gets asked quite a lot in the majority of forums. In a lot of cases,
the effects you see in film are cleverly disguised plates of actual
galaxies, with a slight deformation, different angle and positioning
and additional CG elements to give us the impression that we’re
flying around or through it.
As we don’t
yet have the desktop computing power to generate every single star
and dust cloud, we’re going to have to convincingly fake it,
and the best and most obvious way is to use particles. When researching
this subject I noticed that not only do most galaxies come in all
shapes and sizes, their colours and distribution of stellar matter
differ aswell, so therefore there is no proper way to distribute
the particles to create our galaxy.
much reference photography as possible to convincingly create this
effect. You will notice that a galaxy’s colours and detail
change somewhat when the frame is concentrated on a closer area
– dust clouds become more detailed and colourful, stars more
apparent, additional elements like flares, stellar nurseries (etc)
become visible. Although this forms a dramatic picture, we are not
going to go that in-depth as it would take an age to set up and
even longer to render!
solution to creating a successful galaxy is to mix colours. By observing
the reference imagery you will notice that each stream rotating
around the central core does not travel at the same speed. Because
of this, some overlap and their colours merge in places, become
overlaid or react to one another, becoming brighter or darker. The
best way to emulate this reaction would be to use additive or subtractive
transparency. Additive transparency overlays the colour of the background
or additional objects with the colour of it’s own and adds
to the total value. Subtractive does the opposite, therefore matter
streams can be made to appear more dramatic or more subtle this
way by using these transparency types.
galaxy shape will take the form of two main identical streams emitting
from the central core. As both sides are identical, we can concentrate
only on one side, then replicate the particles to form the other
side. Because of our use of facing particles, some elements will
become occluded by others, depending on the angle of the camera.
This can be rectified by either using a different particle type
and therefore material setup, which will increase the geometry count
and therefore the render times, or by repositioning the camera.
distribution method is best suited for stills. Should you wish to
fly around and through the scene you would have to amend a few settings.
As the distribution of the particles is set over a few hundred frames,
you would have to increase the lifespan of the particles, slow them
down considerably and extend their rotation time, therefore generating
the same overall effect but on a much larger timescale. Okay, but
why not simply snapshot the particle system? Yes, this would be
one solution, provided you do not move the camera much. This is
because of the facing particle type; if you reposition the camera
at too much of an angle you will be able to see the sides of the
particles and the gaseous effect will be lost. Also, as the particle’s
opacity and colour are dependant on it’s lifespan, such an
action would therefore render it differently as no particles would
exist in the scene, only geometry. Therefore you would have to amend
the materials assigned to the geometry and change their opacities
to UVW instead of using particle age. Not a simple procedure, but
not overly difficult.
particle system is pretty much the same throughout; just the
materials and rotational tangents are amended. Therefore, create
a Superspray particle system with the settings as illustrated
and animate a rotation of 1440 degrees over 2000 frames. Amend
the Z rotation tangents for frames 0 and 2000 as illustrated.
Label it SuperSpray cloud01
the cloud system and rotate it 90 degrees at frame 0 with animate
turned off. Amend the rotational tangents for frames 0 and 2000
to those different from the original system. This will cause
the particles to overlap slightly. Clone the original system
again and this time rotate by 45 degrees instead of 90. Label
this system SuperSpray cloud redder01. Clone this new system
-90 degrees so you have two “redder” systems at
45 degrees either side of the original.
||Clone the original
system and label it SuperSpray stars 01. Amend the settings
to those illustrated. Create a new Multi/Sub-Object material
and set the number to 5. In the 1st material, label it white
and amend the ambient and diffuse accordingly. Check on Face
Map, Self-Illumination and Additive Transparency. In the Self
Illumination slot, add a Mask map. In the Mask’s mask
slot add a Particle Age map and set it’s colours to White,
White, Black for slots 1, 2 and 3. Set slot 2’s age to
30. In the Mask’s map slot, create a gradient map and
set it to Radial. Back at the top level, clone the white material
to the other slots. Colour each material slightly different
and label accordingly. Assign the Multi/Sub-object material
to the Stars system.
||Create a new material
and label it Vortex Trails. Assign it to the original particle
system. Check on Face Map. Add a Particle Age map to the Diffuse
slot and set colours 1, 2 and 3 to RGB (209,198,128), (191,190,179)
and (106,108,129) accordingly. Set slot 2’s age to 30.
Create another Particle Age in the self-illumination slot and
set the colours to White, near-black and black. Set colour 2’s
age to 40. In the Opacity slot, add a Mask map. Create a Particle
Age map in the Mask slot and set colours 1 and 2 to RGB 45,45,45
with colour 2’s age set to 20, and colour 3 to black.
Create another Mask map in the original Mask’s Map slot
and put a radial Gradient Map in the new Mask’s Mask slot.
Load in the “particle smoke mask – stars.jpg”
map in the Mask’s map slot.
||Clone the Vortex
Trails material and label it Vortex Trails Redder. Assign it
to the SuperSpray Clouds Redder systems. Amend the Particle
Age map’s colours to RGB (91,49,66) , (104,79,124) and
(152,176,175) with Colour 2’s age set to 70. In the Particle
age map in the Opacity slot’s Mask map, set the colour
2 age to 50. Clone this material, label it Vortex Trails Bluer
and assign it to the SuperSpray Clouds Redder system. Check
on Additive transparency and check off the Self-Illumination
slot. Set the Particle Age Diffuse map to RGB (91,49,128) ,
(62,79,124) and (152,176,220) with Colour 2’s age set
||Select all the particles
and clone them. Rotate the clones 180 degrees. Create a camera
and position it as illustrated. Set the camera’s lens
size to the stock 15mm setting. Create an Omni light and align
it to the camera. Create another Omni light and position it
in the centre of the galaxy with the settings illustrated. Exclude
all particle systems from it. Add a Volume Light Atmosphere
and use the settings shown.
||A hell of a lot
of particles later, and here’s our final render. The Volumetric
light works better than a glow to create the central mass and
a wide-angled lens gives a sense of scale to the scene.
you’ve set the scene to render, I’d recommend you go
and make a cup of tea, have a bite to eat, do a spot of laundry,
rotate your tyres and so on. Because this baby is going to take
a hell of a long time to render. To reduce these times, try adding
a set number of particles for each particle system instead of using
a rate. You may also want to knock the volumetric light’s
quality down a notch or two.
Although this illustrates that Max’s own particle system can
handle such a job, you may wish to incorporate additional elements
(such as dust trails) that need to be born from particles. You don’t
have to resort to a third party system to do this; set up your emitter
system and set it’s particle rotation to directional (so the
new particles are emitted in the right direction). Using a Mesher
Compound Object on your original system, create a PArray system
and use the Mesher as the emitter. Simple!
Not satisfied with the additive glows created for the stars within
our galaxy, you could increase them in post by assigning a material
or object ID to them and adding a Glow effect. A Video Post filter
though generates the best results, in which you can easily assign
flares and highlights to these “stars”, as you would
find in images of galaxies.
There are absolutely tons of resources online for researching space
phenomenon. One really good site is the “Astronomy Picture
of the Day” at http://antwrp.gsfc.nasa.gov/apod/ . You will
notice from the many pictures available that galaxies come in all
shapes and sizes. Try adding additional elements to the one illustrated
in the tutorial, such as dust clouds along the outer regions to
match some of the online references…
World magazine, Issue 35, February 2003.
Draper, February 2003. Reproduction without permission