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Old 04-20-2021, 11:10 AM   #11
awesomenessofme1
 
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Default Re: speed range table equation

Quote:
Originally Posted by Ulzgoroth View Post
This is the only place it's inconsistent that way, and seems to be a consequence of the principle that 'a human character's build only has mechanical effects if you want it to'.
The rule is more like "except for very large differences, a creature's SM is based on the size of the race, not the individual."
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Old 04-20-2021, 11:30 AM   #12
Ulzgoroth
 
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Default Re: speed range table equation

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Originally Posted by awesomenessofme1 View Post
The rule is more like "except for very large differences, a creature's SM is based on the size of the race, not the individual."
I don't think I'd call 7 feet and a quarter inch (fits Basic Set spec for Gigantism) a very large difference from 6'11" (fits Basic Set spec for non-Gigantism human). I wouldn't even call it a very large difference from the six-foot 'actually SM 0' human.
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Old 04-20-2021, 11:34 AM   #13
ravenfish
 
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Default Re: speed range table equation

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Originally Posted by Ulzgoroth View Post
I don't think I'd call 7 feet and a quarter inch (fits Basic Set spec for Gigantism) constitutes a very large difference from 6'11" (fits Basic Set spec for non-Gigantism human)
Where an arbitrary cutoff exists, the smallest person above it is always going to be only a tiny bit bigger than the biggest person below it, but 7 feet is certainly very tall for a human (a quick internet search suggests the average American man is about 5 feet 9 inches, so that's well over a foot of excess- quite enough to count as extraordinary in my book).
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Old 04-20-2021, 11:57 AM   #14
Varyon
 
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Default Re: speed range table equation

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Originally Posted by whswhs View Post
I don't think there's a neat way to do this with a spreadsheet, but if you want a fractional modifier, for a number that falls between L and U, you can take

(log X - log L)/(log U - log L)

or

log (X/L)/log (U/L)

and add it to the modifier for L.

So, for example, if X is 2.5, that falls between 2 and 3, so

log (2.5/2)/log (3/2) = log 1.25/log 1.5 = 0.10/0.18 = 0.55

and adding that to 0 (the modifier for 2) is 0.55.
Testing this between 0 and +6 on the table (so between 2 yards and 20 yards), with 50 steps between them (so 10, 10.1, 10.2, etc up to 15), you get pretty good agreement with my suggestion to handle things linearly - the largest difference is between +1 and +2 SSR (3 yards and 5 yards), near the middle of the range - the log method indicates 3.92 would be +1.52 (after rounding), while the linear method instead calls this +1.46. If you want values to within 0.1 SSR, linear should work - if you need more precision, the log method is necessary. Still not sure of a good way to spreadsheet it, but then my spreadsheet-fu isn't that great.
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Old 04-20-2021, 12:19 PM   #15
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Default Re: speed range table equation

Quote:
Originally Posted by ravenfish View Post
Where an arbitrary cutoff exists, the smallest person above it is always going to be only a tiny bit bigger than the biggest person below it, but 7 feet is certainly very tall for a human (a quick internet search suggests the average American man is about 5 feet 9 inches, so that's well over a foot of excess- quite enough to count as extraordinary in my book).
Even then, I wouldn't necessarily call 7' gigantism and 6'11" not gigantism. Having met a number of 7'+ people, I can say there is a difference in long people and big people.
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Old 04-20-2021, 08:23 PM   #16
oneofmanynameless
 
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Default Re: speed range table equation

I'm actually not looking for fractional modifiers, and fractional differences of yards are irrelevant for me.

I have a mechanic in my game where there is a ritual that builds a well of power that grows stronger with every month that the ritual is performed. I wanted a progression that could provide meaningful growth within a few in game months of play, but could also handle hundreds of years of a coven working the ritual and passing the well down. I decided to use the controlled exponential curve of the speed-range table for easy reference. Thus read months maintained as yards on the table and the modifier is the max er value for the well.

So I actually only need to count the number of yards and get a number back. And unlike with range penalties I'd rather round down then up: i.e. 6 months would be 2 max er, instead of 3 max er.

But it sounds like this is going to be a lot more difficult than I thought. =p
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Old 04-21-2021, 09:19 AM   #17
Anaraxes
 
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Default Re: speed range table equation

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Originally Posted by oneofmanynameless View Post
But it sounds like this is going to be a lot more difficult than I thought. =p
Your answer is in post #3.

