There is a space sandbox simulator if you really want that kind of effect with gas...saw it on youtube
tho it doesn't do accretion disks directly, you can immitate them by shredding stars lol
To answer your q's: yes and yes
basically, during system creation when the profile is chosen, it is an accretion disk engine at the beginning
gas? gas physics are present in the comets, the star pushes the gas tail away from the star.
planets form, its based on solids only, ice...rocks..solid. also....some gas are solid or liquid in deep space anyway, no atmospheres yet.
IRL most of the universe is made of hydrogen, doesn't make a good platform for planets.
supernovae create the higher density elements, and that is what these simulated objects represent, without regard to chemical properties and effects.
yes the disks can be formed into rings....every dimensional feature of an accretion is disk is covered if im not mistaking, but im not a scientist so, maybe i missed something.
Directly, it uses these features to form the solar systems:
// SOLAR SYSTEM CONFIGURATION
GLOBAL SPLITWAVE = FALSE // Initial planet formation splits into 2 directions.
GLOBAL SPACEWAVEFORM% = 1 // 0 = direct VECTORADD addition, 1 = random VECTORADD addition ()
GLOBAL RINGS% = 12 // Number of rings
GLOBAL RADS% = 2 // # of radial hub arms
GLOBAL SPREAD# = 12.0 // additional rad spread random angle on xz plane
GLOBAL DIST# = 2000.0 // RADIUS OF PLANET BELT, PER STEP
GLOBAL GAP# = 8000.0 // Magnitude between each ring
GLOBAL G# = 0.000006674 // Gravitational constant - time, the bigger the constant, the faster time goes. our universe irl is very very slow, constant is tiny and thats a good thing.
//PLANET PHYSICS
GLOBAL STARSIZE# = 1000000000.0 // 0 = normal object >0 = star to form in center, size starts at this size.
GLOBAL MaxMASS# = 1100000.0 // RANDOM PLANET MASS MAX START SIZE
GLOBAL MinMASS# = 1000000.0 // RANDOM PLANET MASS MIN START SIZE
GLOBAL VECTORADD# = 0.0 // addition to SPACEWAVEFORM% angle of fall at initialization, 0 = stable, no variationss regardless of SPACEWAVEFORM%,
GLOBAL E# = 120.0 // solar system initial spin speed
Once the system is created and set into motion, its all Master Lord Sir Isaac Newtons Laws of motion in effect.
The algorithms he created and so beautiful, so beautiful they're compatible with computer code.
And to think he designed them 400 years ago without a calculator or computer is mind boggling.
[edit] it also has 3 cams, so far (these so tedious)
1 planet chase cam(not fixed, litteraly chases), 2 star tracking cam, and 3 freemouse cam
Freemouse cam also tracks with star, because it moves sometimes, quickly.