Over the past 1.5 years I've basically read every single raytracing paper published in the past 10 years, and have been slowly working to implement relevant papers into this renderer. Recently I found out that one of those papers was patented, and there's no way to use the ideas inside it[1]. This by itself is not a huge issue as I can avoid using the technique and I don't think it will have a massive impact on performance. The bigger issue is that I don't know what other algorithms are patented that I have no idea about. Maybe some of those algorithms are just straight necessary in order to hit any reasonable performance guideline. In that case, this whole project is fucked and I should go do something else.
I feel seriously disheartened about the whole thing now. I do not currently have any income, and I do not have enough money to fight off a lawsuit. Even hiring a lawyer to search for potential patent-infringement seems extremely expensive. I don't know if I should give up on this entirely and move to using a commercial game engine, keep working on this and ignore the existence of patents (except the one I found), keep working on this and search out for more patents to make sure I'm not infringing anything, or do something radically different altogether.
[1] The patent # is 10580193, but I would not recommend looking it up if you are in graphics work due to how willful infringement works.
The other important thing is to have appropriate incorporation and liability insurance once you are actually exposing yourself as an entity.
Many patent owners would be glad to find a new licensee at a fair price. Since you intend to commercialize your project, you will be able to pay reasonable license fees as you make sales.
The large majority of patent owners are in it to make money. They will sue a billion dollar company to get a large settlement a they will try to get a small settlement out of a small company. Basically no matter what size you are, they will try to make it affordable for that company, but it is a negotiation.
Now I am not a lawyer, but I've been through this and have been a party to those negotiations. You'll be fine.
Also anyone in software is likely violated a whole raft of patents that you don't know about. The field is littered with overboard patents that you would not even think apply to you. We will likely be fine since most of those patents are not being enforced and also we will likely be fine if they are enforced because they will go after the big firms before they come after us.
Negative thoughts do bring bad luck after all :)