Converting MERP adventure modules for use with BRP

[Redge]

Hi All.

I'm currently running a MERP ready to run adventure (The Trolls of Misty Mountains) using the BRP rules and thought I'd share my thoughts on this to see if anyone else out there has tried this.

Skills: As MERP is a D100 system the skills values need no conversion.

Stats: Guidelines for 3D6 character stat conversion are provided in the front of all ICE's MERP (and Rolemaster) modules so converting the NPCs was easy enough although did take some effort.

Monsters: For monsters I've used the stats from the BRP gold book rather than try to convert them. This could unbalance the game I guess if say a BRP troll were significantly different in potency from a MERP one.

So far the game is playing very well indeed and I have to say that these old MERP modules are very detailed and of a high quality.

One thing that I haven't found an easy conversion rule for is the MERP difficulty modifiers for things like opening doors, spotting and disarming traps. etc. MERP will say a door is Hard (-10) to open whereas BRP would say the door was stuck and needs strength 20 to open which would be resolved on the resistance table. Any ideas anyone?

[Mechashef]

I can't see any problem with things like spotting and disarming traps. Can't you just use the appropriate skills from BRP and use any appropriate modifers as specified in the scenario?

Regarding opening doors, I don't know.

I played MERP a very little bit around 20 years ago and have a copy of the rule book, but can't find anything about opening stuck doors. It does have a resistance table but no mention I could quickly find about using it for such things.

[Mechashef]

I had another look through the MERP manual and really can't find anything about doors. Even the troll scenario at the bak of the book is very vague (i.e rooms are blocked by boulders that need 1 or 2 strong characters to move).

I suspect that my edition of MERP doesn't have anything about it.

[Foen]

Typically in RM-based games the description of a task has both a difficulty (such as Hard) and a modifier (in this case -10), and would be resolved by using the Static or Moving Maneuvers table. Theses tables have a d100 (potentially open ended) roll to resolve them and a column for each difficulty level. That means the modifier (-10) isn't sufficient in isolation.

For MERP, however, I think the difficulty level just translates to another modifier and the static maneuvers table (used for picking locks, but not jumping pits) only has one column. That makes static tasks a bit easier to convert.

Stuart

[Redge]

I can't see any problem with things like spotting and disarming traps. Can't you just use the appropriate skills from BRP and use any appropriate modifers as specified in the scenario?

Regarding opening doors, I don't know.

I played MERP a very little bit around 20 years ago and have a copy of the rule book, but can't find anything about opening stuck doors. It does have a resistance table but no mention I could quickly find about using it for such things.

Hi Mechashef, I'm fine with which skills to use my point was how to convert the MERP/RM difficulty levels to BRP. There is no 'open stuck door' in either system so this becomes a strength test. In BRP we could use the STR x 5 characteristic and apply the -10 (Hard) from the MERP module as a penalty.

[Mugen]

Skills: As MERP is a D100 system the skills values need no conversion.

I'm not sure about this.

My memories may not be accurate, but as far as I remember, MERP tables work more or less like this :

0 or less : fumble

1 to 75 : failure

76 to 90 : Half success

91 to 110 : Success

125 to 150 : Good success

151 to 175 : Very Good success

176+ : Critical success

Which means one with a bonus of +35 facing a medium difficulty have a 45% chance to have a success, not counting the Half-success.

So, a +35 would translate into a 45% skill.

One thing that I haven't found an easy conversion rule for is the MERP difficulty modifiers for things like opening doors, spotting and disarming traps. etc. MERP will say a door is Hard (-10) to open whereas BRP would say the door was stuck and needs strength 20 to open which would be resolved on the resistance table. Any ideas anyone?

In fact, a roll on the resistance table is a characteristicx5 roll with a difficulty equal to (opposing factor-10)x5%.

[Agentorange]

The other way to look at it might be not to try a direct translation. Some things simply won't map across. Go with the situation. Is there any information about why the door is hard to open. Is it big and heavy ? - then it's a STR test. A cunning lock ? - then it's skills test. Use the context rather than the mechanics if you see what I mean.

[Foen]

Just for clarity (as I think I failed my Speak Clearly skill last time), MERP has both a difficulty and a modifier. From the rulebook (1993 second edition, table MT-2), the difficulties for Static Maneuvers are:

Routine +30

Easy +20

Light +10

Medium 0

Hard -10

Very Hard -20

Extremely Hard -30

Sheer Folly -50

Absurd -70

So a Hard (-5) Static Maneuver has a -15 adjustment (-10 for Hard, -5 for the modifier) to the skill roll. Hard (-10) is actually the same as an unmodified Very Hard roll. I guess they don't just say Very Hard because the underlying Rolemaster system uses separate tables for each difficulty level, and MERP adventures are also written for use with RM. For Moving Maneuvers, the multi-column approach is retained in MERP.

All that said, I'd agree with Agentorange and apply situational common sense instead of looking fo a direct conversion, but that is just my 2c.

Stuart

Edited October 26, 2010 by Foen
To be even more clear!

[Redge]

Hmm, I've read a lot of MERP modules and I'm not sure I've ever seen anything like Hard (-5) I thought that the number in brackets was just a reminder of what the penalty was at that level of difficulty.

As you say Agentorange's advice is sound and that's what I've ended up doing. I ended up using a strength test and judged hard would be around 15 or 16. So a single character may struggle with it for a couple of rounds but two or three people combining their strength should be able to shift it.

Whilst writing this it occurred to me that the average of STR and SIZ would be a better option (i.e. (STR+SIZ)/2).

When it comes to tests that map to a skill I've been using the MERP modifier as a straight penalty to the skill check. For example a Very Hard to pick lock gives a -20 to the roll.

[Foen]

You're right - it has been a long time (over two decades) since I last played MERP/RM and I got confused when re-reading the rulebook. I take it all back!

Stuart

[Redge]

No worries Foen, if you're like me you probably have the rule systems for 50+ RPG an table top games floating around in your head!

Thanks for everyones help on this thread.

My players are now well into the second adventure in The Trolls of Misty Mountains module and it's going great with the BRP rules with minimal work from myself except for reading the module before hand and converting the major NCPs. We rolled the players (2 of them) up at Heroic level and they're dealing the troll and orc infested mines despite been out numbered. I'd say that the BRP orcs aren't as tough going as the MERP ones though.

[Guest Vile Traveller]

I like to use Dark Trolls for Uruk-hai.