Open CASCADE, the 3D modelling kernel
3D modeling & numerical simulation



This FAQ is based on real questions answered on our forum

1) Is Open CASCADE Technology license GPL-compatible?

Yes, starting from version 6.7.0 OCCT is released under the terms of the GNU LGPL version 2.1 (and some minor additional permissions), so it is fully compatible with the GNU GPL version 2 and later.

However, OCCT versions 6.6.0 and earlier were released under a custom license (Open CASCADE Technology Public License). That license is similar to the GNU LGPL in terms of purpose and intent, but is incompatible with the GNU GPL.

2) Can I distribute my software product using Open CASCADE Technology under GPL, LGPL or some other license (including proprietary)?

Yes, you can. However, you should always make sure your Final Product license comply with the license requirements of the libraries used in your product. Starting from version 6.7.0, OCCT is released under the terms of the GNU LGPL version 2.1 (and some minor additional permissions), the requirements for software products using the library are described in section 6 of the LGPL text. In case the license of your Final Product is in any conflict with the licenses of the libraries used in it, you need to undertake measures (for example, make appropriate amendments to such Final Product license) to resolve any contradictions.

If in doubt and to avoid possible misunderstandings, please, contact us for advice, we will be happy to answer any questions you may have on this matter.

3) Can I use Open CASCADE Technology to make commercial products and to sell them?
If yes, are there any limitations?

Yes, you can use Open CASCADE Technology (OCCT) libraries in commercial applications without having to pay any development license fees or run time fees or royalties.

Your obligation is to give prominent notice that your software uses Open CASCADE Technology, which is a Trademark of OPEN CASCADE Company, supply a copy of the OCCT license with your product and follow the other requirements of the license itself. Starting from version 6.7.0, this license is the GNU LGPL version 2.1 (with some minor additional permissions).

Please, also note that Open CASCADE Technology uses third-party components which are listed on our System Requirements page. The use of third-party components is governed by their corresponding licenses.

4) If I want to distribute my own software, which uses OCCT, am I obliged to redistribute the whole Installation Package (as available from or I can distribute only the part of the code that I need?

It is allowed and expected that you distribute only the libraries and resources used by your application.

5) Will my usage of OCCT infringe any other licenses or patents?

You do not need any specific arrangements to use any algorithms included into OCCT Open Source distribution.
For many years we have not heard of any patent issues our customers or users had with Open CASCADE Technology.

6) Am I obliged to disclose the entire source code of my application using OCCT?

No, you are not. The decision to disclose the source code of your application is up to you.

7) Is there a Public Bugtracker available to OCC Community?

Yes, Open CASCADE Technology Public Bugtracker is available at
Using the Bugtracker you can report/register bugs you have found and provide bug fixes/patches to the issues reported earlier. The tracker makes the bug advancement process faster, and provides necessary features to track its progress.

Please, note that not all the Bugtracker contents are 100% public since its database contains numerous customer projects that are not available to the general public. Therefore, please, be aware that when you register on the website you will only see public issues and issues related to your own projects.

The Community is always welcome to correct public bugs too! Naturally, we will be happy to integrate such corrections into future public releases.

8) Is there Public Repository for OCCT?

Yes, OCCT Git repository is publicly available. You can browse it online using the GitWeb interface. Note that in order to get read and write access to the repository by Git protocol you should register on OCCT development portal and sign the Contributor's License Agreement; anonymous access is not allowed. See the Resources page on the development portal for more details.

9) I have made a software product using OCCT. How to make it available / known via your site

To present your project, we recommend you to post a new thread describing your project in subsection "Unsorted projects" of the user's forum. You can also ask us to create a dedicated subsection for your project; this can make sense if you expect many threads related to the discussion of your project.

10) Is it possible to contribute to OCCT source code? I have modified OCCT source code and now I should make my modifications available to OCC. How can I do this?

We express our gratitude to all our users who provide us with their modifications.
For more information about how to contribute, please, visit our Collaborative Development Portal and particularly the Get Involved page. You are always welcome to consult the Forum. In case if you are in doubt or have any particular requirements, please send your request using the Contact Form.

11) I would like to know when my contribution / bug correction is integrated in the current development version.

Everyone using Open CASCADE Technology is welcome to contribute to it.
However, you should keep in mind that sending modifications does not automatically lead to their fast appearance in OCCT. Moreover, we do not even commit ourselves to integrating them. Every contribution needs to be first assessed by our experts for its relevance, compliance with other code, coding rules, etc. Additionally, they require non-regression testing and extending of our test base to ensure future non-regression.
So, bug integration is connected with our investments, resource allocation and this can only be done according to our available resources not booked for customer projects.

12) Is it possible to reuse the samples that come with OCCT installation in my own products?

It is exactly the purpose of the standard samples to illustrate OCCT usage and to serve as a basis for your own development. You may reuse these samples freely to create your commercial product.

You should note, however, that the implementation of these samples is focused only on demonstration of a particular functionality and so may be far from optimal. Therefore, if you plan to create a serious professional application, please consider using our support services, in particular, our collection of advanced samples (see details at

13) Can I modify and resell OCCT Products?

No. The Products are advanced components that are provided on a paying basis. Please consult for more information.

14) Is Salome included in OCCT? There is a good feature / solution existing in Salome. Why is it missing in OCCT?

Salome is based on OCCT and developed by our company and our business partners, but it is a separate software integration platform distributed under its particular terms and conditions.
Please, address to for further information.

15) What is the difference between and ?

Website addresses to general public and its purpose is to provide information about OPEN CASCADE Company and promote its offer.
Website is optimized to help the users start their OCCT-based projects, to explain and promote our Open Source software development platform.

16) Can I post messages on the Forum promoting my commercial application based on Open CASCADE Technology?

According to the Forum Rules only single, short announcements of Open CASCADE Technology-based applications are acceptable, but should refer to Web pages for details. Any messages with detailed descriptions or advertisements of commercial third-party applications will be deleted without explanation.

Latest news
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  • Open CASCADE Technology 6.9.0 is available for download!
  • JT Assistant for Android

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