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Convert Your 3D Mesh/Model U3D Files to STL

Our free and fast tool will convert your 3D U3D (Universal 3D) model files to a standard STL (Standard Triangle Language) file that can then be edited further in most popular 3D editing packages or 3D printed without any further processing. Our conversion tool can also batch convert multiple U3D files; up to 200 files at a time can be converted.

To convert your U3D file, click the Upload button above and select the file to convert. Once selected, the file will be converted to a STL file and will be ready for download shortly afterwards. For more information about the U3D to STL conversion process, see the conversion information section below.

How to Convert your U3D to STL Online?

Here are two simple steps to convert your U3D to STL.

Upload a U3D File

Click the "Upload a U3D File" button and select a U3D to upload. The maximum file size is 100MB.

Download your STL File

Click the download link once completed to receive your STL file.

File Format Information for U3D to STL

ExtensionU3D
Full NameUniversal 3D
Type3D Model
Mime Typemodel/u3d
FormatBinary
ToolsU3D Converters, 3D Model Voxelizer, Create U3D Animation

Description

The U3D file is a 3D file format (Universal 3D) developed by a consortium of well-known companies in 2005 with the idea of creating a standardized file format for storing 3D data, including mesh vertices, textures, bones, and effects.

U3D files are binary in nature, containing a block-based structure that, following later revisions, could be extended with custom blocks.

ExtensionSTL
Full NameStandard Triangle Language
Type3D Model
Mime Typeapplication/vnd.ms-pki.stl
FormatText & Binary
ToolsSTL Converters, 3D Model Voxelizer, Create STL Animation, Compress STL, Text to STL, STL Viewer
Open WithBlender, Daz Studio, MeshLab, CAD Assistant

Description

The STL file format has its roots in the 1980's and is the native file format for 3D Systems stereolithography CAD software. The format defines a triangulated mesh with vertices and faces and is a popular format for sharing 3D printable model files.

There were several formats that attempted to extend the STL format, namely SolidView and VisCAM, whose formats included limited 15-bit color information for each mesh face, which is often ignored by most modern 3D software. The STL format can be either text or binary; our tools will support both formats.

STL Notes

The standard STL file format does not support colored faces, vertices, or texture information. The STL file generated by the tool will contain only raw mesh/triangle data by default, which is perfect for 3D printing.

The tool also has the option to save the file to one of the non-standard formats that support colored faces, such as VisCAM and SolidView which is perfect if you want to further process the STL in software that supports these formats.

Supported Features

  • Mesh geometry
  • Face colors via the VisCAM and SolidView formats
  • Binary and text versions are supported

Comparing U3D and STL Features

 

U3D Features

  • Mesh Geometry (Vertices and Faces)
  • Vertex Normals
  • Face Normals
  • Vertex Colors
  • Face Materials (Excluding textures)
  • Textures
  • Point Cloud
  • Multiple Objects Per File
  • Object Transforms (Translation, Rotation, and Scale)
  • Bones/Joints
  • Animations
  • Suitable for 3D Printing

STL Features

  • Mesh Geometry (Vertices and Faces)
  • Vertex Normals
  • Face Normals
  • Vertex Colors
  • Face Materials (Excluding textures)
  • Textures
  • Point Cloud
  • Multiple Objects Per File
  • Object Transforms (Translation, Rotation, and Scale)
  • Bones/Joints
  • Animations
  • Suitable for 3D Printing

How does it work?

Converting from the U3D file format to STL can be a complex process, and any tool used for this conversion process needs to be able to handle a variety of data conversion tasks as well as identify any defects within the 3D model and fix them. Here we will explain the conversion process used by our tool to accurately convert your U3D file to a valid STL 3D model. Let's start with the conversion process, which involves the following steps:

Step 1: Read the Source U3D File

In its simplest form, an U3D file is a binary data file containing 3D data such as vertices, faces, normals, and more. When combined, these make up the 3D model you see on your screen.

For more information regarding the U3D file format, please see this great article that goes into a lot of detail explaining the U3D format.

Step 2: Process File Data

With the U3D file data read, our tool generates an internal representation of the full 3D model and will attempt to fix any geometry issues encountered. Along with repairing any issues with the 3D model, the tool will remove any duplicated vertices and prepare the model for exporting to the STL format.

