Free Online STL to CTM Converter

You can use our STL to CTM conversion tool to quickly and easily convert your 3D model files for free. You may upload up to 20 files at one time, and our batch STL to CTM converter will process each 3D model and present you with a download link for each file once completed.

Select File(s)

Or drag and drop your files here to upload.
A maximum of 20 files can be uploaded at once.

Please note: Your STL file, once uploaded to our server, will be deleted 15 minutes after upload, so please download your converted STL file before this time.

Our 3D model STL to CTM tool will load your STL file and, where supported, attempt to extract all the relevant 3D features, such as geometry, textures, and animations. To access the 3D conversion configuration options, click the button when you have selected your files. The current options support the ability to voxelize your 3D model and more.

How to Convert your STL to CTM Online?

Here are two simple steps to convert your STL to CTM using our fast and free STL converter tool.

Upload your STL file

Click the "Upload a STL File" button, then select a STL to upload. The maximum file size is 100MB.

Download your CTM

Click the download link to receive your CTM file.

Frequently Asked Questions

How can I convert my STL file to CTM?

First, click the "Upload..." button and select your STL file to upload. Your STL file will be uploaded to our servers. When the STL to CTM conversion has completed, you can download your CTM file right away.

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

We aim to process all STL to CTM conversions as quickly as possible; this usually takes around 5 seconds; however, this can be longer for certain files, so please be patient.

How accurate is the STL to CTM conversion?

We aim to provide the best conversion experience. Our tools are under constant review and development, with new features being added every week.

How does converting STL to CTM work?

In order to successfully convert an STL formatted file to the CTM format, our converter tools will perform several initial checks to ensure the file provided is indeed an STL file. There are many files out there where the file type extension does not match the data contained within the file. Along with these file type checks, our tools will do additional checks to ensure the file is correctly formatted to match the provided file type. There are many tools out there that do not always create STL files to the exact specification.

Take your STL file

The STL file format can be either a text-based or binary format, meaning if its content is plain text, it is human-readable; otherwise, if it is binary, then it can only be edited with specialist STL editing software. The data within the file, regardless of whether it is text or binary, is structured in a very simple manner. A 3D model is composed of many triangles, with each triangle comprising 3 vertices. The STL format is simply a sequential list of triangle vertices, which can lead to duplicated data. To guarantee efficient conversions, our tool will check all data that is contained within the STL file and remove any information that is duplicated. This not only ensures the conversion completes more quickly but also that the generated CTM is smaller.

Convert the data from STL to CTM

Now that the data from the STL file has been processed, our tool can apply any conversion specified options, such as enabling Voxel mode, and with these applied, prepare the data to be converted to the final CTM file format. Part of this process ensures checking the capabilities of the CTM format and removing any data that cannot be represented.

Save to the CTM format

At this point, the STL to CTM conversion tool will have the 3D model in a state that is ready to be transferred to the CTM format. Our tool creates the CTM file, ensuring all the model data is present and is formatted to match the CTM file specification to ensure the file opens in compatible CTM file editors.

File format information for STL and CTM

Extension	STL
Full Name	Standard Triangle Language
Type	3D Model
Mime Type	application/vnd.ms-pki.stl
Format	Text
Opens With	Blender, MeshLab, CAD Assistant, DAZ Studio

The STL, or Standard Triangle Language, file format has been around since the '80s and is supported by most modern 3D modelling applications. In particular, the STL format has become something of a standard format within the area of 3D printing, despite the rise of more modern formats such as 3MF.

STL files come in two flavours: binary or text format. The text format is human-readable, making it easy to perform manual edits, but can lead to very large file sizes. As you can imagine, the binary format is much more compact and represents the majority of the STL files you are likely to encounter.

The format itself is very simple; the 3D model is represented by a sequential list of triangles, with each triangle defined with 3 points consisting of their X, Y, and Z positions, along with an additional vector that contains the face normal (the direction the face is pointing). There is an additional attribute block for each triangle; however, this is largely unused and thus unsupported.

STL Converter Capabilities

When converting 3D model or mesh files using our STL converter, we will attempt to convert colour materials into a suitable format for use in the converted file.

Extension	CTM
Full Name	OpenCTM
Type	3D Model
Mime Type	application/x-ctm
Format	Binary

CTM Converter Capabilities

When converting your STL to CTM, our tool will attempt to accurately convert any colour or material information.

Information for converting from STL to CTM

Your STL file will be converted to a CTM file using our unified 3D model and mesh conversion tool. Our STL 3D tool performs accurate conversions of 3D elements such as vertices, faces, normals, and relevant material information. As both STL and CTM support colour material information, our tool will also attempt to convert the colour information.