Buyer:
Editorial - Can use for newspaper, magazine article, blog/website for describing ideas, non-commercial use like presentation, personal use.
Royalty Free - Can use commercially for any purpose. Note, there can be additional licence restrictions.
Seller:
Editorial - Anything with a brand/logo/mark etc must be sold/3D modeled as editorial. Only restrictions are some brands still do not allow this (BMW, Lamborghini, etc). It can be difficult to find out which brands have restrictions as you need to check each company individually. You can have your item requested to be taken down with a DMCA notice.
Royalty Free - Can sell commercially for any purpose without legal implications or take down requests unless you have obviously infringed copyright. You can also place additional license terms for the buyer such as they cannot print your model, re-use the concept, use only in particular situations etc.
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Think of it this way, SMEG feature in a lot of architecture, so does popular book/soap/furniture brands. They usually dont have a problem with this because as Tom mentioned its probably not being used in a defamatory way and actually promotes their business for free. Doesnt mean its entirely legal but it fits nicely in the grey area.
In regards to your situation if its entirely for building a portfolio 99% of the time you wont run into an issue. Again, grey area but in the 12 years I have been in this industry not once have I seen or heard of anyone get in legal trouble over using an IKEA sofa in their render.
edit:
As a side note if you are a freelance artist its also a smart choice to put into your contract that the client is responsible for any and all claims, costs, expenses including attorney's fees for any copyright infringement within the received images (this includes and is not limited to copyright, patents, trademarks, industrial designs and geographical indications).