Converting DH powers

By Darkmoon_Knightess, in Black Crusade

So, call me stupid or somesuch, but I am not really getting converting things like pyromancy and biomancy after doing all of the math and figuring out thresholds and such. Are they really intending the focus power tests to be so horrid? Because Force Bolt by their example would be a -10 rather than the +10 in the book.

Could someone provide a way they've done it that is balanced? Or perhaps clarify this for me? i just really am not getting it.

Conversions are really going to be more art than science. There is no direct, 1 for 1 correlation.

Unfortunately the wording in the little 'converting Dark Heresy powers to Black Crusade' is a little vague here (and so is the source of my problem!) It mentions something for every five points of threshold in the Dark Heresy book, it is to be treated as if the spell was one step more difficult in Black Crusade, therefore Force Bolt threshold of 13 translates to a -20 penalty on my WP test to cast it in BC. This makes the psyker casting Force (Psychic? Don't have my book on me atm) Blade take a -40 penalty to their focus test because of it's 20-something threshold in DH.

Now, I know this can't be right, but the way I am reading the 'converting powers' snippit I seem to be following the process to the letter.

Dagny said:

Unfortunately the wording in the little 'converting Dark Heresy powers to Black Crusade' is a little vague here (and so is the source of my problem!) It mentions something for every five points of threshold in the Dark Heresy book, it is to be treated as if the spell was one step more difficult in Black Crusade, therefore Force Bolt threshold of 13 translates to a -20 penalty on my WP test to cast it in BC. This makes the psyker casting Force (Psychic? Don't have my book on me atm) Blade take a -40 penalty to their focus test because of it's 20-something threshold in DH.

Now, I know this can't be right, but the way I am reading the 'converting powers' snippit I seem to be following the process to the letter.

No, that regards effects that increase a psychic power's Threshold, rather than determining the base threshold.

However, if you still want to use that as a rule of thumb, I suggest you assume a starting Difficulty of Easy (+30), rather than Challenging (+0) - that brings Force Bolt to a +10, and Psychic Blade to a -10, rather than -20 and -40.

N0-1_H3r3 said:

However, if you still want to use that as a rule of thumb, I suggest you assume a starting Difficulty of Easy (+30), rather than Challenging (+0) - that brings Force Bolt to a +10, and Psychic Blade to a -10, rather than -20 and -40.

But doesn't Psy rating affect the difficulty?

It does, by 5xPR. That's assuming BC uses the same psychic powers rules that DH uses. I don't have my book yet, so I don't know.

I wouldn't change difficulty of powers if you are translating them to a WP based roll. I would either create XP costs for each power like DW powers, or I would edit the strength of the powers. But really, just converting them straight to WP tests should be enough. You will need to change overbleed rules to DoS rules though.

DJSunhammer said:

It does, by 5xPR. That's assuming BC uses the same psychic powers rules that DH uses.

I'm assuming you meant DW, not DH, but yes, the system is basically the same. There are a number of differences, though.

DJSunhammer said:

I wouldn't change difficulty of powers if you are translating them to a WP based roll. I would either create XP costs for each power like DW powers, or I would edit the strength of the powers. But really, just converting them straight to WP tests should be enough.

Not for Black Crusade. The Black Crusade psychic rules have different powers with different Difficulties for each power's Focus Power Test - some are easier to use than others. The OP seems to be trying to reflect that in his attempts to convert the other DH disciplines.

DJSunhammer said:

You will need to change overbleed rules to DoS rules though.

Personally, I'd avoid that - scaling by Psy Rating should be sufficient; if you try and scale by both Psy Rating and Degrees of Success, then you get powers that improve exponentially, rather than linearly. When designing a new power (as opposed to converting one), if you're going to employ both Degrees of Success and Psy Rating to scale a power's effects, have them do specifically different things.

Then again, personally I'd avoid trying to convert the powers across using only those guidelines... I'm much more inclined to rebuild powers from scratch rather than try conversions.