Subject: Re: fire trails a-la back to the future: any ideas?
From: [email-masked] (Brenden Mecleary )
To: [email-masked]
Date: Sun, 25 Feb 1996 08:28:23 -0800

>I'm stumped as to how to achieve this effect with lightwave.   I'm not even
>sure it's a good idea, but it would be the best way for me to do it right
>now.
>
>The goal is to coposite it over a real scene with pavement in it, or, if that
>doesn't work out, something CG, but that would involve more rendering power
>than I have.
>
>--Mike

    Okay, well, here's my idea.  To do this, you need an image sequence of fire, 
from the side, that repeats in a loop (or just goes on for as long as you want).  
Create two polygons in a V-shape with 90 degrees separation.  Put your fire 
texture on as a X-axis map.  You might want to start with the two polygons 
straight up, then morph them to the V position to avoid distortion of the map.  
Use the additive setting on the surface so that you have an easy way of making 
the fire solid but the background transparent(assuming the background is black, 
which it should be).  Then use an animated clip map (much faster than a 
transparency map) to make the tracks appear.  Put a lens flare at the end that's 
appearing to hide the hard edge from the clip map.  So, that's my .02...  But 
first, lemme draw you a diagram...

                     Morph this...           Into this...

                        ||                   \        /
                        ||                    \      /  
     <--x axis-->       ||                     \    /   <--map in this direction
                        ||                      \  /
                        ||                       \/
                                                          Brenden Mecleary
                                                          [email-masked]