DayTrippers Planet Generation System

Apr 17, 2025

The interstellar destination below was created using the DayTrippers Planet Generation rules (now in beta testing). Click here to generate another one.

0) {
$planetCount += rand(1,6);
$planetCountDice–;
}
return $planetCount;
}

function planetSize($planetMod) {
$planetSizeArray = array(“”, “”, “Small Rock Planet”, “Small Rock Planet”, “Asteroid”, “Moon”, “Artificial Satellite”, “Medium Rock Planet”, “Large Rock Planet”, “Gas Giant”, “Gas Giant”, “Gas Giant”, “Rogue Planet”);
$gravityModArray = array(0, 0, -3, -3, -3, -5, -2, -1, 0, 5, 5, 5, -3);
$planetSizeRoll = rand(1,6) + rand(1,6) + $planetMod;
if($planetSizeRoll < 2) { $planetSizeRoll = 2; } if($planetSizeRoll > 12) {
$planetSizeRoll = 12;
}
$planetSize = $planetSizeArray[$planetSizeRoll];
$gravityMod = $gravityModArray[$planetSizeRoll];
return array($planetSize, $gravityMod);
}

function gravity($gravityMod) {
$gravityBase = 0;
$divide = 0;
$gravityArray = array(“”, “”, “12”, “12”, “12”, “11”, “11”, “1”, “2”, “2”, “2”, “4”, “4”, “4”, “6”);
$atmoModArray = array(0, 0, -2, -2, -2, -1, -1, 0, 3, 3, 3, 5, 5, 5, 6);
$gravityRoll = rand(1,6) + rand(1,6) + $gravityMod;
if($gravityRoll < 2) { $gravityRoll = 2; } if($gravityRoll > 14) {
$gravityRoll = 14;
}
$gravityVal = $gravityArray[$gravityRoll];
if($gravityVal > 10) {
$gravityVal -= 10;
$divide = 1;
}
while($gravityVal > 0) {
$gravityBase += rand(1,6);
$gravityVal–;
}
if($divide) {
$gravity = number_format(1 / $gravityBase, 2);
} else {
$gravity = $gravityBase;
}
$atmoMod = $atmoModArray[$gravityRoll];
return array($gravity, $atmoMod);
}

function atmosphere($atmoMod, $gravity = 1) {
$atmoArray = array(“”, “”, “Atmosphere is escaping the planet”, “Atmosphere is escaping the planet”, “Atmosphere is escaping the planet”, “Extremely thin, no Oxygen”, “Chlorine”, “Carbon Dioxide”, “Nitrogen/Oxygen with heavy gases, Propane, Butane”, “Dense Air (Nitrogen/Oxygen)”, “Nitrogen/Oxygen with Ozone in Stratosphere”, “Nitrogen/Oxygen with trace toxins”, “Ammonia & Methane”, “Hydrogen & Helium”, “Exotic toxic gases”);
$waterModArray = array(0, 0, -6, -6, -6, -6, -4, -3, -2, -1, 1, 0, -4, -5, -6);
$atmosphereRoll = rand(1,6) + rand(1,6) + $atmoMod;
if($atmosphereRoll < 2) { $atmosphereRoll = 2; } if($atmosphereRoll > 14) {
$atmosphereRoll = 14;
}
$atmosphere = $atmoArray[$atmosphereRoll];
$waterMod = $waterModArray[$atmosphereRoll];
$pressure = $atmosphereRoll * $gravity;
return array($atmosphere, $waterMod, $pressure);
}

function water($waterMod) {
$waterArray = array(“”, “”, “No standing water”, “Arid rock/desert world, very little standing water”, “Arid rock/desert world, very little standing water”, “Arid rock/desert world, very little standing water”, “Semi-Arid world, water frozen or beneath surface”, “land”, “land”, “Ocean world”, “Water vapor makes up most of the atmosphere”);
$waterRoll = rand(1,6) + rand(1,6) + $waterMod;
if($waterRoll < 2) { $waterRoll = 2; } if($waterRoll > 10) {
$waterRoll = 10;
}
$water = $waterArray[$waterRoll];
return $water;
}

