d20 Monsters to OD&D/BD&D

[jdrakeh]

This began as a Fight On! article submission, though due to some personal issues (including a recent job layoff) I'm not going to be able to finish it. . . so I'm posting the raw maths here. When dividing, round results up to the nearest whole number:

d20 HP to O/BD&D Health Dice

d20 HP / 6 ≈ OD&D Hit Dice
d20 HP / 8 ≈ HD&D hit Dice

d20 AC to O/BD&D Armor

19 - d20 AC ≡ OD&D Armor
19 - d20 AC ≡ BD&D Armor

d20 BAB to O/BD&D Weapon Damage Bonus

d20 BAB / 2 ≡ OD&D Weapon Damage Bonus
d20 BAB / 2 ≡ BD&D Weapon Damage Bonus

d20 Speed to O/BD&D Movement

d20 Speed in 1" Squares x 2 ≈ OD&D Movement in Inches
d20 Speed in Feet x 4 ≈ BD&D Movement in Feet

Special Attacks / Defenses

Unfortunately, in D&D, these abilities always have been (and probably always will be) exception-based. Pick and choose special attacks, defenses, and non-combat abilities from the d20 list as you (the DM) deem interesting.

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You will note many approximations above. This is necessary given that raw values for certain things have changed wildly between editions of the game (movment rates for certain creatures being a key example). In calculating approximate values, I errored on the side of the two systems beng converted to. Still, anomalies exist (e.g., dwarves are bit more mobile than normal).

 

[Ant]

Thanks for this, jdrakeh. I was really looking forward to seeing this in Fight On! -- I'm sorry that it won't make it in.

 

[jdrakeh]

Thanks for this, jdrakeh. I was really looking forward to seeing this in Fight On! -- I'm sorry that it won't make it in.

Thanks for the vote of confidence.

I simply have a lot on my plate right now. If I have the time after finding steady employment again, I've been thinking about releasing my own 2-page fanzine in the mold of Iridia (an 8.5" x 11", double-sided, flier) where the conversion article, some alternate rules for "stunts", and a basic skill system that I've been using will likely appear in addition to the setting that I am currently building on weekends (and like Iridia, you'll be able to download the 'zine for free).

Nothing against Fight On, it's just that I can work on my own 'zine as time permits and don't have to worry about deadlines and such (which fits into the chaos that I call my life much better, currently). Plus I have stupid amounts of layout software, clip art, and commercial font packs that I paid for last year in anticipation of releasing EZ20. I mean tons of that crap (and stuff like Adobe apps aren't cheap). I figure that I had better get some use out of it

 

[w_earle_wheeler]

After reading about Fight On! on the OD&D boards, I began a futile quest to track down a mimeograph machine in the area for my own OD&D style zine -- sadly, even the "Classic Style Printing" place didn't have one!

 

[jdrakeh]

After reading about Fight On! on the OD&D boards, I began a futile quest to track down a mimeograph machine in the area for my own OD&D style zine -- sadly, even the "Classic Style Printing" place didn't have one!

Yeah, I'm just going with a PDF for primary distribution (I have access to fonts and image software that can recreate the mimeograph look, though). That way, consumers can print it how/when they like (or if they want the full snail mail experience, they can have me print it and mail it to them for a nominal fee).

 

[Flynn]

Would the following be of any assistance in pursuing this path?
http://basicfantasy.org/download.cgi/BF-Monster-Conversion-Supplement-2006.2.pdf

It's for Basic Fantasy, which I believe is a retro-clone of OD&D/BD&D with some D20-isms thrown in. It would probably not be hard to look at this document and make some further adjustments, if you thought they were merited.

With Regards,
Flynn

 

[jdrakeh]

Would the following be of any assistance in pursuing this path?
http://basicfantasy.org/download.cgi/BF-Monster-Conversion-Supplement-2006.2.pdf

I play BFRPG so I'm aware of this document but it won't help much here. For starters, it deals in a lot of approximations, as well. The big issue, though, is that some creature stats (dwarf movement, for example) have a much different mathematical representation in D&D 3x than they did in earlier editions, while the same elements of other creatures (elf movement, for example) don't.

This makes the application of a single forumula for converting the elements in question impossible. While I could undoubtedly present several dozen special case formulas to deal with such things, the introduction of such maths would make conversion a much more time consuming process while providing little in the way of recognizeable benefit during play.

As one of the largest appeals of BD&D is its simplicity, as well as its ambiguous mechanical representation of most game elements, I think that the amount of time and trouble that exact conversions introduce misses the point. The maths that I present here are fast and simple, having been applied on the fly during actual play.

They are not 100% accurate though, in the end, the trade off was one of utility versus accuracy. I decided that sacrificing a point or two of accuracy when converting movement rates or a +1 bonus to HP here or there was worth the greatly increased utility i gained by dropping special case conversion formulae (and so far, players have never noticed the missing points).

[Edit: If not immediately clear, the armor and attack bonus calculations above are exact, while the Hit Dice and Movement rates are approximations.]