 3D Print Exchange website automatically generate this content using the "Create" page features, including creating 3D-printable files from raw data or from database accession codes from the Protein Data Bank (PDB) and Electron Microscopy Data Bank (EMDB). (More information about PDB and EMDB submissions can be found here.)

Who can use the models I share on the database?

All users can download models on the database; most are freely available to use in whatever way you’d like, but some authors might want to protect their models with Creative Commons licenses to define how others can and cannot use their models. All models submitted by NIH and other government agencies are public domain, and have no restrictions.

Can I protect my model with a license or copyright?

When sharing a model on the database, you can select a Creative Commons license to allow or restrict how users can share, remix, or modify your models. At this time we do not allow users to reserve copyright on their models, to facilitate open science and open data sharing.

What if my model isn’t ready to print in 3D?

As a registered user, you can upload your file on the “Create” page. Our free, online web tools will automatically convert your file to a format that is readily compatible with 3D printers.

What is a Version? What is a Remix?

This is a new feature as of January 13, 2015.
Updated information and help instructions coming soon.

Creating 3D Models

How do you protect my medical imaging scan data when I upload a DICOM?

DICOM-formatted files of medical imaging scans (e.g. CT, MRI, PET, etc.) may contain personal information. To protect your privacy, DICOM files are destroyed once they are converted to 3D-printable STL format, and the raw DICOM image stacks are not stored in our database.

What software can you use for 3D printing?

Blender, SketchUp, OpenSCAD, Netfabb basic, and FreeCAD are among the free, open source modeling software that you can use to design 3D models. Visit our page with Additional Resources to learn more.

PubChem Error: No 3D Conformer Available

PubChem generates theoretical 3D confomers using a program called Omega, and the NIH 3D Print Exchange draws that information from PubChem to generate a 3D model.  Conformer generation is computationally intensive, and PubChem cannot generate 3D conformers for large and complex chemical structures.  This effects approximately 12% of all PubChem entires.  You can still generate a 3D model of the molecule using a workaround; download the 2D SDF of the molecule from the PubChem site, use Omega or Avogadro software to attempt a 3D reconstruction, export a 3D file in CIF, MOL, PDB, or SDF format, and upload the file to the 3D Print Exchange using the Create Page.

Printing Models

Okay – I’ve downloaded a model file from the site…. Now what do I do?

Model files are downloaded in STL or VRML (pronounced “vermal”, has a .WRL extension) format. These formats are what most 3D printers on the market use to print models in and is what these printers [names of what we have at the festival] used to print these examples.

I don’t have a 3D printer but it would be great to have a printed model from your site. What should I do?

We don’t offer general printing for the public, but there are plenty of online or brick-and-mortar stores to choose from. You can also check your local library or area schools.

What is AstroPrint?

AstroPrintTM is a free service that allows you to process, store and access your 3D models in the cloud. When you upload a model to AstroPrint, it generates support material and slices the model to create G-Code for 3D printing. This code is stored in the cloud, and can be streamed to a local printer through any web enabled mobile device (laptop, iPad, cell phone, etc). This way you can have your models ready to print anywhere you go. You can also monitor your 3D printer and organize your designs in the cloud. The NIH 3D Print Exchange is integrated with AstroPrint. If you want to use the service, go to the download menu on the exchange, and click the arrow below AstroPrint icon next to the model you're interested in. You will be prompted to sign in to your AstroPrint account, and if you don't have an account, you can create one in that dialog box. Your models will be sliced and stored in your account on the AstroPrint cloud, so that you can access and print them from any device connected to the web

Additional support can be found in the AstroPrint FAQs.

What is netfabb?

When a 3D model is created, there can be errors that will prevent it from printing properly.  Holes in the mesh, inverted normals, unconnected borders, and intersecting faces can all cause print failures.  To increase the printability of models on the 3D Print Exchange, we have partnered with service called netfabb, which cleans and repairs 3D models.  When you upload or create models on the Exchange, they are processed by netfabb in the cloud.  Netfabb works by running an analysis on the model, and then performing steps to repair any problems it finds.  Netfabb will fill holes, correct triangle orientation, merge close borders, delete redundant and degenerate faces, and remove self intersections.   A resulting model that is verified as clean, watertight and printable is returned to the Exchange, and is made avaliable for download on the model page.

Interactive 3D Viewer

Do I need to install any software on my device to use the interactive viewer?

No. We’re using technologies called WebGL and X3DOM (pronounced X-Freedom) that are designed to work in modern web browsers without special software. However, It’s possible that some web browsers won’t display the content in 3D-viewable format automatically. Try using later versions of Firefox or Chrome, if possible; if that doesn’t work, contact us at 3Dprint@nih.gov and we can help you to troubleshoot so you can manipulate the models on the screen.

