As I'm sure most of the regular readers have probably noticed, the last few issues of "FlightWave" have been taking a little longer than usual to get out.  This issue signifies the longest wait of all!  The reason is quite simple; no one's been submitting any articles.  "Without the support of others, the mag can't even breathe let alone survive" says a certain editor - so, always ready to do my part, I decided to submit a few tutorials just for the hell of it.  A lot of you will probably know me from the up and coming Babylon 5 Modeler's Guild (or B5MG for short) which I have helped to create along with several other talented modelers.  But, for those of you who don't, then hi!

So, what am I going to write about, you say?  That question was on my mind quite a bit recently - I had thought about doing a tutorial on building a space ship, but that has already been done to death on the net.  Then it occured to me, what is the one thing which is a little hazey in terms of tutorials on the net?  

Special effects.

Yes, we've all seen those really cool SFX shots from programs like Star Trek:Voyager, Deep Space Nine, and of course the great Babylon 5.  But, have any of you ever wondered how in the blazes they do it?  I bet some of you have probably even tried (a few with success) to immitate those shots.  Well, this article is the first in a series - penned by yours truly - focusing on how to recreate just those effects.

This month, we focus on cloaking and decloaking objects.

From the very first Romulan ships, which for some strange reason looked just like their Klingon counterparts, right up to the latest Defiant class starship, the cloaking ability has been a big feature in the Star Trek universe.  Not only that, but as of late more and more film and television shows are featuring people, objects, or ships with the ability to mask themselves from either the human eye, or high-tech sensors.  And who's job is it to make these effects look so damn realistic?  You guessed it, the Computer Graphics Artist.  So, without further ado, I'll jump right into how this particular task can be pulled off in Lightwave.

First things first.  Obviously, before you do anything, you've got to decide just exactly what object you want to use for the cloaking effect.  It doesn't really matter what it is; be it a simple square box to a highly detailed space ship.  However, some objects tend to look far better when cloaking than others.  So, with this in mind, and having already mentioned the Defiant, I decided to use that one - for those of you wanting to get hold of a copy, there's a download link included at the bottom of this article.  I'm unsure as to who the creator of the model is, since it is only credited as 'Unknown' on the 3D Review webpage, but I have a feeling that my close friend Mark Kane is the perpetrator... If you know otherwise, please let me know!

Load your selected object into Lightwave, and experiment a bit to find a good viewpoint for the camera.  Keeping in mind that this object is going to dissapear, it's probably a good idea to rig up some lights which give a reflection off one of the object's sides.  Another good idea is to place some kind of object behind the one you actually want to cloak, since it adds a great amount of depth to the scene and also serves to further enhance the cloaking effect.  The best thing to use is some kind of nebula, or planet since they're both astronomical bodies which will also add realism to the shots.  

To make it appear as if the ship is disappearing, what's necessary is to utilize the Object Dissolve settings (See Fig 2).  If you think back to those experiments you used to do back in Chemistry lab, you'd add water to a chemical in order to dissolve it.  The more water you added, the more dissolved it became.  The same is true here, in the analogy that you are adding virtual air to the model.  So, the more 'virutal air' you add, the more dissolved it becomes.  The automatic setting for object dissolve is 0%, meaning that no 'virtual air' has been added, and so absolutely no dissolving can occur.  I use this analogy of 'virtual air' merely as a way of explaining the Object Dissolve function to less experienced Lightwave users.

Click on the Object Dissolve, and change the settings a few times to experiment.  The higher the value, the more dissolved the object becomes, as shown below:

Because what we're after is an animation, and not a single image, simply setting the value in this manner will not suffice.  Instead, it's essential to make us of the Envelope function (see Fig 2.).  An Envelope basically allows you to set different settings for different time periods, almost like the Key function in layout allows you to set different motion settings for different time frames.  First, select a starting value for the Dissolve (which should normally be 0%), then decide how much time you want the object to take before it completely (or partially) dissolves, and change this time frame to the required Dissolve setting (i.e. 100%).  

In my animation (see Fig 6.), I've got the Defiant 0% dissolved (fully visible) from time frames 0 to 15.  The reason I leave it on 0% for 15 frames is to allow the viewer of the animation a chance to see the defiant in its full glory before it actually cloaks.  I then set frame 60 to 100% dissolve, which will act as the final frame in the animation.  Don't forget that you can also play around with the Spline Controls if you want to add some tension to the envelope, or simply make it a linear transition.  It may take a few times to get the look and feel just right, so you may need to experiment a little.

Right, so now you've got the ship to dissolve out of reality, but doesn't it always looks a whole lot cooler than that on Star Trek.  Whenever a ship cloaks (or decloaks), it seems to warp space in some way, doesn't it!  Don't lose sleep over it, all we need to do is add a Displacement Map - it's that simple.  

Once inside, you're confronted with what should look like this:

The most important features of the Displacement Map are the Texture Type, and Texture Amplitude.  Firstly, you must decide which Texture Type you want to use; Ripples, or Fractal Bumps.  Choosing Ripples will give it a rippling effect, almost like water, while Fractal Bumps is a more blocky effect.  I've applied both effects to a simple box in order to demonstrate the differences:

For the Defiant, I chose the Rippling effect, simply because it gives a more realistic space warp than the fractal bumps.  Next, we change the Texture Amplitude, which specifies by how much the model is distorted.  Again, it is a linear scale from 0, for no distortion, to any higher value.  Now because we want to have the ship begin cloaking at frame 15 and disappear by frame 60, it is once again necessary to utilize an envelope.

I've once again set frames 0 to 15 at zero, with frame 60 having a displacement setting of ten.  Ten is actually quite a high value, and were it another model it may look odd, but for the Defiant mesh it's perfect.  However, just having a displacement of ten is never enough, it is also a combination of the Wavesources, Wavelength, and Wave Speed settings which can really make the difference.  The Wavesources option is exactly what it says, the number of wave sources which are applied to the model; the higher the number of wavesources, the more waves there are.  Wavelength is the length of the waves, and Wave Speed obviously the speed of them.  Having experimented with a number of settings myself, I actually found that leaving these in their original settings, and merely changing the displacement value gave the best effect (but only for this model; remember that because other models are shaped differently, not all settings will have the same effect on them as you want, which is why it's always a good idea to play around for a while until you finally find the best values).

And that's basically all there is to it!  Now that both the Object Dissolve and Displacement Maps are applied, you can render the animation and Et Voila!  I found that rendering from frames 0 to 70 gave the best effect, since the first 10 or so frames allows the viewer to see the Defiant before it cloaks, and the last 10 to see empty space in its place.  Just in case you want to cross reference with my animation, I've included an .avi file for download.

Oh, almost forgot.  I've concentrated on cloaking objects here, but if you want to decloak them, all that's needed is to simply reverse all the settings.  In other words, start frames 0 and 15 at 100% dissolve, 10 displacement, and set frame 60 to 0% dissolve, with 0 displacement.  It really is that simple!

Well, that's it for this installment.  I hope many of you, both experienced and not so, found some of the information contained in this article useful.  If you did, send me an e-mail - if you didn't, hell send me one anyway.  

Happy cloaking.

Download:

Defiant Model

Defiant Animation

Alexander Shareef is a freelance writer and graphics artist/animator, and is the founder of the up and coming Babylon 5 Modeler's Guild (B5MG).  Contact him via E-mail at:Shareef@Mailcity.com