2 (vaguely related) topic: Horse and Jumping

[Lloyd Dupont]

I was reviewing Jumping rule.. not that I think it might be important but I was reviewing all skills, be sure I understand them and find them a use, and I wanted to give Bulrathi amazing Jumping ability since they are creature from High G world. Dunno it f it's important... but it's cultural!  
For the record I made Bulrathi lightweight and strong, ie. SIZ 2D6+2, STR 3D6+9

Now jumping in the rule book is a bit lackluster. it's 3m x 1m. which you can double on special. In D&D (sorry about that unholy name 😮 ) it's 1 foot per STR point... mmm... not good either huge creature in BRP have high STR and automatically jump very far! 😮 

I was thinking how about I base it on MOV and tweak it a bit with Skill% and STR/SIZ ratio. A human has 10 MOV. So 10 feet base. And maybe I could add Skill/10% in feet. In case of failure I remove the skill bonus, or double it in case of special, seems nice.
Question 1: I would still like to spice it up with a SIZ/STR ratio bonus still... perhaps simply multiply by STR/SIZ but this might be "too Math intensive" for smooth game play...
Or maybe I simple add a G factor? HighG creature => x2 jumping range (in normal G). and when jumping in HighG divide by 2....

Out of curiosity I looked at horse, how much could they jump with that hey? And then it hit me... Horse MOV is... 12? Seriously? Really?
For the record I found this: https://en.wikipedia.org/wiki/Horse_gait
Mmmm yeah, after all Horse do have a walk speed barely faster than human... ok then...
Question 2: Though, obviously, their top speed is a lot higher (By that I mean a lot more than 20% faster, more like 250% faster - i.e 3.5 times faster), how does that work in BRP?! 😮 
Question 2a. How about jumping? Apparently world record in 2.4 meters up and 8.4 meters long.... mm... doesn't quite scale like human! 🥴

Edited July 2, 2020 by Lloyd Dupont

[Mugen]

What make the subject not easy to handle is the fact SIZ is not linear, and 1 point can either be worth 1 kg or a ton (IIRC). It's not exponential either, which means you can't use subtraction, like in DC Heroes or TORG.

Also, SIZ sometimes also means Height, and longer legs mean longer jumps -considering a species that can jump...

[Lloyd Dupont]

yeah.. I went with my idea of simply doubling the value for HighG creature. Easier to understand and use in game.

Horse still puzzling though.... a MOV of 12 seriously limit it sprint speed... Though it probably  show OK value for daily or walk movement rate...
Maybe quadruped should get a x2 multiplier on sprint values?

[Mugen]

9 minutes ago, Lloyd Dupont said:

yeah.. I went with my idea of simply doubling the value for HighG creature. Easier to understand and use in game.

Horse still puzzling though.... a MOV of 12 seriously limit it sprint speed... Though it probably  show OK value for daily or walk movement rate...
Maybe quadruped should get a x2 multiplier on sprint values?

My skills in biomechanics are not very good, but I'd be tempted to think that creatures in High Gravity environments tend to not be able to jump very well. Think of Elephants, or Rhinoceroses. Evolution granted those creatures very powerful muscles to be able to move their very heavy bodies, but they have very limited ability to jump.

Of course, there are counterexamples, such as whales. But Archimedes helps marine creatures.

Edited July 2, 2020 by Mugen

[Lloyd Dupont]

I see it differently..... Big and heavy creature cant jump much and small and light creature can jump well. Though if they are too small they are also limited to a multiple of body length so it goes down as well...

So, onto Bulrathi, they are no elephant, in fact they are even lighter than human! So they jump better!
Although, everyone (be it elephant, human or ants) has trouble jumping in High G (i.e. all jump length are divided by 2 and fall damage is doubled)

 

mmm... some googling later.... 
it seems that jumping doesn't change much between creature to creature, from 1 meter for giraffes, 2 meters for a flea and human a bit better than the giraffe, but not so much...

As someone on Reddit says it:
The energy to spend is proportional the cube of the length, but so is the muscle power..

 

Edited July 2, 2020 by Lloyd Dupont

[Mugen]

2 hours ago, Lloyd Dupont said:

I see it differently..... Big and heavy creature cant jump much and small and light creature can jump well.

I don't see where this is different fom what I said....

Also, the reason why such huge creatures can't jump well is also because they miss the joints to do so, as their skeleton also changed to better support their body weight.

2 hours ago, Lloyd Dupont said:

As someone on Reddit says it:

The energy to spend is proportional the cube of the length, but so is the muscle power..

The cube, why ?

From a pure dynamics point of view, the distance you'll cover with a jump will depend on the gravitational constant g (dependant on planet), your initial speed V, and the original angle A of your trajectory.

D = V²*sin(2A)/g (*)

Initial Kinetic energy is E = mV²/2. From the previous equation, we can tell V² = gD/sin(2A)

Therefore, Energy required to make the jump is E = mDg/(2*sin(2A))

(*) see  http://mdevmd.accesmad.org/mediatek/mod/page/view.php?id=5251 if you need an explanation.

Edited July 2, 2020 by Mugen

[Lloyd Dupont]

The cube why?
The height you go is roughly the energy provided during your jump divided by your mass and some constant. In fact you said so your self!  

And mass is proportional to volume which is a the cube of a significant length time some constant (approximately) (because we are 3 dimensional beings! ) 
I.e. creature twice as tall are roughly 8 times heavier...

