No More Exams!!
Finally the end of exam-idge!
Just saw this ace effect on the extras of the LotR extended edition DVD, called Optical Flow. Basically you use the brightness values of a greyscale video/image as a basis to displace another video or image. For example in LotR, the scenes where Frodo puts on the Ring, and the whole world changes into this weird wispy kind of effect. To achieve this they would have used a video of some fire, converted it to greyscale and then used its brightness values to displace the video of Frodo’s view of the world. It’s also a bit more complicated - they use some kind of technique called particle billboard or something, where a particle system is used to drive the video of fire.
OK! So now that I’ve successfully confused you, here’s a video I made of what I mean:
Click here to view (120Kb, Quicktime MOV)
Right, so now you know what I’m on about, you may be wondering how I did it, ey?
Blender! Using the Displace node (coded by Matt Ebb - cheers!), I realised that this optical flow type effect could ACTUALLY be done in Blender!! Here’s a screenshot of my node setup:
For the video I used some free fire footage, from the good folks at detonationfilms. Basically I fed the fire footage into the “Vector” input of the Displace node, and just used a simple rendering of a cube as the image to be displaced. Also an interesting way of checking what the displace node is doing, is generating a “UV test grid” and applying the displacement to that:
Anyway, now that I’ve got more time I’m hoping to get this effect to work to the same extent that they used it in LotR - should be a good challenge!
Another thing… I was a bit bored of revising the other week and so I decided to write a script inspired by the “Look Around You” series. Basically its a spoof of all those cheesy old education videos (like Physics in Action!), called “Look to the Future”. Anyway I though I might as well upload it:
Click here to view (PDF, 7Kb).
Oh yeh, I forgot to mention the most obvious piece of news! NEW THEME!!
Hopefully I’m gonna finish making those 2 music videos I mentioned before as well!
June 22nd, 2007 at 3:26 am
Cool
BTW you can get a smoother result by giving the displacement input (the fire) a few pixels blur before it goes into displace.
June 22nd, 2007 at 11:57 am
Thanks for the comment, Matt!
Blurring the fire could be a good idea, although I think the slightly harsh effect could be used as an advantage, obviously depending on the “mood” of the final shot.
Now all I’m trying to do is apply this to some live action footage. I need to find a way of duplicating/controlling the fire footage via particles. Jahka’s particles should do the trick - if I figure out how to use them without crashing!