Posts Tagged 'RPG'



Tutorial – How to Build a Solar System

This is a little deviation from my usual project posts. Instead of showing a project I’ve finished I’ll run through a bit of a Tutorial/How to on designing your own Fantasy/Sci-Fi World Solar system. This is the process I used to design the Sarilo system in the previous post. In looking for this kind of information on the WWW, I pretty much came up blank -everything was either very high level or assumed your world was an earth clone except for the continental layout :). A word of caution: I’m no expert mathematician or physicists so I may have made some liberal assumptions with some of the formulas and maths below, if your reading this blog post for some sort of school project (unless it’s “Build a Fantasy/Sci-fi Solar system”), turn back now.

Jaw Dropping Picture for your Players

First up you’ll need to design  a Solar System layout, how many planets what types etc. If you’re going to all this trouble at some point your going to want to casually insert some kind of picture into your gaming session so the players can go “coooool”. So behold I have assembled the ultimate in solar system development tools, I’m possible over selling it a little. Below is a link to a very basic drag and drop solar system assembly page best viewed at 1280×1024 (+). It uses only CSS and Javascript to run no fancy flash around here :). I checked and it seems to function best in IE7 and 8 (just say yes to allowing active content if your asked). It functions tolerably well in Firefox although changing label names is irritating,  right click them first and then it’ll let you adjust the label name. Go forth and design a Solar System using the below or if your so inclined use Photoshop,  GIMP or something else:

Link to Builder

Link to Builder

Hopefully your back with a semi-pretty Solar system picture to throw at your players. Now we need to flesh out some of the details, how far is each planet from the sun how long does it take to orbit the sun etc. Now if you’ve stuck your habitable planet way out near where Pluto normally sits, now would be a good time to adjust it to somewhere closer to the sun rings 2-4 (possibly 5)are the best places for habitable planets. However it’s your Solar system so feel free to keep it that way but you’ll see the interesting impacts below.

Specify Planet Distance in AU

Don’t get to hung up on how far an AU is.  Just be aware a good range for Terrestrial (Earth like) planets is approximately 0.8 AU’s to 2 AU’s. Earth in our Solar System sits at 1 AU from the sun, Pluto hangs way out at 39 AU and Mercury at a toasty .4 AU’s. Now Assign each planet an AU Distance from the Solar System Star. The planets don’t have to be as spread out as much as our Solar System but do be aware big planets to close to each other could in reality have interesting effects on each others orbits, Feel free to play around with this Solar System builder. I punched in an approximation of the Sarilo System and ran it for a 100000 years (about 4-5 days) with no problem.  It’s interesting to try to create a stable solar system with one planet on an elliptical orbit that doesn’t wipe out your other planets, I have no idea why a comet hasn’t run into Earth yet :).

A little bit of Math

This bit is fairly glossed over, if you want to get into the full workings and understanding feel free to check out  Keplers Laws, for me I’m happy with the below. Basically grab your AU distance for your first planet and place it to the power 3/2, basically 1.5 and you’ll get the orbit of your planet in equivalent earth years. An example My primary planet Etena is 1.24 AU from the Star Ravi, 1.24 to the power of 1.5 equals 1.381 earth years or 504 earth days:

To make things super simple here is an Orbit calculator online (right at the very bottom of the page)or use this spreadsheet I assembled . Using the above does assume certain similarities between our Solar System and the fantasy one but unless you really want to get into some heavy math just live with the above :).

A little bit more Maths

So now you’ve got your planets and you know how many earth days it is to year for each planet. You can just see all your NPC’s running complex mathematical conversions every time they try to calculate what season it is. Time to give your planets unique day lengths etc. I’ll admit I stuck with an hour being 60mins for all the calculations I’m just not that dedicated to make up whole new time system. For each of your planets allocate the number of hours in a day, before giving your earth like planet a 500 hour day, think what impacts this would have on your planets society. I’d recommend to keep your earth like planets hours in a day between 20-30 for easier game play.

