I just stumbled on this http://www.google.com/patents/US20110012901

does this mean that you are unable to use LPVs in your game without Crytek's permission?

That is ugly... Yes, it means that if you use the LPV technique published in their paper, then they can sue you in the US for patent violation and demand you pay them compensation.

Having a look around google patents, it seems they actually have a lot of patents...

However, many companies register patents for defensive purposes only -- to ensure that "patent trolls" don't claim their own ideas and then sue them. To be safe, you'd have to get in contact with them and obtain written permission to use their idea.

Personally, I try to just pretty much ignore software patents. A lawyer would advise against this approach, of course, but I'd rather simply take the risk, and bet that Crytek would not sue a small indie like myself and risk all the bad publicity that it would bring on themselves from being so evil...

*cough* Bethesda *cough*

If you read a paper from a company, you can be pretty sure they don't release it to share their ideas,

they do it because they need to publicate any technique they want a patent for, isn't it?

Anyone knows how those 'licensing fees' look like in practice?

Personally, I try to just pretty much ignore software patents. A lawyer would advise against this approach, of course, but I'd rather simply take the risk, and bet that Crytek would not sue a small indie like myself and risk all the bad publicity that it would bring on themselves from being so evil.

I've actually had multiple lawyers tell me to just ignore software patents. Don't look at them, don't read them.

If you know something is patented, then don't do it.

But if you have no knowledge of the patent, ignorance can actually be a good defense for companies. First it is unlikely to be discovered. Next, because you haven't read it exactly it is that much less likely that you followed all the steps of the patent, making it less likely that you actually infringed and instead came up with a similar-yet-different technique. If the company wants to fight it, an accidental infringement can be useful as evidence that the technique is obvious and not novel. And finally, if you know about the patent it becomes willful infringement, which has a much greater penalty than an accidental infringement.

Software patents are a very strange area of law.

Sometimes ignorance really is the best policy. Don't break it if you know it, but at the same time it is generally a bad practice for programmers to read every new software patent.

I've had lawyers give exactly the same advice as frob. Take the "Sgt Schultz" approach to patents. (ask your parents, or Google it :))

You can have "willful" patent infringement or "not willful" infringement

If you unwillingly infringe on a patent (i.e. you just did your thing and it turns out you happened to infringe), of course the patent holder can be entitled to reasonable compensation.

However if you willingly infringe (you made your thing, knowing full well that what you were doing was patented by someone else), the patent holder can be awarded up to triple damages.

That's why a lot of companies have policies that their engineers not look at patents.

I've actually had multiple lawyers tell me to just ignore software patents. Don't look at them, don't read them.

If you know something is patented, then don't do it.

But if you have no knowledge of the patent, ignorance can actually be a good defense for companies. First it is unlikely to be discovered. Next, because you haven't read it exactly it is that much less likely that you followed all the steps of the patent, making it less likely that you actually infringed and instead came up with a similar-yet-different technique. If the company wants to fight it, an accidental infringement can be useful as evidence that the technique is obvious and not novel. And finally, if you know about the patent it becomes willful infringement, which has a much greater penalty than an accidental infringement.

Emphasis added. This is a really big deal, particularly if you're employed. Do not go digging through patents in your field and reading them. It opens you up to a whole world of painful liability.