Primer: While I have the advantage to have worked already with, for, and sometimes against patent lawyers, I am none myself, so take my words 'with a grain of salt', and ask your patent lawyer, if in doubt. I won't give legal advice here, but mostly tell from experience, and my personal opinions and conclusions. I try to avoid errors or misconceptions, nevertheless.
If you create a piece of artwork, and if you document and publish it, this piece and all its physical and nonphysical representations (e.g. print and web publication of depictions and/or descriptions made by you or proxies ordered by you to do so) are your very own property. And all these are protected by law, and get automatically 'Copyright' protection, even without having filed such. In some jurisdictions it is possible to file a copyright on top of the 'natural' copyright. This is usually done for print publications, and has the only purpose to have officially documented your claim(s), to be able to defend a copyright easier in court, once there is trouble. And it's often done, if there are performing agents or contractors employed to do the actual work, to 'fix' the claims.
In result, the legal owner of a copyright claim has the FULL rights to decide, how the claimed item is dealt with, whether reproduction is allowed, to give full or purpose-limited re-publication licenses to others, to decide for license fees, or also to deny reproduction at all.
Side note: It is NOT necessary to mark an item or representation with the (c) or © sign to be protected - unless one files a copyright. In latter case marking is mandatory, as the sign basically marks the copyright having been filed. I suggest to omit the use of such a sign for unfiled, natural copyrights.
But this copyright protection applies ONLY to SINGLE ITEMS and their representations, and does explicitly NOT extend to principles to create such pieces, or whole classes of similar design derivatives. To give this extension, one needs to use other protection schemes, called Patents.
In most jurisdictions there are two classes of patents, sometimes not even containing the word 'Patent' or its translation into the respective jurisdiction's language. Usually there are 'full' patents, and there are 'Design patents'. And patents of both classes need to be filed, mandatory. I won't elaborate the differences between these two classes here in detail, unless asked for; I just note the fact.
A patent's purpose is to protect ideas, or methods for producing items or whole classes of items from reproduction by others, with economic impact on the original claim holder's intellectual property - similar to the protection given by copyrights for singular pieces of artwork. This can be the detailed construction of a machine, but also a particular detail applicable for many purposes. And it can be the application of some method for a particular class of applications. It gives its holder an exclusive right to use the method or particular design, or give licenses to use it to others - for a limited time. And patents are expensive - to get them, and finally also to hold them, as there's a (growing) yearly fee to be paid to continue holding them. Once a patent expires, its knowledge becomes basically 'public domain' (and can not more be re-patented by someone else). And: Patents can be sold or otherwise given to others, transferring all rights, including right to give licenses or further transfer of rights.
Patented items have to be marked MANDATORY with a note about having been patented, patent registration number and information about the particular registration patent roll included, to tell a potential copier that it's forbidden to copy even the idea without getting an explicit license from the rights owner; documentation and depictions of items have to be marked accordingly, to avoid any doubts about the fact.
Note, that patents are basically valid only in the respective jurisdiction, where they were granted. There ARE some bi- or multilateral treaties around, that extend locally given patents automatically into other jurisdictions, but that is not always given. This is a touchy subject, and I won't tell too much about - once one has to deal with international patent laws, a professional (patent lawyer) is asked for. Who does not know, what happens, if some 'chinese knockoffs' of items patented in your country are imported?
These are also a bit dangerous, as the legal owners of these have the right to follow a wide range of policies, how to deal with. Some (like some well-known movie studios) are very rigorous and sue anybody, fans included, who uses one of their marks, logos, or other intellectual property. Others (many sports clubs among them) even encourage, or at least tolerate use of their signs, up to the point that fans can show their tattoos on a club's web presentation. As long as there is no competition with such a club's own merchandising efforts, there's usually no issue. But please be cautious, and maybe google for experiences of others with that particular rights holder's policies - or best directly ask there, to get a clearly expressed 'yay' or 'nay'. In latter case simply abstain from use of such marks.
And note that these trademarks don't need to be filed, while they often are - once filed, they're nearly carved in stone. But already a continuous use, for a longer time, suffices to give an effective protection, and creation of rights associated with - this is somewhat similar to the 'natural' copyrights.
Well, all our PIECES and documentation associated with are copyrighted, automatically, without need to file for protection of our intellectual property. But once we want to get protection for methods and principles, or particular classes of applications, we need to file patents or design patents. Now I'll give you examples.
I know that there are widespread misconceptions, how far a copyright protection extends. And I saw already often vastly exaggerated claims, like ownership of a weave, and thinking to have the ability to hinder others from reproducing it. This is simply invalid - who manages to redo a weave from a photo, has done the work, and is allowed to do so. Crediting the original publisher is just good behavior, to have these publishers continuing to publish their sometimes awesome stuff. What IS protected, and covered by a simple copyright (filed or not) is the possibility to disallow reproduction of a particular, unique design, made from. But drawing the line between 'inspired design' (allowed) and 'shameless copy' (usually NOT allowed without permission) is difficult.
ALWAYS differentiate between piece/design and technique to determine, whether copying is appropriate, or not.
Many people think, that it's allowed to copy other people's copyrighted artwork (or even patented ideas) for their own, private use, or even for sales purpose. This is only partially right. The main key word for a decision whether something is allowed or not, is 'commercial impact'. So if you make a personal copy, that isn't given away, or only a single one as gift to a friend, there is no (or no noticeable) impact on the original creator's commercial interests, and so usually allowed. But once you sell items, or even give items for free, be always aware, that such an impact could arise. Once it does (and even a potential impact does already!), get permission or license to do so; if the rights holder asks for a fee, pay it, as (s)he is entitled to - or waive the reproduction and make something else.
I hope, some of the readers found this valuable.
Have fun :)
-ZiLi-
P.S.: If a patent lawyer happens to read this, and sees something that is outright wrong, or ignoring significant facts: May I ask you to tell me about such errors or omissions, so I can correct the mistake or fill the gap?