Larian Studios Forums Divinity II The Dragon Knight Saga / Flames of Vengeance (English) Divinity II - The Dragon Knight Saga Nvidia Cuda Physics?

I thought I remember reading that the game used the Cuda physics engine, but I haven't seen anywhere to turn this on or off and haven't seen any indication that it's using CUDA. Is it? Anyplace to verify that it is using it, or that it is working correctly?

Thanks!

I think you're a bit confused. CUDA isn't a physics engine, it's related to the architecture of the GPU (Well, GPGPU now). You're thinking of PhysX, which is nVidia's physics engine that has both software and a hardware-accelerated modes.

To turn PhysX's hardware-accelerated mode off, along with other CUDA-based applications, you need to go your nVidia control panel, select 'Manage 3D Settings' and the sixth option should be 'CUDA - GPUs' and deselect your GPU (Click 'All' and then the tick-box for your GPU). As for PhysX itself, it cannot be turned off. It's as much a part of the game as, say, the lighting. You can toggle between the software mode (i.e. CPU) or the hardware-accelerated mode (i.e. the GPU) if you select 'Set PhysX Configuration' in your nVidia control panel.

If you have ATi hardware, you can only use the software mode - Unless, of course, you have the Aegia PhysX card.

It depends on the game -- like Sacred 2 will ask you if you want to use the PhysX mode or not, and tells you that if you use the Phys-X mode, it may slow down the 3D graphics -- and it does -- very noticeably. The phys-x graphics look really n ice, but they made that game very slow, so I'm glade it had a toggle.

So turning the phys-X on or off is something that was present IN the GAME -- not just on the Nvidia panel.

You say it's is just as much a part of the game as is the lighting -- but you can turn various parts of the lighting on or off in the game -- so you disprove your point -- i.e. just as you can turn off Screenspace anti-aliasing, or high-quality geometry or shadows, you would have an option to turn off physX usage if physX usage was a part of the game.

I don't think physX usage is used in this game -- because there is no toggle for it. All games that have used phys-X processing have had a toggle for it because it creates a big impact on 3D processing when it's on. So it depends on what card you have and what other graphics features you have, as to whether or not you want it turned on.

No, I'm not "disproven". You can adjust the lighting as you can adjust the PhysX settings. PhysX has two modes; Software and Hardware-Accelerated. If you turn PhysX off in-game or via the control panel it reverts to software mode, i.e. it is processed on the CPU. If you leave it on, it's processed on your GPU or dedicated card (i.e. it's accelerated by the hardware). PhysX is vital to the game as it's about the physics programming (It's not about graphics as you say, it's nothing to do with that beyond being able to be processed on nVidia GPUs and appearing as better visual physics (Such as explosions)), and without that then the game just wouldn't work.

The control panel is a global setting, but you can disable it in the menus for certain games, with Sacred 2 being an example. If you change the control panel to "CPU" then it would always process on the CPU. If you put it on "auto-select" then it would use your in-game settings; Off would be CPU, On would be GPU.

Assumption time: It also depends what the developer has done with it. I assume there's two versions a developer can use, i.e. one version would just be software for all, and the other would be a toggle between software and hardware.

The game uses PhysX engine, thats' correct. But it does not use GPU acceleration at all.