Why OCE and not OCCT

[Stephl]

Hey Forum,

I'm totally new to FreeCAD and think this is a very interesting application / open source project!

I spent the last days with homebrew, git, clang,... trying to compile FreeCad on my mac.
Then I stumbled across OCE and OCCT. I didn't know about these libs before. I was wondering why FreeCAD is using OCE and not OCCT. Is there a specific reason for this? I'm just curious...

Regards
Stephan

[jmaustpc]

Your first post, welcome to FreeCAD.

I was wondering why FreeCAD is using OCE and not OCCT.

In simple and general terms, there was considerable frustration in the opensource world with some of the practices of the company behind OCCT and hence OCE was created. At one time OCE was a lot more advanced, it had code that was not accepted by OCCT due to licence/legal reasons but also OCCT was only releasing a version that was very old. In most ways the OCCT company eventually listened and responded to most of the concerns of the opensource community and mostly repaired its relationship by improving its practices.

[Stephl]

Wow, that was a fast answer! Thank you.

So I understand, that from today's perspective it is more or less based on historical events and not sooo much on functionality?

[tanderson69]

At one time OCE was a lot more advanced

This is overstating the situation. OCE got started as a repository for bug fixes that weren't making it back into occt. For me the biggest advantage of oce is, they added cmake support. Installation from source code works very smooth on my system.

[yorik]

I also like OCE more because they made it much more friendly to the linux ecosystem (cmake, debian packaging stuff, etc). But indeed in terms of functionality, nowadays there is basically no difference. There used to be, though, I remember at some point some noticeable bugfixing had been added to OCE... I believe that is what triggered the panic button at OCCT and made them play the game better.

[jmaustpc]

At one time OCE was a lot more advanced

This is overstating the situation. OCE got started as a repository for bug fixes that weren't making it back into occt. For me the biggest advantage of oce is, they added cmake support. Installation from source code works very smooth on my system.

yes, but I was trying summarise a history into a very short, quick, simplified forum post!

But then a "lot more" is of course a somewhat personal and inaccurate unit of measure! ....I would argue that the Cmake support alone makes it "a lot more better"

But also remember how OCCT used to only release major versions to opensource but if you paid then they would give you new versions regularly, or something like that, ...at one point the last opensource version had become very old, and the opensource world was becoming frustrated with not getting a bug fix from was it 3 or 2 years before? or perhaps it was only 18 months, but whatever it was it was not taking advantage of the power of many eyes of opensource.

The other cool thing about OCE was all their experimental and testing branches you could download with GIt and easily help test. You can do so anonymously, although thanks to spam obviously one has to log in to write to a forum etc.

Also OCCT still greatly annoys me because they do not allow anonymous git downloads of the source code! Why not? what possible reason could they have? controlling uploads obviously makes sense but I strongly object to being forced to create an identity on their system and log in just to download their git master branch of opensource code...it really annoys me.

Some of the code in OCE can never be pushed to OCCT because of added some what controversial restriction on top of licence required for them to accept your code, in short you have to "assign" all rights to your code to them.

[ezzieyguywuf]

So does FreeCAD use OCE or OCCT? I've been building it with OCCT, lol.

[sgrogan]

So does FreeCAD use OCE or OCCT? I've been building it with OCCT, lol.

FreeCAD can use either. Historically FreeCAD has been distributed with OCE because of the reasons outlined in the previous posts. Recently OCE has begun to lag OCCT so we are working on moving to OCCT 7.0. (FreeCAD already has the support just the packaging needs to be upgraded)

[ezzieyguywuf]

Ah hah, I see. Thanks for the info.

[NormandC]

Recently OCE has begun to lag OCCT so we are working on moving to OCCT 7.0.

I don't know if you follow the oce-dev mailing list, there's been some recent activity. For starters, Thomas Paviot has proposed to merge tanderson69's occt 6.9.1 branch. But I doubt they will publish an OCCT7-based version anytime soon...