Perspective transformation

Also I found that if you can get some interesting distortions...Almost like a bloat and punk type of effect...
This is a nice and WAY COOL snippet I will be playing with this one all day..Many ideasl..

bloated punk.ffxml

It is easy to see that many variations on the theme -- such as a road or a not-so-infinite plane -- can readily be made by masking off portions of the image right before the perspective distortion.

Scaling this output vertically will give you a great number of "different" perspectives.

With these two snippets and some additional scaling and masking you can do create almost any x-axis-rotated perspective plane.

If you want to get even fancier, you can probably add a "Any Angle Rotate" both before and after the perspective distortion step in the snippet, the first one to rotate the plane around the y-axis and the second one to rotate it around the z-axis. (Haven't tried that as yet, but at least in theory it should work -- I'll do that next).

Quite a number of 3D-landscape possibilities: Ground planes, water planes, cloud planes -- now we're talking!

Not to mention walls, floors, ceilings...

Ah this is great... I was waiting for something like that. This opens the door to a whole new range of filters.
I remember Uberfez showed some perspective thing like that, but as with most of his teasers, he never submits them . Luckily we still have you.

I'm sure uberfez would disagree, but:

ThreeDee, you're the man!

There's a mathematical reason it does, but it'd give me a headache to try and figure out exactly what it is. Nevertheless, by asking this question, you actually managed to make me figure out the formulas, which is a good thing, for I had been asking if anyone can...

The figures are related to the number of repeats in the profile gradient used to shrink down the original image. When you shrink down the image using that method, you get 2x+1 copies of the original image, where x is the number of repeats. (In the Infinite Plane snippet you have 100 repeats in the gradients, which results in 201 images in each direction.)

The reverse transformation Bias curve settings work with these formulas:

Bias = -x/(x+1)*100
Maximum = 50-50/(2x+1)

Thus, with the Infinite Plane snippet, which has 100 repeats in the gradient, you get:

Bias -99.0099, Maximum 49.7512

As to exactly why these formulas work, all I have to say is that my math coprocessor works independently from my language processor -- in other words, I probably couldn't explain it if I tried, not even to myself.

(Well, let me attempt to explain one thing: the reason the Maximum setting is approaching 50 as the number of repeats increases, is because that is the 50% gray that results in no offsetting. Thus the resultant image where after the two transformations the bottom row of pixels is the same as in the original -- and if you can follow that trail of logic, I'm amazed.)

Rgoer, one more note on the logic behind the math, if it helps, as to why it is the Bias curve that works: the Bias curve is an inverse function, while perspective is a function of the inverse square. The bias curve works in one axis, so on two axes it becomes "Bias squared" or inverse square.

ThreeDee, you should post these snippets to the library... very important stuff!

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Crapadilla wrote: ThreeDee, you should post these snippets to the library... very important stuff! Smile

+100

Really neat. Thanks for posting!

In FF3 perspective transformation is extremely simple. You just use the scale component set to 0 and feed a gradient to the percentage input. Black is view plane (0 distance), white is horizon (infinity).

Note: If you want the images to go all in the same direction, not flip around every other row, you have to enable Seamless tiling in the overrides. (Filter Editor: Filter>Overrides...).

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Morgantao wrote: After typing a slightly longer post a few hours ago, my computer crashed, so I now had to retype

I always make a copy in the notepad of the post that I am writing if it will include more than 3 lines, so while I am writing I copy in intervals to the notepad and save it, and so if anything happens and I loose the post I have already a copy of it, at least until the problem happened.

And I always for ALL the posts select all the text written and make a copy of the to the clipboard