function climate() {
$climateArray = array(“”, “”, “Frozen solid; ice & rock”, “Frozen solid; ice & rock”, “Arctic conditions”, “Arctic conditions”, “Cold”, “Temperate”, “Hot”, “Greenhouse conditions”, “Greenhouse conditions”, “Wildly variable”, “Hellish”);
$precipDLArray = array(0, 0, 0, 0, 5, 5, 6, 7, 9, 8, 8, 5, 10);
$climateRoll = rand(1,6) + rand(1,6);
if($climateRoll < 2) { $climateRoll = 2; } if($climateRoll > 12) {
$climateRoll = 12;
}
$climate = $climateArray[$climateRoll];
$precipDL = $precipDLArray[$climateRoll];
return array($climate, $precipDL);
}

function biosphere() {
$biosphereArray = array(“”, “”, “Biotoxins in atmosphere”, “Biotoxins in atmosphere”, “No life”, “No life”, “Proto-organisms in suspension”, “Proto-organisms and non-mobile lifeforms”, “Non-sentient lower lifeforms”, “Sentient lifeforms”, “Sentient lifeforms”, “Highly evolved lifeforms”, “Highly evolved lifeforms”);
$biosphereRoll = rand(1,6) + rand(1,6);
$biosphere = $biosphereArray[$biosphereRoll];
return $biosphere;
}

/* BIDNEZ */

$starIndex = 0;
$starType = ‘Star’;
$stars = array();
$planetName = planetName();

$starSizeData = starSize();
/*
$stars[0][‘starSize’] = $starSizeData[0];
$stars[0][‘colorMod’] = $starSizeData[1];
$stars[0][‘planetMod’] = $starSizeData[2];
*/
$starSize = $starSizeData[0];
$colorMod = $starSizeData[1];
$planetMod = $starSizeData[2];

$starColorData = starColor($colorMod, 0); // 1=forcespecial 0=dont
$starColor = $starColorData[0];
$planetCountDice = $starColorData[1];
if($starColor == ‘Special’) {
$starSpecial = specialStar();
$starType = $starSpecial;
switch($starSpecial) {
case ‘Dwarf’ :
$starSize = ‘less than 0.1 times ‘;
$starType = ‘Dwarf Star’;
$starColorData = starColor(0);
$starColor = $starColorData[0];
if($starColor == ‘Special’) {
$starColor = ‘Black’;
}
break;
case ‘Cluster’ :
$starType = ‘Star’;
$starIndex++;
$starColorData = starColor(0);
$starColor = $starColorData[0];
if($starColor == ‘Special’) {
$starSize = ‘- tiny compared to ‘;
$starType = ‘Neutron Star’;
$starColor = ”;
}
break;
case ‘Nova’ :
$starSize = (rand(1,6) * rand(1,6) * 10) . ‘ light-years across’;
$starColor = ”;
break;
case ‘Brown Dwarf Star’ :
case ‘Pulsar’ :
case ‘Quasar’ :
case ‘Black Hole’ :
$starSize = ‘- tiny compared to ‘;
$starColor = ”;
break;
default :
$starType = ‘Star’;
break;
}
}
$stars[0][‘starSize’] = $starSize;
$stars[0][‘starType’] = $starType;
$stars[0][‘starColor’] = $starColor;

if($starIndex) {
while($starIndex > 0) {
$starSizeData = starSize();
$starSize = $starSizeData[0];
$colorMod = $starSizeData[1];
$planetMod = $starSizeData[2];
$starColorData = starColor($colorMod);
$starColor = $starColorData[0];
// $planetCountDice = $starColorData[1];
if($starColor == ‘Special’) {
$starSpecial = specialStar();
$starType = $starSpecial;
switch($starSpecial) {
case ‘Dwarf’ :
$starSize = ‘less than 0.1 times ‘;
$starType = ‘Dwarf Star’;
$starColorData = starColor(0);
$starColor = $starColorData[0];
if($starColor == ‘Special’) {
$starColor = ‘Black’;
}
break;
case ‘Cluster’ :
$starType = ‘Star’;
$starIndex++;
$starColorData = starColor(0);
$starColor = $starColorData[0];
if($starColor == ‘Special’) {
$starSize = ‘- tiny compared to ‘;
$starType = ‘Neutron Star’;
$starColor = ”;
}
break;
case ‘Nova’ :
$starSize = (rand(1,6) * rand(1,6) * 10) . ‘ light-years across’;
$starColor = ”;
break;
case ‘Brown Dwarf Star’ :
case ‘Pulsar’ :
case ‘Quasar’ :
case ‘Black Hole’ :
$starSize = ‘- tiny compared to ‘;
$starColor = ”;
break;
default :
$starType = ‘Star’;
break;
}
}
$stars[$starIndex][‘starSize’] = $starSize;
$stars[$starIndex][‘starType’] = $starType;
$stars[$starIndex][‘starColor’] = $starColor;
$starIndex–;
}
}

