Topic awaiting preservation: Forgive the silly question.. (Page 1 of 1)

I've been lurking in the wings over the past week or so, ever since I found these forums, and I'm quite interested in the Power Distort topic, among other things.. But I keep feeling like I'm missing something. It talks about a "Zoom Cube", and when I search for it, I find references to "Tech-Slop".. But doesn't help me terribly much. I'd really like to understand what's going on - I can follow most of what warjournal's explaining - but I can't really follow along, because I don't understand where he's getting the numbers. I'm assuming it's something to do with the Zoom Cube.. Which, as I said, is still a mystery to me.

Anyone care to enlighten this poor soul?

http://twysted.net

TwystNeko: Welcome. Why not ask in the Power Distort thread?:
http://www.ozoneasylum.com/Forum3/HTML/003734.html

wj is always happy to have feedback on his tutorials

Nice balloons by the way You might also want to nip along to the Reception Room for urmmmmmmm 'induction' - see link in sig.

[edit: And there is no such thing as a silly question only sill answers Well thats not strictly true as I have seen some pretty silly questions (mainly about rythmic buttock slapping) this just isn't one of them]

___________________
Emps

The Emperor dot org

Oh, man. I need more time for this!
Power went out last night after the tornado and everything is a mess.
But I do have time for a cup of coffee and to make my rounds, heh.
Back when I can.

For Technical Slop in general, I recommend starting at the very beginning. See Table of Contents. For a newcomer to Tech-Slop, I recommend glancing over the first 25 pages or so just to get a general feel for the site and how I do things. Then, slowly take it one page at a time - and I do mean slow.

You can find out about the Zoom Cube here:
The Cubes
That is the 3rd page with some specifics. Feel free to go to the 1rst page and start there: Gradients.

In Power Distort, I do use some numbers. Nearly all of my numbers are centered around 256 in one way or another. This is because a gradient has 256 levels from black-to-white.

Ummm...

TwystNeko: Glad to see you in the asylum. What don't you understand with displace maps ? the distortion itsefl ? the way to control it ? the "Zoom Cube" ( TM of warjournal ) ...

Well, let's try to give an explanation of the displace filter. As you already know, it picks the pixel somewhere according to the displace map. The fundamental is that the red component of the displace map codes the horizontal offset, the green one codes the vertical offset, and the blue one codes ... nothing. The intensity of the components is in the range [ 0 ; 255 ], but Adobe and the Photoshop zealots wanted to be able to picks some pixels on both sides ( positive and negative ) so to get the offset of the pixels you substract 127 to its intensity to shift it in the [ -127 ; 128] range, thus :

.a medium red ( @ 127 ) means : pick the pixel 127 -127 = 0 pixels on the right
.a red @ 209 means : pick the pixel 209 -127 = 82 pixels on the right
.a red @ 31 means : pick the pixel 31 -127 = -96 pixels on the right = 96 pixels on the left

.a medium green ( @ 127) means : pick the pixel 127-127 = 0 pixels below
.a green @ 193 means : pick the pixel 193 -127 = 66 pixels below
.a green @ 71 means : pick the pixel 71 -127 = -56 pixels below = 56 pixels above

When you combine a red and a green component, you can pick a pixel anywhere until it's at the maximum at 128 pixels of the current one in any direction.
Hence, if your displace map is a dull medium gray ( @ 127 ), it'll have no effect. But if it's a shade of green @ 193 and red @ 31, then pixels will be picked 193 - 127 = 66 pixels below, and 31 - 127 = -96 pixels on the right = 96 pixel on the left, hence the picture will slide by 66 pixels to the top and 96 pixels to the right.

The term "Zoom cube" invented by warjournal is, to me, inspired by the term "Color cube" as it looks like the the face of an RGB color cube. The Zoom term does not exactly refers to a zoom but more to a bump ( inset or outset depending of the orientation of the gradients and the scales applied to the filter ) as you can clearly see in the 2nd page page of "Gradients" @ TechSlop .

Once you're familiar with the basics ( red = horizontal, green = vertical, the shift of range ) you can distort any simple shape into another one, just like that :



Finally, in the options of the Displace filter you can scale the horizontal and vertical offsets. That way you can get rid of the constraint of the range [ -127 ; 128 ] and scale it to whatever you want to pick some pixels further or closer.

Hope I didn't wrote that monster in vain ( well, at least, making the example picture was fun )

Mathieu "POÏ" HENRI

[This message has been edited by poi (edited 11-13-2003).]

Thanks guys. Much appreciated. =)

Emperor: Mainly because this seemed more general than just Power Distort, since I was also wondering about the "Tech-Slop" stuff.

warjournal: ah! that explains much. I was trying to get to the Broken China link in your Power Distort thread, but was getting 404 errors. Silly tornadoes. It's all good now. =)

poi: thanks , that DOES clear up a bunch of stuff. =)

Inmate #1372 - Because time has little to do with infinity and jelly doughnuts!