To obtain a design right, an application is required in which an image of the design must be deposited. However, no assessment is made as to whether the application is justified the judge may decide if the design owner sues someone. However, there is also a design right if the design is not deposited. However, the protection for this is limited to borrowing or copying. The coincidental similarity of two products is therefore not an infringement of the unregistered design right, but rather a registered design right. Using aluminum oxide is essential in the process.
If a design is protected, others are not allowed to use it in their products. The marketing of products that deviate on minor points but do not create another general impression are also covered by the protection and are therefore prohibited. It is explicitly permitted to make a replacement part or to repair the protected product with the intention of returning it to its original appearance. This is included in the law to prevent the market for spare parts from being blocked with a design right.
A consumer who wants to print and use protected models for his own use does not have to worry much about design rights. A company that prints models to order will have to be more careful. It may be able to invoke that repair clause when it comes to replacement parts. But whether this clause also applies to only alternative parts a new case, a different color for the cover, your fear will only be decided after a whole series of lawsuits.
Trademark law protects the use of a distinguishing sign against abuse by others. A distinguishing sign is, for example, the name or logo of a product or service, but also forms of products can be protected as a brand. The best-known example of a shape brand is the Coca-Cola bottle. Other shape brands are the Yakult bottle or the triangular chocolate.
A shape can be a brand when it distinguishes the product from competitor products. That works fine with that Coca-Cola bottle. However, the LEGO block turned out not to be a brand. That block simply has to have that shape to be able to build with it, and then that shape cannot be monopolized as a brand. It must also be a form that is purely for decoration. Forms that realize functionality must be protected through a patent.
Three-dimensional printing can run into trademark rights in two ways. First of all, people can print forms that are protected as a brand. But people can also print all kinds of products and provide them with the brand name or logo. That is trademark infringement: the trademark holder can claim the products and have them destroyed. Even if you only wear or use them in public. And note: not only if the product is a counterfeit of the real brand product. Even if it is a completely self-made product, for example a chess set.
In the case of trademark law, just as in the case of patent and design law, the restriction applies that a trademark can only be infringed on commercial use. Non-commercial counterfeiting or use of a trademark should therefore not be an infringement. However, anyone who prints and sells or markets branded products, also on a limited scale, commits infringement.