In discussing Unity tags recently, I noticed that we don't yet have a tag for physically based rendering.

This is getting to be a popular feature in games/engines, showing up in Q&A here (34 posts so far containing "physically based rendering" and 43 containing "BRDF")

The techniques and terminology differ substantially from conventional lighting models used in games. I think this is a good candidate for a tag, as a topic in which one could be a subject matter expert.

The trouble is physically-based-rendering is one letter over our tag length limit.

So, I'm debating between a few options:

  • pbr is short & easy to type, but not as clear unless you're already well-versed in the topic's parlance. It's also not search-friendly: if someone starts typing "physically..." the tag search won't suggest pbr (like how typing "ambient..." won't suggest )

  • physically-based-render keeps the core meaning, but is a little awkward, since we never talk about a "render" being physically based, just rendering, lighting, shading, or materials. Maybe "renderer" since this can affect renderer-level details like what to include in a G-buffer?

  • physically-based is likely to get polluted with people using it to ask about physics-based gameplay mechanics, rather than rendering.

Since this is my first tag addition, I wanted to ask for META's expertise so I can get it right the first time, and avoid making work for someone else to fix my tags later.

  • \$\begingroup\$ It seems the greater popularity lies with "BRDF". Of the posts showing under a search for "physically based rendering", we only have 12 actual questions. Of the posts showing under the search for "brdf", we have a total of 21 questions. 4 questions appear under both searches. \$\endgroup\$
    – Gnemlock
    Commented Sep 18, 2016 at 4:29
  • \$\begingroup\$ I'm not particularly for it, but I found another variant through google. One particular paper refers to "pbf" as "model based rendering". \$\endgroup\$
    – Gnemlock
    Commented Sep 18, 2016 at 7:41

2 Answers 2



Main Tag:
Synonym Tags: ,

I suggest the tag . It is easy to implement, stays true to the most used and accepted term, and still easily solves other possible issues:

  • There is the issue where users unfamiliar with the term physically based rendering would not understand the term. That said, if users are completely unfamiliar with the term, we probably should not expect them to be using any variation. On the flip side, as we see questions that fit this tag, we should be adding the tag. As users notice the new tag, those that are unfamiliar with the acronym "pbr" would hopefully look to the user guidance, and familiarise themselves with its use.
  • pbr is not search friendly, but than, main tags do not need to be. If we implement alternate synonyms, the alternate tags will still come up when a user searches. We can thus implement one or two alternate tags (I suggest and ) to further facilitate potential user searches.

Regarding universally accepted terminology, as says Google

Running a quick google search for physically based rendering, I find that "pbr" is a common acronym. It appears in the blurb of the top hits, along side "physically based rendering". Both "physical based rendering" and "physically based render" are automatically corrected to "physically based rendering", thus returning the same hits.

Regarding setting up synonyms

I suspect we would need a moderator to set the synonyms; from a rough inspection, we would not have enough users with permission to vote on tag synonyms, should all the suggested questions receive the new tag. That said, I don't think that will be too much of an issue.

  • \$\begingroup\$ What about physics-based-rendering? Does that come across as less awkward than the adjective-used-as-adverb option? \$\endgroup\$
    – DMGregory Mod
    Commented Sep 18, 2016 at 4:46
  • \$\begingroup\$ That said, it occurs to me that users not already familiar with the term "physically based rendering" may not even consider adding such a tag. If we want to stay true to the term, I would suggest having pbr as the main tag. As more knowledgeable users add it to relevant questions, users are sure to inspect the usage guidance for why it was added, and in turn it would in theory catch on. \$\endgroup\$
    – Gnemlock
    Commented Sep 18, 2016 at 6:05
  • \$\begingroup\$ @DMGregory, I had accidentally delete my earlier comment, but I think physics-based-rendering might be to confusing. It wouldn't attract as much incorrect tagging as physically-based, but I think the same problem might attract non-attention, if that makes sense \$\endgroup\$
    – Gnemlock
    Commented Sep 18, 2016 at 10:08

I think physically-based-render would be the best compromise.

The tag wiki should start with something like "Physically based rendering is ...".


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