Cycles stars !

Support Materials and Textures
41

also depends where you are and amount of stray light from cities / buildings

but if far from city lights you can see some galaxies/nebula clouds with a little bit of color but your right not much
and not photo realist at all
even pics from NASA are not realist all are color enhanced

I was thinking more from a CG point of view !

and if possible mostly with procedural textures
I can make a nodes script to do it later on

happy cycles

42

A few suggestions (from an astronomer).

  1. Your stars are too big - they should be (as close as possible) point sources. In practical terms they should be no more than 1 pixel wide in your image. If you want to make them appear to glow - use compositing to add a diffuse glow or diffraction spikes (see my image below).
  2. The ratio of bright to faint stars could be teaked. Generally speaking you get exponentially more stars the fainter you go. The table in the wikipedia article below shows that for each drop in magnitude - you get about 3-4 times as many stars as the one before it.
  3. Your nebulosity is ok structure wise - You don’t need a central star with that type of nebula. The type of nebula that has a central star is a planetary nebula. These generally appear round or spherical and are formed by a star throwing off its outer layers. What you have above is an emission (or reflection) nebula which is caused by gas and dust contracting under its own gravity. You do often get stars embedded in such a nebula - but the don’t have to be in the centre.
  4. The colour of the nebula may need some work. The colour of the nebula depends on whether you are trying to simulate what the eye would see - or the true colour of the nebula. Emission and reflection nebulae have different colours (usually red, blue or green depending on which element being ionised). If you want to simulate what the eye would see - bold colours are generally out. The eye would normally see a diffuse nebula like that as a pale grey - or if there is any colour at all it would appear pale green (as that is the colour the human eye is most sensitive to).

stars.png800×600 1.8 KB

43

Not with the naked eye you cant. Even from the darkest site on earth - you wont see any nebulosity aside from the odd slight smudge. One of the brightest nebulas visible from earth is the Orion nebula - and even that looks like nothing more than an out of focus star with the naked eye. Its also pretty small - you can cover it entirely with the tip of your finger held at arms length.

To see any colour in that nebula you need to use a 10 inch scope as an absolute minimum and even then its the merest hint of pale green. Human colour rendition in low light simply isn’t up to the task.

Agree - but what is aesthetic from a CG point of view isn’t necessarily “realistic”.

44

for some bright stars you could also use the new volume scatter to give a little bit of halo may be

happy cycles

45

Realism in space art is boring. Lets face it…
I recently tried my hand at some space art and went the realism route and quite frankly, it was boring for the most part.
I then started looking at good space art stuff and they had a lot of things that weren’t scientifically correct, but was pretty nice to look at.

46

I’d probably agree in a lot of cases, afterall most of the nice pictures we see from NASA etc aren’t “realistic” representations…but then again…I didn’t bring up the subject of realism :wink:

As far as pure CG/artistic aesthetics go, anything…erm…goes :smiley:

47

This http://paulbourke.net/miscellaneous/starfield/ is an interesting page with a database of the 9000 brightest stars in the earth sky.

NASA provide also these maps http://maps.jpl.nasa.gov/stars.html, very useful!

48

In fact one of my ideas is also to procedurally create an alien star scape. :slight_smile:

49

I agree. :slight_smile:

50

it would be interesting to have a small database of real stars to simulate the real stars function of location
if it does not exist yet !

happy bl

51

@RickyBlender The map is given here already - http://paulbourke.net/miscellaneous/starfield/stars.c

52

what kind of map this is
which soft do u open it ?

got problem with download on IE11

I was thinking more like a database list for stars function of magnitude may be
that you can add in the blender world
function of location and time

thanks

53

ok I found how to get it as txt or py file
first file has like 9000 stars which is a lot
might be able to filter function of magnitude may be
will see if I can find a script for calculating the RA and DEC from location and time

thanks

54

Inspired by the discussion about realism I did some more exploration and I come out with this result. I really simplified all the previous work and now I came out with a setup that permits to control the quantity of stars, their scale (that results in a different apparent magnitude) and their distribution in the sky dome.

upload.png960×540 707 KB

This setup also contains Compositor nodes, like Blur and Glare to add some more “realism”. It can be possible to get more “realistic” results tweaking parameters of both, Material nodes and Compositor nodes.

The screenshots of the nodes setup.

upload.png1575×480 93.5 KB


upload.png985×378 95.9 KB

And the blend file: https://www.dropbox.com/s/ukieff69y5rn6lr/starfield%20copia.blend

55

did u read all the stars and how was it added ?

happy cycles

56

What? I do not understand.

57

sorry u did proc texture

I thought you read the file with 9000 stars !

I’m trying to prepare a script to read these stars and add some filter
not certain what it will give

happy bl

58

nice pics

you use proc textures with colors for stars

I will try to add some proc color stars also in script

but first want to get real stars around earth and not much color !

thanks

59

Another way to do this is to create an icosphere object and give it an emission material with a strength of 1. Then make a plane with a particle emitter using the icosphere object as the emitter (render->‘object’).


http://www.pasteall.org/blend/28101

Though you will probably want to mess around with the star layer in the compositor to get the exact glowy effect you are looking for.

edit: jesus christ I did not realize how old this thread was, lmao.

60

@mikepan has posted some scenes inhis blog, including one galaxy made with cubes. You can download it there.