Recently I was working on a homebrew subclass that had an ability that scaled a die with level (d6 at 3rd, d8 at 10, and d10 at 18th). I've seen a lot of times in the snippet part of the character sheet this show up in bold (such as the way the bardic inspiration die is displayed as 1d8 or otherwise in the character sheet screen). How would I format this in writing my own homebrew?

You're looking for snippet codes (usable only in the snippet boxes); in your case most likely what you want is to add level scaling to the feature with the correct dice set, then you can simply put {{scalevalue}} in your snippet and it should swap in the correct dice on the character sheet.

Unfortunately this isn't a code you can test using a custom action (due to the level scaling) so keep in mind that if you add a sub-class to a character sheet, it can take a while before changes you make appear on the sheet (up to 20 minutes); sometimes you can speed this up if you lower the character's level until the feature disappears, then level them back up again.

Other snippets can usually be tested on the character sheet using a custom action, rather than having to add the sub-class.

It might be possible to do this in a custom action if you can make the calculation work right. Basically you need a calculation that results in a 0 for class levels 3-9, a 1 for class levels 10-17 and a 2 for class levels 18 and up. Multiply that result by 2 giving you 0, 2, and 4. Then add 6 giving you 6, 8, and 10. Then its just "<strong>1d</strong>{{some calculation}}"

I'm at work this morning so I can't put any time into this right now, but you might check out this comment on some of the logic I used on a similar thing yesterday. Your request might be a little more involved as the rules written for the one I wrote last night were fairly easily divisible by 6 (changes made at levels 6, 12, and 18). Someone better at algebra than me could probably come up with the necessary formula for you to use.

Edit: Changed my references to class levels, not character levels. Haravikk is correct that you cannot test or use {{classlevel}} in a custom action. For help on using {{scalevalue}} and Level Scaling in your subclass, try this thread.

That depends on how you do it, and what it’s for. For a subclass I would go with Haravikk’s suggestion of using {{scalevalue}} and utilizing the Level Scaling subform attached to the class feature. For anything else you would have to use <strong>1d</strong>{{???}} and enter the correct calculation in where the question marks are as Mairondil suggested.

Quote from IamSposta >>

That depends on how you do it, and what it’s for. For a subclass I would go with Haravikk’s suggestion of using {{scalevalue}} and utilizing the Level Scaling subform attached to the class feature. For anything else you would have to use <strong>1d</strong>{{???}} and enter the correct calculation in where the question marks are as Mairondil suggested.

It would be an interesting calculation if this was characterlevel, not classlevel. I was just thinking of dividing the level by 19, but the @round function is either up or down, not just rounding in general. 

Edit: well that method wouldn't even work either as 18/19 is less than 1. Ugh. This question is going to bug me all day at work.

Ask naruhoodie, she’s the best I know when it comes to snippets.