Open CASCADE Technology 6.5 is available for download!


March 5, 2011

OPEN CASCADE S.A.S. is pleased to announce a new public minor release of Open CASCADE Technology & Products (version 6.5). This release introduces about 310 modifications and bug fixes, over previous public minor release 6.3.

Main improvements in this version (a complete breakdown by all versions released since public version 6.3.):

6.3.1 (released on June 19, 2009)

Open CASCADE Technology

- A number of improvements has been made in Foundation Classes and Modeling libraries to facilitate the usage of OCCT in multithreaded applications.
- A mechanism to collect statistics and debug memory allocation with OCCT optimized memory manager has been implemented.
- A basic OCAF toolkit (TKLCAF) has become independent from OCCT modeling libraries.
- Topological naming in OCAF has been considerably improved.
- Geometry construction algorithms have been extended by advanced approximation methods.
- Numerous improvements and bug fixes suggested by OCCT users have been implemented in Visualization libraries.
- New supported compiler: Visual C++ 9.0 (Visual Studio 2008).


- Products have been extended by DRAW Test Harness plug-ins providing commands useful for testing and initial acquaintance with these libraries.

6.4 (released on October 1, 2010)

Open CASCADE Technology

- Accelerated triangulation algorithms in BRepMesh package, due to using Intel® TBB external library for the paralleling tools and the memory manager.
- Use of freetype and ftgl external libraries for advanced 2D and 3D text visualization.
- Improvement of algorithms for line-line, line-plane and plane-plane intersection.
- New quaternion class for definition and manipulation of 3D rotation operators.
- New interactive object class in AIS package for displaying triangulation encapsulated in Poly_Triangulation object.
- List of supported Operating Systems and C++ compilers has been updated. Outdated Operating Systems are no longer supported. Please, see the System Requirements page for details.


- New BestFit product, which computes the transformation minimizing the normal distance between the given cloud of 3d points and the given shape.
- New types of Boolean operations for surface meshes in Open CASCADE Mesh Framework (OMF) product.
- New methods to read and write SAT data to streams in Open CASCADE ACIS SAT Interface product.

6.4.1 (released on February 7, 2011)

Open CASCADE Technology

- STEP interface has been improved to read and write non-manifold topology.
- Trihedron with graduated axes is now available in OCC viewer
- It is now possible to zoom relatively to the current cursor position instead of the view center.
- A new package with Draw commands has been implemented to test Collision Detection product.

6.4.2 (released on February 18, 2011)

Open CASCADE Technology

- FreeImage(Plus) third-party library has been integrated to Open CASCADE Technology.

6.5 (released on March 5, 2011)

Open CASCADE Technology

- Integration of OCCT performance meter.
- Management of presentations by the OCCT visualization engine (TKOpenGL library). has been improved to increase the performance.
- Some memory leaks in OpenGL has been eliminated.
- The definition of dependencies on external libraries has been revised to make them easily configurable.

Detailed information is available in Release Notes ( ).

Release Notes to all previous (customer) versions included into this public release are available for download on our website:

Please, contact us at for any additional information.

Roman Lygin's picture

Congratulations on the release, both the team and the community!

Looking forward to checking if earlier feedback on 6.4.x has been addressed ;-).

jelle's picture

Incredible!!! Congratulation OCC team!!!

Thomas Paviot's picture

Thanks for this very good news! We all here have great expectations after hacking the 6.3.0 release for almost three years.

JuryS's picture

Many thanks ! Congratulations !!!

Fotis Sioutis's picture

Congratulations to the team for the release !

Also could you please provide a download location for the WOK building tool ?

("In 6.4 release notes it has been noted that :
* WOK module will be separated from OCCT libraries and delivered as an independent OCCT building tool.")

IAT's picture

Congrats on your hardwork!


Sharjith Naramparambath's picture

Many thanks for keeping up the spirit of the community :)

kanzure's picture

As Jey/Scott said on 2011-02-24: "We are probably wasting time waiting on this. It has now been several months since the first announcement of the public release 6.4, and subsequent announcements and so on. Could it be that we are not taking a hint here? Could it be that they are nicely saying thanks for being with us but we have to focus on our bottom line here...and we will get back to you when we have time...? I think the response so far seems something along those lines. For any serious open-source commitment you would at least expect periodic updates and bug fixes along any commercial release. The lack of interest in their team can only be interpreted as such - NOT interested at all. I wonder if/when people start looking for alternative development tool and HANDLE things on their own the 2011 way not the 90s. There are a lot of good tools in OCC but there are also things that should be left way back in the 90s. Stuff that seem very cumbersome and in efficient way of HANDLing. My hope was that in current release all that has been given a serious facelift. If it is just a minor stuff here and there I would say it could be about time to move on."

"I agree with Jay's comments on Handles, the whole memory management complication/sophistication of OpenCascade seems to impede progress and development of much more useful higher level functions. It is an approach clearly rooted in the 90's when memory was a much greater concern than it is now. I am not supporting in anyway "Fat" programmes but maybe the balance of development effort is being distorted by this HANDLE based platform. Just look how many questions there are on the forum about interfacing to managed languages like C# and Java. I am seeing a lot of Java based tools that seem to do some of the OpenCascade functions. The main problem I have is with the speed and instability of OpenCascade Boolean operations and I was hoping some of the good work pioneered by Ronan would find its way into the next release. Lets hope it does, but in the meantime are there any suggestions for BREP platforms that can do Boolean Operations and are Open Source?"

P Dolbey's picture

If you run the mfc demos "out of the box" and get an error like

"The application as failed to start because its side-by-side configuration is incorrect. Please see the application event log for more detail."

you may need to download the following VC2005 SP1 redistributable

This will enable to have the 8.0.50727.4053 version of MFC which is required by the pre-compiled binaries. Some of may have moved forward to VC2008/2010 and may not have had this update from Microsoft (well I didn't).

However seeing that there's more flicker than a starlet's eyelids in the Qt demo when window is resized, I feel that there may be a need for getting the box of patches out again, so not much call call for precompiled versions :)


p.s. Whatever happened to OCC 7.0 ?

Andrey Betenev's picture

Hello Pete,

> p.s. Whatever happened to OCC 7.0 ?

Nothing except that this release has been numbered 6.5 instead of (once anticipated) 7.0.
The reason of using number 6.5 is just that the kind of changes we have in this release seem to not justify major number change.
Nevertheless, this version is the best that we have by the moment, and there is no other better version of OCCT hidden under the table.


jelle's picture

Exciting that this release finally came about Andrey!

Venugopal Gudimetla's picture

Thank you very much. After linking my app with 6.5 on Ubuntu 10, the first thing I observed yesterday night was, the Trihedron axes text has disappeared. Not sure of the reason why.


Timo Roth's picture

The link to the release notes of 6.5 on the News-page is wrong. It points to 6.4.2

heXus's picture

YES!!! Thank you very much!!!