Physics integration with Ogre

[syedhs]

Zero support is okay for me as long as

1) the library matures and has lots of user (which include many AAA games).
2) it is fully documented.

Nobody shouldn't expect a lot (in fact any) of technical support when you pay zero for the library. The next best thing is to have a good Physx board community which is severely lacking.

[CrimsonGT]

Very nice pros/cons listing, thank you for that. Im still fairly hell bent on using Havok, but my lack of experience with implementing/using a physics engine is making it fairly tough. I will probably just wind up going with Newton at this rate (im working on some different stuff while I decide which to go with) due to the lack of a Havok wrapper for Ogre, however it does seem that Havok is a very clean solution to use, especially with the extra tools and what not available.

[betajaen]

The next best thing is to have a good Physx board community which is severely lacking.

The API is pretty consistent in naming and functions, although it has that "C-ish" feel to it. The bundled documentation is pretty good, and they've put back all those tutorial and sample applications that was missing for a few releases, which is great for newbies. I don't really read the NVIDIA forums that much, but from what I've seen there are a number of people who know what they are talking about, other than that you have me.

But nobody should choose a Physics engine because it does more or it's owned by the bigger company. It should be chosen by the required use and scale of the intended application it will be embedded into, and I agree with the OP - He should be using Newton.


Also guys; can we not have a PhysX vs. Havok vs. Newton vs. ODE vs. insert-brand-name-here fest? We've had too many of these already.

[CrimsonGT]

haha I didnt mean for it to turn into that, I was more concerned with which system would fit my needs the best, basically ease of use/integration vs. features.

This is more on a broad note but, coming from a long history of modding source games, if I am using any of these systems, will I need to create a collision mesh for each of the meshes, or just use a simple object? This has really been the number one question in my mind for the past 2 days that im just not really getting. All tutorials, no matter for what system, all use a box or a ball, or capsule, or whatever. If I have multiple players, am I just going to want to use a primitive or is it recommended for improved collision to use a collision mesh? With source when you exported your model file, you also had to export a collision mesh and a skeleton, then compile all 3 into the .mdl file. I was looking through the Havok demos and it showed it reducing the polygons of meshes considerably with code, so im looking for a better of understanding of exactly what I am going to need to do.

[_tommo_]

Zero support is okay for me as long as

1) the library matures and has lots of user (which include many AAA games).
2) it is fully documented.

Nobody shouldn't expect a lot (in fact any) of technical support when you pay zero for the library. The next best thing is to have a good Physx board community which is severely lacking.

Well, i was just expecting it to be as good as when I choose to adopt id
There was no doubt that in mid-2008 PhysX was the best physx engine after Havok, and the best one of the free ones... but then it just stopped development.

I bet that in one year and half of real development, like before Nvidia acquisition, the problems VectreX pointed out would be long gone... they are ruining it for some random marketing, that's it.

[jacmoe]

@Vectrex:
Awesome comparison, thanks a lot!

[syedhs]

There was no doubt that in mid-2008 PhysX was the best physx engine after Havok, and the best one of the free ones... but then it just stopped development.

It has not stopped development, coincidentally I just received an email from NVIDIA PhysX yesterday which points me to this url: http://devsupport.nvidia.com/ics/suppor ... eptID=1949

It is now 2.8.3 but I can see that they highly prioritize the paid-supported programs which is.. expected

[_tommo_]

I know, i already updated to 2.8.3 one month ago
Anyway the changes have been very small and incremental, and mostly to the more-marketed CUDA soft and cloth parts... while i must admit that 2.8.3 looks a bit more stable this time.

[Vectrex]

Physx is good if you want loads of physical objects. It is fast, but you pay for it. Of course if you want fluid or cloth with HW acceleration you don't have much choice in the free market.

[machinimist]

btw, i haven't checked for a while but does physx still not support cylinder collision shapes? what is the reason for that? i think this is a bit of a joke. ode doesn't support stable cylinder collisions either and physx/novodex originally was based on ode so is there something in their technology which makes cylinders impossible to do properly or what other reason could there be that they aren't adding it?

[nullsquared]

If you want to know why Newton is the god of all physics libraries, wait for nullsquared

Very true!

Newton is very stable and easy to use, and supports very heavy customization. This very heavy customization is what allows this:

And the other thing is that Julio (the developer of Newton) is um.... different (and very anti-"self-appointed-physics-experts"), but at the same time he really knows what he's talking about when it comes to physics and provides practically immediate support when you have an issue. And he is constantly updating Newton 2.x, the coming version will have dynamic destruction of initially-static objects.

[syedhs]

btw, i haven't checked for a while but does physx still not support cylinder collision shapes? what is the reason for that? i think this is a bit of a joke. ode doesn't support stable cylinder collisions either and physx/novodex originally was based on ode so is there something in their technology which makes cylinders impossible to do properly or what other reason could there be that they aren't adding it?

It is quite a joke to me too, but honestly if I can replace cylinder with others (such as capsule) and gets the physics behavior about right, who really cares..? I had once worked with ODE and it was such a nightmare to tweak performance and physics behavior (such as object penetration tolerance).

[aimmoth]

How is it with newton and compatibility? I really want good compatibility like Bullet.

Thanks in advance!

[nullsquared]

How is it with newton and compatibility? I really want good compatibility like Bullet.

Thanks in advance!

Compability with what?

[aimmoth]

Like Mac and Linux

[CrimsonGT]

Nullsquared, that is absolutely awesome looking!

I was trying to get the OgreNewt demos to compile as I have decided to definitely go with OgreNewt (thanks to you guys!) but CMake frustrated me, so I just checked out the sourcecode for the ragdoll demo.

The zombie uses a hull.xml and a primitives.xml with the base mesh/skeleton. This is what I have been looking for as I didnt want to just stick my entire player character into a primitive, so I was happy to find an example of using this. Im wondering if theres any tools to create these files (the hull/primitives) from a collision mesh? Also remembered that the source engine compiles the model, the skeleton, and the collision mesh into a single .mdl file. Would this be possible with Ogre without an insane amount of work?

[Vectrex]

If you set the Ragdoll class to use convex hulls it'll generate them dynamically from the ogre mesh skelton, so it's very little work in the xml to set up. Primitives are more fiddly. If you only spawn a ragdoll once in a while it's great, but it's not as fast as the primitives when spawning the ragdoll. But unless you're doing a left for dead style game it won't matter (NOT the australian version though )

[Vectrex]

If you set the Ragdoll class to use convex hulls it'll generate them dynamically from the ogre mesh skelton, so it's very little work in the xml to set up. Primitives are more fiddly. If you only spawn a ragdoll once in a while it's great, but it's not as fast as the primitives when spawning the ragdoll. But unless you're doing a left for dead style game it won't matter (NOT the australian version though )

[CrimsonGT]

I dont actually intend to use ragdolls, death animations would suffice fine, I just felt the ragdoll demo was the closest I have found. I want to use a collision mesh for collisions rather than just primitives, and this is the only example I have seen of actually loading in something similar to this. So OgreNewt can basically generate a simple collision mesh from my skeleton, or am I totally missing something?

[jacmoe]

If you use death animations, you get those funny floating corpses..