For example
Cats are about 0.5 meters long and weight about 5 kg
Tigers are about 2.5 meters long and about 120 kg, 24 times heavier for 5 time longer (5^3 = 25)

Anyway power generation also increase by the same ratio.. so weight is not that important... mostly geometry...

Edited July 2, 2020 by Lloyd Dupont

[Mugen]

3 minutes ago, Lloyd Dupont said:

The cube why?
The height you go is roughly the energy provided during your jump divided by your mass and some constant. In fact you said so your self!  

And mass is proportional to volume which is a the cube of a significant length time some constant (approximately) (because we are 3 dimensional beings! ) 
I.e. creature twice as tall are roughly 8 times heavier...

For example
Cats are about 0.5 meters long and weight about 5 kg
Tigers are about 2.5 meters long and about 120 kg, 24 times heavier for 5 time longer (5^3 = 25)

Anyway power generation also increase by the same ratio.. so weight is not that important... mostly geometry...

Oh, you meant the creature's length, not the jump's length...

[Lloyd Dupont]

Just now, Mugen said:

Oh, you meant the creature's length, not the jump's length...

Ahem, yes..  reading my post again I can see how one could miss that....

[Lloyd Dupont]

Anyway I don't know where you came with the idea that Bulrathi should be less good at jumping when I explicitly said they were made of lighter stuff and more powerful muscles...

Trying to stretch it perhaps you mean their physiognomy was made for standing and not for jumping perhaps?
Well, be assured, such is not the case!  

Edited July 2, 2020 by Lloyd Dupont

[Atgxtg]

4 hours ago, Lloyd Dupont said:

I was reviewing Jumping rule.. not that I think it might be important but I was reviewing all skills, be sure I understand them and find them a use, and I wanted to give Bulrathi amazing Jumping ability since they are creature from High G world. Dunno it f it's important... but it's cultural!  
For the record I made Bulrathi lightweight and strong, ie. SIZ 2D6+2, STR 3D6+9

Now jumping in the rule book is a bit lackluster. it's 3m x 1m. which you can double on special. In D&D (sorry about that unholy name 😮 ) it's 1 foot per STR point... mmm... not good either huge creature in BRP have high STR and automatically jump very far! 😮 

I was thinking how about I base it on MOV and tweak it a bit with Skill% and STR/SIZ ratio. A human has 10 MOV. So 10 feet base. And maybe I could add Skill/10% in feet. In case of failure I remove the skill bonus, or double it in case of special, seems nice.
Question 1: I would still like to spice it up with a SIZ/STR ratio bonus still... perhaps simply multiply by STR/SIZ but this might be "too Math intensive" for smooth game play...
Or maybe I simple add a G factor? HighG creature => x2 jumping range (in normal G). and when jumping in HighG divide by 2....

 

I'd suggest keeping it simple. Give humans a Base Jump distance in feet, and maybe tweak it up or down a little for STR, SIZ and/or DEX (something like +1m per 4 STR and -1 m per 3 SIZ (see below) might work, but it's probably not worth the trouble).

Standing jumps should cover about half to two-thirds as much as a running jump

For the skill roll, keep it simple: Say a success jumps the typical distance, a failure half that, a special twice that, and a critical three times that. Note that if you use a 10 foot./ (or 3m) distance for a running jumps and 7 foot (2m) for standing jumps, the numbers match up pretty well with real world values. 

4 hours ago, Lloyd Dupont said:

Out of curiosity I looked at horse, how much could they jump with that hey? And then it hit me... Horse MOV is... 12? Seriously? Really?
For the record I found this: https://en.wikipedia.org/wiki/Horse_gait
Mmmm yeah, after all Horse do have a walk speed barely faster than human... ok then...
Question 2: Though, obviously, their top speed is a lot higher (By that I mean a lot more than 20% faster, more like 250% faster - i.e 3.5 times faster), how does that work in BRP?! 😮 
Question 2a. How about jumping? Apparently world record in 2.4 meters up and 8.4 meters long.... mm... doesn't quite scale like human! 🥴

Yeah, frankly I think you are using the wrong ruleset, or should I say subset of BRP. MOV is a very abstract way of having movement rates that reflects the relative advantage in combat. With humans getting bumped up from MOV 8 in RQ2 to MOV 10 in BRP it reduced the relative advantage of horses. Based on your other threads you probably want something a little more crunchy.

What you might want to look at instead is the Move rating in RQ3. In that version of BRP HUmans moved at 3m per Strike Rake, which doubled to 6 if they were running. Horses had a Move of 10m/SR which is closer to the real world ratios.

 

4 hours ago, Lloyd Dupont said:

Question 2a. How about jumping? Apparently world record in 2.4 meters up and 8.4 meters long.... mm... doesn't quite scale like human! 🥴

No, and it probably shouldn't. What horses are running into is something know as the square-cube law. What that means is that when you double the size of a creature, you cube it's mass, but only square it surface area. Now muscle power (STR) increases with the square, not the cube, so as animals get larger their ability to jump compared to their body weight drops off. That's why a grasshopper can make a standing jump of around ten times it's body length, a human about about  1.15 times it's body length, and a elephant cannot jump at all.

That's all before allowing for the weight of riders.

In game terms what's happening is that each 8 points of STR bumps the jumping distance up by around 2m, but each 8 points of SIZ reduces it by 3. Past a certain point a creature cannot lift it's bulk. That's also one of the reason why we don't have 50 foot tall humans, or man sized insects, and why the largest creatures live in the water. Past a given point, their structures cannot support their own weight.