Step 1: Read the Source U3D File

Step 3: Saving to the STL Format

The STL format has been around for many years and has become not only a standard format for storing and transmitting 3D models but also a standard format for 3D printing, something we have talked about previously. STL files can be opened in most modern 3D editing applications without further processing.

To enable the saving of the model, our tool now needs to take the in-memory 3D model we have created in step 2 and convert this to the STL format. As the STL format supports only simple triangles with a single directional normal, if your U3D contains vertex normals, these will be recalculated into a single-face normal. To ensure an efficient file size, our tool will always save any STL file in its binary format.

Converting Your U3D File for 3D Printing

Software used to prepare a 3D model file for printing, which is also known as 3D slicer software, cannot usually open U3D files. This is because slicer software authors will support the most common formats used for 3D printing, such as STL and 3MF and do not have the resources to implement 3D object parsers for all the possible 3D formats that are out there.

A small cog in the U3D format

A small cog in the U3D format

The cog in a Replicator 3D printer

The cog in a Replicator 3D printer

The completed 3D printed cog

The completed 3D printed cog

Slicer software can, however, handle files formatted to the STL specification. This is because STL, although predating the 3D printing revolution and lacking in some of the features of modern formats, has found almost universal adoption as the format of choice for distributing 3D printable models. Our U3D to STL conversion tool can convert your U3D file into an STL file suitable for loading into the 3D slicer software of your choice. As STL files do not support material colors or textures, our converter will not process these, resulting in a single STL file suitable for use with most 3D slicer software.

Frequently Asked Questions

What is an STL file?

The STL file format describes an unstructured triangulated surface of the triangles using a 3D Cartesian coordinate system. STL files do not contain any scale information, and the units are arbitrary. We have a more detailed description of an STL file which can be found on our STL file page.

What STL formats can I convert to?

Our tool will save all STL files in binary format. Optionally, our tool will allow you to save to the non-standard color STL format.

I have several U3D files; can I batch convert my U3D to STL?

Yes! Our U3D tool supports full batch conversions. You can upload up to 200 U3D files at a time. Our tool will convert them all as quickly as possible. Once completed, you can either download the STL files individually or download them all in a single ZIP file.

How can I convert my U3D file to STL?

First click the "Upload..." button, and select your U3D file to upload. You can also drag and drop your file onto the tool. Once your file is selected, you can set any configuration options. When the U3D to STL conversion has completed, you can download your STL file straight away.

How long does it take to convert my U3D to STL?

We aim to process all U3D to STL conversions as quickly as possible, this usually takes around 5 seconds but can be more for larger more complex files so please be patient.

How accurate is the U3D to STL conversion?

We aim to create the most accurate conversions with our tools. Our tools are under constant development with new features and improvements being added every week.

Is it safe to convert my U3D to STL on ImageToStl.com?

Yes, of course! We do not store the U3D file you submit to us. The resulting STL file, once created, is stored for 4 hours after upload; after this time it is deleted, and the short-term download link will stop working. You can create a long-term download Url with most tools that will ensure the file is retained for 24 hours, allowing you to download the file when convenient. Our tools also come with a Delete button, allowing you to delete the file immediately.

Do I need a high-spec. computer to use the U3D to STL converter?

No. All our conversion tools process your U3D file on our dedicated conversion servers, meaning you can use our tools on low-spec computers, laptops, tablets, and mobile devices and receive your converted STL file quickly.

Can I convert my U3D to STL on Windows, Linux, Android, iOS or Mac OS?

Yes! Our U3D to STL tool will run on any system with a modern web browser. No specialist software is needed to run any of our conversion tools.

What if I am using an Ad Blocker, will that affect things?

Yes. Although you can use an Ad Blocker, if you like our U3D conversion tool please consider white-listing our website. When an Ad Blocker is enabled there are some conversion limits and some settings may not be available when using our tools. Processing/conversion and download times will also be longer.

Can I get support with converting my U3D to STL?

Yes. When you have converted your U3D to STL, there is a "Feedback" option that you can use to let us know of any issues you encountered when converting your file.

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