How do I know if my browser supports WebGL for viewing models in 3D?

Click here to test your browser for WebGL compatibility.

How do I enable WebGL in Safari?

Although Safari supports WebGL, it isn't enabled by default.

To enable WebGL in Safari, there are three steps:

Open the Safari Preferences (Safari > Preferences…).
Click on the "Advanced" tab and check the box for "Show Develop menu in menu bar" (see "advanced" screenshot).
Enable WebGL in the Develop menu (Develop > Enable WebGL; see "WebGL" screenshot).

You may have to refresh your page. You can also go back and hide the Develop menu after you enable WebGL.

What is WebGL?

WebGL is a cross-platform, royalty-free web standard for viewing 3D graphics in a web browser. WebGL technology allows users to view interactive 3D content without the need to install a special plugin. Visit the WebGL home page to find more.

What is the X3D file format? How can I use it?

X3D is a XML based format for representing and communicating 3D information.  It is an improved version of the VRML (or WRL) format and shares many similarities.  X3D is used for 2D and 3D graphics, 3D viewers, animation, computer assisted design, navigation and much more.  X3D is used on the 3D Print Exchange as an effictive way to preview models before you download them.  We use an embedded viewer called X3DOM that allows models to be visualized in a web browser.  You can download X3D files of the models on the exchange from the download menu, and then import them into 3D software such as Blender or Meshlab.  An advantage of X3D is that, unlike STL, it encodes color information, so downloading the X3D file is essential if you are going to print your model on a color 3D printer.  You can also use downloaded X3D files for displaying 3D models elsewhere, such as your own site, by embedding them into an X3D viewer.

Information for NIH staff

Is there a printing service at NIH?

The NIH Library, based in Building 10 on the NIH main campus, hosts a 3D Printing service through its Technology Sandbox. NIH Staff can contact the organizers to find out more.

How do I find out more information on 3D printing at NIH?

There is a Special Interest Group (SIG) on 3D printing, and you can join the listserv to find out news and events. Search the NIH website to find out how to sign up for a SIG or an email list.

Using the Site

How do I use the "Quick Submit" feature on the Create page?

The "Quick Submit" feature allows you to enter a database accession code for a structure from an external repository to automatically create a 3D-printable file in the NIH 3D Print Exchange. This works for files from (1) the Electron Microscopy Data Bank, or EMDB; (2) the Protein Data Bank, or PDB; and (3) the NCBI PubChem small molecule structure database. Please note that you must have an NIH 3D Print Exchange account and be logged in to use this feature. You can login or create an account here.

  1. For electron microscopy density maps of macromolecular complexes and subcellular structures from the EMDB, you will need to enter the 4-digit numeric code from the file in the EMDB repository, fund in the URL format http://www.ebi.ac.uk/pdbe/entry/EMD-[emdbID]. For example, for the Structure of immature Dengue virus at low pH, we see from the URL and on the resulting page that the accession code is "5006." Enter this code into the Quick Submit box with the drop-down for "EMDB ID" to generate a 3D-printable version of this virus.

  2. For biological macromolecular structures from the PDB, you will need to enter the 4-digit alphanumeric code from the file in the PDB, found in the URL format http://pdb.org/pdb/explore/explore.do?structureId=[pdbID]. For example, for the Plasmodium falciparum dihydroorotate dehydrogenase with a bound inhibitor, we see from the URL and on the resulting page that the accession code is "1TV5." Enter this code into the Quick Submit box with the drop-down for "PDB ID" to generate a 3D-printable version of this structure.

  3. For small molecule structures from PubChem, you will need to enter the numeric chemical ID ("CID"), which is an integer between 1 and 8 digits. This can be found in the URL format https://pubchem.ncbi.nlm.nih.gov/compound/[CID]. For example, for theobromine, we see from the URL and on the resulting page that the CID is "5429". Enter this code into the Quick Sumbit box with the drop-down for "CID" to generate a 3D-printable version of this structure.

Which Internet browsers are supported?

Some features of this site, such as 3D model viewing, leverage technologies such as WebGL that are only possible with modern web browsers. See http://get.webgl.org/ to determine whether your browser supports WebGL.

The NIH 3D Print Exchange recommends using recent versions of Firefox, Chrome, or Safari. Please note that Safari users may need to enable WebGL by first displaying the "Develop" tab (under "Preferences" > "Advanced" > "Show Develop menu in menu bar"), and then clicking "Enable WebGL" in the newly-displayed "Develop" menu in the top menu bar. While the site has not been optimized for Internet Explorer, most features should work using Internet Explorer 11.