Most of the other comments are about details of the published table in RAW, which is based on that formula, but rounded a bit. You can round whichever way suits you if you're not keen on matching the printed SSRT exactly.

If your doctor has advised you to cut down on your math intake, then just remember that adding six steps means multiplying by 10. You can change the "six" to anything you like as well. Or the "10", for that matter, to make the multiple of time needed for a certain size increase suit your vision.
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Old 04-21-2021, 10:56 AM   #18
oneofmanynameless
 
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Default Re: speed range table equation

Quote:
Originally Posted by Anaraxes View Post
Your answer is in post #3.

Most of the other comments are about details of the published table in RAW, which is based on that formula, but rounded a bit. You can round whichever way suits you if you're not keen on matching the printed SSRT exactly.

If your doctor has advised you to cut down on your math intake, then just remember that adding six steps means multiplying by 10. You can change the "six" to anything you like as well. Or the "10", for that matter, to make the multiple of time needed for a certain size increase suit your vision.
He hasn't. =p And I was very aware that six steps means multiplying by 10. My math education was just about statistics and I lack the familiarity with logs. Sort of a, "I know generally how this is supposed to work, but lack the knowledge to do the math myself." thing. I've tried the thing in post #3 and it worked great (wrapped in a round function and with a if statement to keep it from going N/A with too low of a number.)
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Old 04-21-2021, 11:09 AM   #19
Varyon
 
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Default Re: speed range table equation

Quote:
Originally Posted by oneofmanynameless View Post
I'm actually not looking for fractional modifiers, and fractional differences of yards are irrelevant for me.

I have a mechanic in my game where there is a ritual that builds a well of power that grows stronger with every month that the ritual is performed. I wanted a progression that could provide meaningful growth within a few in game months of play, but could also handle hundreds of years of a coven working the ritual and passing the well down. I decided to use the controlled exponential curve of the speed-range table for easy reference. Thus read months maintained as yards on the table and the modifier is the max er value for the well.

So I actually only need to count the number of yards and get a number back. And unlike with range penalties I'd rather round down then up: i.e. 6 months would be 2 max er, instead of 3 max er.

But it sounds like this is going to be a lot more difficult than I thought. =p
Nah, that simplifies matters, particularly if you're willing to deviate slightly from the table. In Excel, you can use
=ROUNDDOWN(6*LOG(B1/2),0)
to get your output, with B1 being the field where you type in the number of months (or have it calculated, say for number of years). The deviation points (rounding to the nearest tenth, and only looking at the first part of the sequence) are that +2 starts at 4.4 months (rather than 5), +3 starts at 6.4 months (rather than 7), +4 starts at 9.3 months (rather than 10), and +5 starts at 13.7 months (rather than 15). +0 is still at 2 months, and +1 is still at 3 months; every +6 repeats the above, multiplied by 10 (so +4 starts at 93 months).

I believe the above equation will work for Google Sheets; if not, just find out what their equivalent to the ROUNDDOWN function is and use that instead.

(EDIT: Annnnd I just noticed you already had this solution. Oops.)
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Last edited by Varyon; 04-21-2021 at 11:23 AM.
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Old 04-21-2021, 11:37 AM   #20
maximara
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Default Re: speed range table equation

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Originally Posted by awesomenessofme1 View Post
You're not going to get a broadly usable equation because it rounds differently at different points.
Actually its rounding rules are simple - to the nearest integer

Speed/Range formula: 2 - 6*log(Distance in Yards)

Size formula: 6*log(length in yards) - 2

The GURPS wiki's Size and Speed/Range Table takes the equation to +31 and then gives even larger numbers.

Because it is a log it is easy to extrapolate any value above 15 yd; 10x the value is +6 to the adjustment. So all you really need is 0 through 15 yd and work up from there.

1 yd; -2; +2
1.5 yd; -1; +1
2 yd; 0
3 yd; -1; +1
5 yd; -2; +2
7 yd; -3; +3
10 yd; -4; +4
15 yd; -5; +5
10x; (-6); (+6)

Say you have something 1 mile away.
That is 1700 yds or 1.7 x 10^3
1.7 goes up to 2 which is 0 and you -18 (3x6)
The modifier is -18 for speed or distance

For 12 miles away
12 miles is 20,400 yds or 2.04 x 10^4
2.04 is -1 and you -24 (4x6)
The modifier is -25
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