Once you have the number of hours in day for a planet  simply take your number of earth days in a year x by twenty four then divide by the number of hours in your planets days, this is the number of the planets days in a year, as an example Etena has 504 earth days in an orbit and 26 hours in a day. 504 x 24 = 12096 hours then 12096/26= 465.2. So there are 465 Etena days in a Year. If you like you can do the above calculation for all your planets. My handy spreadsheet will do these calculations for you :).

Adding the detail from the above

So you now have a Custom Year Calander for your planet which will if you need it to stand up to at least cursory mathematical checking. But what are some of the impacts gamewise? Below is a bit of dot point list of things to consider:

  • If your year is very long (in earth days), the seasons will be longer, more food might need to be stored for winter or a double cropping season might be carried out, plants might mature slower.
  • If your year is shorter (in earth days), plants might mature quicker, as winter is shorter less food needs to be stored.
  • Longer/Shorter Day length could impact working day length etc (shop opening hours)
  • People’s ages will be different younger or older depending on shorter or longer years, maybe you age by each season instead.
  • Certain events could be more or less important, ie if spring comes around every 100 days it’s going to seem less important to celebrate, however if winter is 250 days long your definitely going to have a big party when that’s over.  (or if your planets out by Pluto your whole life might be lived in “winter”)
  • Is your habitable planet closer or further to the sun, this could make it hotter or colder.

Basically think about how things would impact you if the days and years were of different lengths. Now that you know how many days are in your planets year you can design up a calendar for your players to use. Remember to include seasons, approximately one per each quarter of the year.

Hope this information is useful to other people building up a campaign world.

Orbit Calculator – Spreadsheet

Solar System Builder

World Building – Sarilo Star System Tapestry

I’ve been slowly writing and adding to my campaign world setting, I only really work on this when it’s late at night or if I’m very tired. The latest piece I’ve finished up is a solar system map. I decided to start right from the top and work my way down. So I had a feel for the Planets rotational period and year length etc I worked up a Solar System Map and a few Planetary Statistics:

Above is the Original image I assembled using elements from a few different NASA photos and images that NASA have made freely available. The planets are obviously not spaced out to any kind of scale. I’ve made the Sarilo System a dual Habitable planet system, although to start with I’ll only be detailing the Planet of Etena. Once I had the above created I ran it through a few filters to try and get a tapestry effect:

It’s not perfect but it does give the impression of a tapestry, I should have really added some aging like holes and ragged edges, but as it’s supposed to be a one of kind tapestry made by a famous Astromagus. It should be well looked after and protected so aging didn’t seem very appropriate. I pulled together rough statistics for each planet:

Name Sihnon Etena Ilvaya (ilvaya) Ceninia Onayel Aran Tevasi
Position 1st Planet 2nd Planet 3rd Planet 4th Planet 5th Planet 6th Planet 7th Planet
Type Hot Gas Giant Terrestrial (Life) Terrestrial (Life) Frozen/Ice Gas Giant Liquid Gas Barren Rock
Distance from Star 0.41 AU 1.24 AU 1.76 AU 3.2 AU 5.1AU 8.5AU 12 AU
Diameter (KM)
Day Length 7.5 hours 26 hours 27 hours 66 hours 16 hours 13.5 hours 350 hours
Days a Year 304 Sihnon Days 465 Etena Days 757 Hyrokkin Days 759 Ceninia Days 6306 Onayel Days 16081 Aran Days 1040 Tevasi Days
Equiv Earth Days 95 504 852 2090 4204 9045 15173
Moons 0 2 5 1 16 8 0
Rings 0 0 0 0 1 0 0

Assuming I’ve understood it correctly I used Keplers third law to calculate Orbital timeframes and I included an equivalency back to earth days. I realize using Keplers third law wont be a 100% accurate as I’m pretty much assuming that the Sarilo System is then the same as our Solar system but I figure for a Fantasy game setting it should be fine. The other figures are all made up, I’m still working on the Planetary Diameters, need to be a little more careful with those.

