Licensing of OpenCascade

I read through the license.txt file for OpenCascade and it seems to be fairly open for use in commercial applications. The main point of the license seems to be that any modifications/improvements to the OpenCascade code must be made available. Am I understanding this correctly?

Forum supervisor's picture


Yes, that's correct. The license also requires that you acknowledge your software uses Open CASCADE. To do so you need to include the Public License into the distribution package and for example to add this into the About box, etc.

Best regards,
Forum supervisor

Paul Delhanty's picture

Hello Forum supervisor

Can you clarify the part of the clause 4 that reads:

"For greater certainty, it is expressly understood that You may freely create Derivative Programs (without any obligation to publish such Derivative Program) and distribute same as a single product. In such case, You must ensure that all the requirements of this License are fulfilled for the Software or any portion thereof."

Does that means it is OK to create and sell derived programs or modules that link with the Software (Open CASCADE) without publishing the source to the derived portions of the program, as long as one complies with the license conditions regarding the software? (That is acknowledgements as you described, making the Open CASCADE source available, documenting and making the modifications to the Open CASCADE source available etc.)

Forum supervisor's picture

Hi Paul,

Yes, that's right.

Kind regards,
Forum supervisor

ducelierin's picture

Dear forum supervisor,

I am looking for license agreement and previous discution in

As I understand, if we modify OCC to use it inside a commercial product, we must:
- make a copy of Schedule "B" inside our own license agreement.
- make source code modifications available.

My question is : how to make these source code modifications available ?
- Is there somewhere on your site a place where we must upload the modification ?
- Do we give only the source code "On demand". Modifications are provided only to people that have read the license agreement and who ask for having source code modification delivered ?


Forum supervisor's picture

Hello Bernard,

First of all, thank you for your intent to provide us your modifications. Please prepare an archive containing your modifications and send it by email to Please also let us know more about the project you are using Open CASCADE Technology in.

As for Open CASCADE Public License, you may find it

Best regards,
Forum Supervisor

Alex's picture

Dear Forum Supervisor,
What is the license type for the samples that come with occ installation?
Say, if I write a program based on one of the wizard, re-use the source code of the samples (with slight modifications), with the occ library remains unchanged (ie. NO modification is made to occ library). Would this be considered ok if the program is to be a commercial product? Or any particular things that I need to do?

Forum supervisor's picture

Hello Alex,

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

However please note that implementation of these samples concentrates on ease of understanding 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

Best regards,
Forum Supervisor

Alex's picture

Thank you very much for your reply.
Just one more question, when you said 'use them freely', I assume that you meant 'using them freely and without the need to publish/open the source code of the program'.
By the way, I will consider your suggestion. I am currently still doing an assessment of the package.
Thank you.