yeah sure I dont think making your own personal merch is illegal. It might be if you were to wholesale them. I think
Umm, you have better check that from devs, after all logos, names etc. have usually trademark and you can't use such to sell something when you are not holder of copyright or trademark. @Nadeox1 might know for sure, but certainly don't go selling stuff with BeamNG logos without consulting the devs.
Yeah i wasnt going to sell anything i mean im just asking if we can use it to make merch for ourselves not to sell.
In that case it is good to check terms of service you want to use, some did have small print that reserved them rights to use images etc. send to them, which might be problem with BeamNG copyright again. Sometimes simple things are rather complicated.
Technically BeamNG and logos are copyrighted/trademarked material. Non-technically, if it's for personal use..
The issue you run into with this kind of thing is that it is in the trademark owners' own interest to protect their name. If you started making say shirts with the BeamNG logo, people bought them and found they were of horrible quality... well that would look bad for the brand (and you could probably be sued for the resulting damages too). Another aspect is that you may be seen as trying to profit off the reputation of someone else's work (and morally speaking, this is pretty universally considered a scummy thing to do). Some companies are more strict with this than others.