PDA

View Full Version : Slit scan Effect



Doctor49152
12-13-2006, 02:13 PM
I remember hearing in one of the LW9 demo videos that with the proper Advanced Camera setting you could do 'rosenman slit scan' effects. Any idea how to set that up.

automan25
12-20-2006, 04:09 PM
Can you give an example of this effect?

cagey5
12-20-2006, 04:15 PM
Try this for starters
http://www.rit.edu/~andpph/text-slit-scan.html

And read about it here..
http://en.wikipedia.org/wiki/Slit-scan_photography

cagey5
12-20-2006, 04:17 PM
But no. I have no idea how to set this up in Lightwave

shrox
12-20-2006, 04:39 PM
I always thought slit scan was a way to eliminate rolling bars when filming a video screen. Guess I learned something new today.

Jarno
12-20-2006, 05:18 PM
Reading the Wiki entry, it doesn't seem to involve anything intrinsic to the camera. It's more like an extreme motion blur. The slit-scan thing is used to overcome the problem that in real life the motion blur length can't be longer than one frame. LW has no such limitation. I think this should be easily possible with the improvements in motion blur that are in 9.2.

---JvdL---

loki74
12-27-2006, 12:14 AM
I always thought slit scan was a way to eliminate rolling bars when filming a video screen. Guess I learned something new today.

I thought that was called scan-matching?


Reading the Wiki entry, it doesn't seem to involve anything intrinsic to the camera. It's more like an extreme motion blur. The slit-scan thing is used to overcome the problem that in real life the motion blur length can't be longer than one frame. LW has no such limitation. I think this should be easily possible with the improvements in motion blur that are in 9.2.

Hmm..

http://www.rit.edu/~andpph/text-slit-scan.html

doubt if motion blur could do some of that stuff...

I really have no clue but this is what it sounds like to me:

Although it IS motion blurring, but not in the familiar sense. It is essentially motion blur in which the temporal location is relative to the spatial location.

Consider a normal frame of motion blur--the shutter opens at time t1 and closes at time t2. While the shutter is open, an object in the frame moves. The resulting image is a combination of all the images showing the object at all of its positions. This is percieved as motion blur.

In the case of a slit-scanning camera, a slit starts at the top of the frame when the shutter opens at time t1. It travels down across the frame, arriving at the bottom at time t2. The result is that the top of the frame shows where the object was at time t1, and the bottom shows where the object was at time t2. Inbetween the top and bottom, then, shows where the object was between when the shutter opened and closed. The result is that objects slant when moved.

If you have access to a copy machine try this: put a paper with some drawing on the copy mahine. Start the copy. Move the paper slowly in the direction perpindicular to the direction the light is moving, as the copy is imaged. The light scanning the image can be thought of as the slit moving across the frame, and the paper obviously is an object in motion.

... i think thats it. could be wrong of course, ha.

TheDynamo
12-27-2006, 12:07 PM
I think that After Effects Pro does it in the current release if you are looking for that effect.

-Dyn

Medi8or
12-27-2006, 06:07 PM
I haven't really looked into it much, but Time sweep in advanced camera options should do this...

willoswald
12-28-2006, 03:40 AM
The advanced info on V9 states that the advance camera can do slit scan and compares to the famed 2001 star gate sequence. So far I have been able to do a kind of hall of mirror effects with the advanced camera but not really what I'm after. The original effect was created with a kind of souped up rostrum camera. The camera wa rolled back and forward on a 15 foot track, shutter open and looking at a slit. Behind the slit was a mixture of artwork and as it scanned across the frame it exposed the smeared image. The real trick to the process was to prgressively move the artwork during the exposure then incrementally move it between exposures. 2D artwork in 3D space plus a time element dor animation. There is a very good description of this in an American Cinematographer article of 1969, if anyone has a link to an online copy of this I wouls appreciate it.