How to make Spacecraft thrusters

Spacecraft thrusters have long been the bane of the amateur striving to get a good effect - in the following tutorial I will endeavor to provide for you a method I have often used to good effect. First we need to give our thrusters some "body" as it were to simulate that afterburner effect that people generally love to see - and to do this we are going to use some of the standard lights that come with LightWave::.

firstly your light needs to be a spotlight and you have to place it like I have below - - note how far forward I have placed the origin of the spotlight - this allows me to constrain the spotlight cone angle to a nice afterburner type effect - I then also eliminate the cone soft edge too or it won't be seen, a 4 degree cone with a 4 degree soft edge will make it invisible!

through trial and error I found these to be the best settings for the cone - .

      

be aware that Viper supports volumetric lights and is excellent for on the fly adjustments of the volumetric light until you are satisfied with it - but you must first make an F9 render for Viper to collect all the volumetric data for you

note in the images where I have placed the height and base of the cone - the base is just in front of the polygon that makes up the thruster vents and the height is for all intents and purposes where the effect will cease.

So what does it look like rendered with ray traced shadows and anti aliasing then?

well as you can see the volumetric lights are not there! - Why? well it's simple when you realise what's happening - the source of the light is hidden! either behind or inside your geometry! so how do you fix this? Go to your Object Properties panel to the lights section tab ...

and tell the object to exclude all of the volumetric cone lights for the rear thrusters - the result?

 

even if you render the volumetric lights in sprite mode like so

it matters very little to the time taken to render these volumetrics - which is to say the least constraining for animation's - if you had a render farm working with a few CPU's at your disposal well go for it - but a single machine - you could be waiting a long time for all these frames to finish rendering!

Is there an alternative?

well yes!

first off the bat I would suggest whipping up some point lights (parented to the objects as required) to make use of their lens flare options in order to give your thrusters some life like so:

these look fairly good - but not really indicative of a good high powered thruster outlet. We could duplicate the lights to make them brighter or alter their settings to make them brighter - but what we would get is exactly that -- brighter points of light - and not an illuminated thruster vent - which is what we are after...

so next I would suggest whipping up some luminosity maps for the thruster vents - (which just needs some simple work in Photoshop to achieve by working on a copy of the diff map already used) and then place that in the luminosity channels for the thruster vents with a bit of post process glow effect and we'll get something like this with just the luminosity maps and the point lights taken away...

out of interest what would the thrusters look like when animated by purely using the luminosity maps as the light source?
let's have a look...

well that's not that bad... even looks good as the engines fade with distance with a nice dwindling twinkling effect - but.. Well it's not really bright enuff is it? So now if we combine the lens flares with our luminosity maps what would we get?

the question now is what does this look like when animated - now I have to mention that I have given the rear point lights lens flares a fade with distance option and the nominal distance is about 30 m - which should be sufficient otherwise we would just get the flares staying mega bright even as they disappeared into the ether.. What does it look like then....

 

whoa!! What happened there then!? The flares dwindled like they should have and then everything got brighter and the fury looked like it exploded?

well I can say this puzzled me for a while too until I realised what was happening. The front thruster lights had flares set that had the fade behind objects options on - and you would theorise that as they were hidden they would never show?

Well lens flare is a post render process and as the fury got further and further away the geometry became virtually non existent - in particular "smaller" than the basis for the post render process and the front flares became more and more visible again!
The solution was to enable them with the same settings for their fade with distance as for the rear flares - and the result was satisfactory:

 

as you can see as the flare dwindles away to nothing in the distance the glow effect comes into play and because the glow is generally around 8 pixels it does enuff illuminating to carry on the effect of the thrusters whilst far away in the distance

what is the benefit of all this extensive setup with the flares? Well almost a 60% decrease in render times as opposed to the volumetric method!! Which means faster renders and quicker animating times - and it looks just as good - well in my book anyway.

One last tip - again another time saver - grab your manual and read up on the vector blur plug-in..

Compared to normal motion blur and especially motion blur that is dithered - vector blur offers extreme decreases in render times on a per frame basis and looks better if not equal in the majority of standard cases you'll encounter.

Trouble with standard motion blur when dithered is that LightWave will render the frame - than take the objects that are moving within that frame and based on their speed render more instances of them and partially overlay them onto the frame positionally between the start point and the start point of the next frame. This gives the STAGGERED look sometimes visible in many films and animation's. And it takes ages to render too.

Vector blur doesn't - it a single post render process much akin to motion blur filter in Photoshop and is a LOT faster!

there is very little difference as these two show

standard motion blur 

vector blur