As I don’t get to GM very much (or at all any more) and I really enjoy world building I’m just going to do this Campaign world building project as something fun to do when I feel like it. I will continue to add to the world and will make posts here of anything of note. I have begun to upload some of the Info to a wiki but I’m not quiet ready to post the URL as it’s very empty at this stage :).

I’ll get back to Mayhem city and Hinterland builds.

(The layout of my image above was based on this one, although mines a very poor imitation 🙂 . I believe it appeared in or on a magazine cover at some point)

Bugbears (Onemonk bash) – Paper Miniatures

I needed a little bit of a rest from drawing as I was getting a little bit frustrated with my current attempts at drawing my next paper miniatures. I really like Onemonks bugbears but unfortunately their is only one miniature. Bugbears are one of my favorite fantasy monsters so I decided to do a little bit of modification to the existing miniature to come up with four new ones.

I’m not going to detail exactly what I did as it would take to long a post 🙂 . I worked on each variant for about 1-2 hours each trying to make sure I hadn’t corrupted Onemonks artwork to badly and that the fronts and backs still aligned. I ended up with a Gimp file over 2gig in size when open and something around 200 layers for the 4 miniatures , the old computer was really starting to chug at the end. I constructed a:

  • Spiked stick club version, the club was borrowed from a troll,
  • A round mace version taken from Onemonks weapons sheet,
  • A dual weilding axe bugbear, existing axe plus one from the weapon sheet,
  • And a longbow wielding bugbear, I’m unsure if bugbears use bows but it looks good.

I had fun making these as I find bashing and modding much more relaxing than drawing, probably the most disappointing piece is the rear of the shield arm it just looks a little odd, but overall they look okay and the edits are hopefully not to obvious. A picture of the finished  bugbears:

Once again a big thanks to Onemonk for allowing us to mod his figures and change them around. I’ll definitely be putting these into Onemonk’s hoards once they are back up and running.

The GSD and PDF are below, As usual if you save the GSD rename it to .gsd rather than .odt:

Paper Miniature Bugbear(Onemonk mod) – PDF

Bugbear – GSD

Have fun with them.

Redback Spider – Paper Miniatures

I wanted to get some practice sketching up insects so I decdied to make a paper miniature based on a spider. Although not technically an insect I felt the extra pair of legs would just be more practice. Looking around at the different spider species,  I decided to base my paper miniature on the Aussie Redback spider. After several days of practicing sketching spiders in 3/4 view I finally ended up with a bit of rough sketch that resembled what I wanted.  I decided to do something a little different with the spiders as I always liked those miniature packs were you get small and big critters. I thought I’d do two sizes as flat miniatures and a third size as a 2.5d miniature.  Looking at the D&D scale chart I decided on the sizes of  medium, large and huge spiders. As usual I did the outlining and colouring primarily in Inkscape:

I decided to overlay the red strips in Gimp as it has much better control for that than Inkscape. The two smaller flat spiders were fairly easy to design where as the 2.5d Huge spider required a little more work and a pre-final test build to ensure I had the legs the correct length etc. I was hoping the whole lot would fit on  one page but as it turned out that wasn’t possible. The small and medium spiders are on one page and I did mirror each size so there’s 8 spiders on the page. The huge spider is on it’s own page with it’s instructions following it.  Here’s a final shot of the whole family all built up and waiting to devour the next group of adventurers who wander into their nest:

I’m very happy with how these paper miniatures turned out and although the  basing was a little larger than I originally wanted, the medium ones will fit into a 25mm base and two of the larger ones can be trimmed to fit into a 40mm base (Onemonk Bases here). The hair looks much better on print out than it did when looking in Inkscape although if you pick one up and look at it very closely  it does look a little odd.

The GSD and PDF are below, As usual if you save the GSD rename it to .gsd rather than .odt:

RedBack Spider Paper Miniature – PDF

Redback Spider Medium and Large (pg1) – GSD

Redback Spider Huge (pg2) – GSD

Anyways welcome to the parlor said the spider to the fly 🙂


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