Jan 23, 2011 at 1:49 AM

No one can use this engine with any ease because it contains Bepu which is a paid for physics engine, also bepu is undergoing a major rewrite at the moment so that could change things alot in the future.

I would go with Jitter, BulletX or JigLibX which are all free now and have source code so you could actually modify/intergrate one into your engine...

If this engine has bepu even in it this means that any comercial application cannot use your engine without having to pay royaltys.

Other than that huge problem the engine looks pretty good.

Jan 23, 2011 at 4:33 AM

BEPU charges like %4 of royalties. I think that's quite reasonable. Why do you say it's a huge problem?

Either way, it would take only a few days of hacking to replace Xi's use of BEPU with another physics engine. If you'd like to hack it up and submit a patch, I'd be happy to look at it.

But as a default, I think the advantages that BEPU has over all the other physics engines outweighs it's drawbacks. Maybe you're overreacting a bit?

Jan 23, 2011 at 4:47 AM


It doesn't really matter if its 4% or 0.1% its the fact that people cannot freely use this engine you have developed and if the Bepu licence changes (which it is undergoing now) then you are also bound by any new royalties, some of the changes are going to be a mandatory splash screen and a few other things...

Also many projects (or there project managers etc...) just cannot give any royalties to anyone as they are under a contract that forbids it.

Also this means that anything made with your engine would have to have a contract signed over it with the owner of Bepu (goes by Norbo on the forums) before the game/app can even be sold.

Also many people will not respect the copyright of Bepu and may just put there game up with no one knowing that it even uses Bepu so Norbo will get none of the 4% he deserves

Also according the Bepu licence what you are doing is technically illegal as you cannot bundle his paid dll's with a engine that can be used for commercial use.

I love Bepu and use it heaps but I think that Jitter (which under most circumstances performs better that Bepu at the moment anyway) would be a much better physics engine for this project, Bepu is amazingly powerful and supports almost everything you could want (has over 35 joint types etc...) and while Jitter is a little less huge (only has the 7 most popular joint types) it is easier to use and faster for rigid body collisions.

I talk to Norbo every few days so I will ask him what he thinks of this type of bundling of his engine.
I think he will say that its ok but as long as you don't ship the Bepu dll's with the engine and link them to his site to go get them. (Unless you already do this)

Anyway not having a go at you as your engine looks very cool, but many people will not be able to use it because of these restrictions.

Jan 23, 2011 at 4:58 AM

I've talked with Norbo over the past months and he's not raised any issues with my distribution AFAIK.

But, I do see what you are saying about software that is developed under restrictive contracts. Sad hearing about BEPU requiring a splash screen too.

At any rate, I am willing to change physics engines if a clear winner arises, but in the general case, it still feels murky.

Thanks for raising the issue though - I will be looking into it.

Jan 23, 2011 at 5:03 AM

No problems

Personally I always liked Bepu the best, then Jitter became free just to confuse me more... Then Matali released it's first actual release and my god it's fast (up to 10 times faster than bepu and far more stable with more features) and then to top it all off Digitial Rune physics just came out a few weeks ago too and it is also around 5 times faster than bepu and jitter but costs $200 upfront (but with unlimited uses)

There is also about 4 or 5 open source ones with JigLibX being the best but they are all unsupported and more buggy...

Have you looked at Digital Rune Physics Or Matili Physics? If so what did you think?

Jan 23, 2011 at 5:13 AM

I've looked at them and found them very exciting. I will be looking at them more in depth as I get the chance. I just wish I had more time to devote to testing them and making sure they behave well on the Xbox.

Mar 14, 2011 at 12:25 PM

Bepu is now open source with an Apache 2.0 License and no more royalty fees. It is now hosted under codeplex.