$planetCount = planetCount($planetCountDice);
$romanArray = array(”, ‘I’, ‘II’, ‘III’, ‘IV’, ‘V’, ‘VI’, ‘VII’, ‘VIII’, ‘IX’, ‘X’, ‘XI’, ‘XII’, ‘XIII’, ‘XIV’, ‘XV’, ‘XVI’, ‘XVII’, ‘XVIII’);
$planetNumber = rand(1,$planetCount);
$romanNumber = $romanArray[$planetNumber];

$planetSizeData = planetSize($planetMod);
$planetSize = $planetSizeData[0];
$gravityMod = $planetSizeData[1];

$gravityData = gravity($gravityMod);
$gravity = $gravityData[0];
$atmoMod = $gravityData[1];

$atmosphereData = atmosphere($atmoMod, $gravity);
$atmosphere = $atmosphereData[0];
$waterMod = $atmosphereData[1];
$pressure = $atmosphereData[2];

$water = water($waterMod);
if($water == ‘land’) {
$watercover = (rand(1,6)+3)*10;
$landcover = 100 – $watercover;
$water = $landcover . ‘% land, ‘ . $watercover . ‘% water’;
}

$climateData = climate();
$climate = $climateData[0];
$precipDL = $climateData[1];

$biosphere = biosphere();

/* DISPLAY */

echo ‘STELLAR SYSTEM ‘ . strtoupper($planetName) . ‘
‘;
$i = 1;
switch(count($stars)) {
case 5 :
echo ‘Pentary System:’;
break;
case 4 :
echo ‘Quadrary System:’;
break;
case 3 :
echo ‘Trinary System:’;
break;
case 2 :
echo ‘Binary System:’;
break;
default :
break;
}
foreach($stars AS $thing) {
if(count($stars) > 1) {
echo ‘
‘ . $i . ‘. ‘;
}
if($thing[‘starColor’] AND $thing[‘starColor’] == ‘Orange’) {
echo ‘An ‘;
} else {
echo ‘A ‘;
}
if($thing[‘starColor’]) {
echo $thing[‘starColor’] . ‘ ‘;
}
echo $thing[‘starType’] . ‘ ‘;
echo $thing[‘starSize’];
if($thing[‘starType’] != ‘Nova’) {
echo ‘the size of Sol’;
}
$i++;
}
echo ‘
‘;
echo ‘with ‘ . $planetCount;
if($planetCount == 1) {
echo ‘ planet in orbit.
‘;
} else {
echo ‘ planets in orbit.
‘;
}
echo ‘
‘ . strtoupper($planetName) . ‘ ‘ . $romanNumber . ‘
‘;
echo ‘TYPE: ‘ . $planetSize . ‘
‘;
echo ‘GRAVITY: ‘ . $gravity . ‘ G
‘;
echo ‘ATMOSPHERE: ‘ . $atmosphere . ‘
‘;
echo ‘PRESSURE: ‘ . $pressure . ‘ Earth atmospheres
‘;
if($planetSize != ‘Gas Giant’) {
echo ‘WATER: ‘ . $water . ‘
‘;
}
echo ‘CLIMATE: ‘ . $climate . ‘
‘;
echo ‘PRECIP DL: ‘ . $precipDL . ‘
‘;
echo ‘BIOSPHERE: ‘ . $biosphere . ‘
‘;

?>


‘;
?>

DayTrippers is a Surreal Science Fiction Reality-Hopping OSR RPG. Now available at RPGnow.com.

Explore More Insights

Carl Jung

Carl Jung

"The images of the unconscious place a great responsibility upon a man. Failure to understand them, or a shirking of ethical responsibility, deprives him of his wholeness and imposes a painful fragmentariness on his life." Field: Psychiatrist.Born: 26 July 1875,...

read more

Custom System Query

Let’s talk about what you want your system to do, not what it forces you to do. Custom modules provide advanced features, making you stand out in both design and functionality.

• system design
gamification, modeling, data normalization
• system documentation
composite designs, object specifications, function specifications
• end user documentation
general audience, technical audience

read more

Character Development Query

Original Characters, Avatars, PFPs, digital art and narrative-based marketing campaigns, utilizing the magic of social media and direct interaction to engage with your customers.

• character design
avatars, rpg characters, 2D or 3D character art
• character modification
photobashing, costuming, product placement
• character narrative
art, writing, editing, sequencing

read more