WTC 2 Progressive Tilt

[femr2]

Simple request...

Does anyone have any visual evidence of progressive tilt of the upper block of WTC 2 during the 20 minutes prior to initiation ?

I've looked in detail at countless photographs, and have not been able to detect progressive tilt at all.

Ideally I'd like to be able to locate two images from a very similar viewpoint which show an increase in tilt angle.

Very small angular changes can be detected if the images are analysed correctly, but of course the higher the resolution of the images, the better.

I'm not asking for opinion at all, but simply photographic resources which confirm such a behaviour.

[ElMondoHummus]

Here's one pic:
http://forums.randi.org/vbimghost.php?do=displayimg&imgid=18219

... from this thread:
http://forums.randi.org/showthread.php?t=159553

ETA: Oh, wait... you said "prior to initiation". I'm sorry. This image is from the initiation itself. My fault.

[Oystein]

Simple request...

Does anyone have any visual evidence of progressive tilt of the upper block of WTC 2 during the 20 minutes prior to initiation ?

I've looked in detail at countless photographs, and have not been able to detect progressive tilt at all.

Ideally I'd like to be able to locate two images from a very similar viewpoint which show an increase in tilt angle.

Very small angular changes can be detected if the images are analysed correctly, but of course the higher the resolution of the images, the better.

I'm not asking for opinion at all, but simply photographic resources which confirm such a behaviour.

How do you know such "tilt" occurred (source), and how much tilt is there supposed to be? So we know what to look for...

(I am offering an opinion though you didn't ask for one: I don't think any tilt could have been visible without collapse immediately commencing)

[ElMondoHummus]

How do you know such "tilt" occurred (source), and how much tilt is there supposed to be? So we know what to look for...

(I am offering an opinion though you didn't ask for one: I don't think any tilt could have been visible without collapse immediately commencing)

I confess, I don't remember what the timeline was for individual events in the collapse progression itself. I, too, recalled the tilt being an artifact of the initiating failure. But I may not be recalling that accurately; I'll have to defer to those folks here better versed in that info than I am.

NCSTAR 1-6 made mention of the tilt. I'll go through it again when I get the time, but now's not a good time for me to do that.

[femr2]

How do you know such "tilt" occurred (source), and how much tilt is there supposed to be? So we know what to look for...

(I am offering an opinion though you didn't ask for one: I don't think any tilt could have been visible without collapse immediately commencing)

Progressive tilt is one of the factors suggested to confirm CC creep, so I'm trying to find it.

The scale of tilt will be slight, as if present a tilt of around 2 degrees would result in CC failure, and collapse would then ensue.

The higher the image resolution, the smaller any detectable angular change can be.

[Oystein]

Progressive tilt is one of the factors suggested to confirm CC creep, so I'm trying to find it.

The scale of tilt will be slight, as if present a tilt of around 2 degrees would result in CC failure, and collapse would then ensue.

The higher the image resolution, the smaller any detectable angular change can be.

Suggested by whom? Where?
What is CC?

[femr2]

I confess, I don't remember what the timeline was for individual events in the collapse progression itself. I, too, recalled the tilt being an artifact of the initiating failure.
Thanks. Progressive tilt was loosely associated with inward bowing, which puts the timescale roughly during the 20 minutes prior to initiation.

Even some high resolution photographs which can be confirmed as being within the right period of time would be useful, if they are from the right *side* of the tower, as I can then do the extra leg-work myself.

I've found nowt in any of the image sets I've looked at so far.

[Oystein]

Thanks. Progressive tilt was loosely associated with inward bowing, which puts the timescale roughly during the 20 minutes prior to initiation.

Even some high resolution photographs which can be confirmed as being within the right period of time would be useful, if they are from the right *side* of the tower, as I can then do the extra leg-work myself.

I've found nowt in any of the image sets I've looked at so far.

How do you know the search is worth the effort?
How did this idea get into your head?

[Bell]

Iirc there is something written about the leaning of WT2 in "102 minutes", but I'm at work right now, so can't look it up. If still relevant by then, I'll look it up tonight.

[femr2]

Suggested by whom? Where?
What is CC?

NIST. NCSTAR 1-6. Figure 8-35, 8-37, 8-45, 10.9.4, ... Will look for additional references.

CC means Core Column.

[Dave Rogers]

The scale of tilt will be slight, as if present a tilt of around 2 degrees would result in CC failure, and collapse would then ensue.

As much as 2 degrees? That's more than a two metre drop of one side relative to the other; I'd have thought perimeter column failure would occur well before that. Are you sure you've got your orders of magnitude right?

Dave

ETA: Missed your last post re definition of CC, but still I don't see how the structure could deform this much without severing half the perimeter which would most likely initiate collapse on its own.

[femr2]

As much as 2 degrees? That's more than a two metre drop of one side relative to the other; I'd have thought perimeter column failure would occur well before that. Are you sure you've got your orders of magnitude right?

Dave

ETA: Missed your last post re definition of CC, but still I don't see how the structure could deform this much without severing half the perimeter which would most likely initiate collapse on its own.

2 degrees is a max I think. Would need to dig out the sources, but pretty sure it was based on the transition point for a buckle to occur.

I accept that it could be less.

May well be that the scale is undetectable in all available imagery, but if I can find it, I will. If photos are good enough, very small angular changes can be detected (even sub-pixel) which could well be down to 10ths of degrees.

If I can find it in visual form, then it does strengthen the case for creep significantly.

[CurtC]

Based on the perimeter column bowing that I've seen pictures of, I wouldn't think that that side of the building would have dropped more than three or four inches - a column would have to bow a lot to drop the height more than that. And two or three inches would just be about 0.07 degrees of tilt.

[femr2]

Based on the perimeter column bowing that I've seen pictures of, I wouldn't think that that side of the building would have dropped more than three or four inches - a column would have to bow a lot to drop the height more than that. And two or three inches would just be about 0.07 degrees of tilt.

NIST suggested ~12inches.
3% of a 36ft column is ~13inches.

What level of bow in a CC would you suggest with that level of drop ?

[Alferd_Packer]

aren't there some indications of tilt from just after the aircraft impact?

[Bell]

aren't there some indications of tilt from just after the aircraft impact?

I think you are referring to the building swaying heavily due to the impact. I think Frank Di Martini mentioned 20 feet regarding WTC1.

[R.Mackey]

Measurement of progressive tilt prior to initiation is theoretical. NIST's models predict up to about ten inches of creep in the support columns before initiation of collapse. This translates into a fairly small angle.

There were spoken reports that the top appeared to be leaning well before collapse, just as there were for WTC 1, but I am not aware of any photography of high enough resolution to capture this clearly. Shortly before the collapse, of course, the tilt was so large that it was unmistakable.

Have to be careful here what we mean by "initiation."

[femr2]

Measurement of progressive tilt prior to initiation is theoretical. NIST's models predict up to about ten inches of creep in the support columns before initiation of collapse. This translates into a fairly small angle.

There were spoken reports that the top appeared to be leaning well before collapse, just as there were for WTC 1, but I am not aware of any photography of high enough resolution to capture this clearly. Shortly before the collapse, of course, the tilt was so large that it was unmistakable.

Have to be careful here what we mean by "initiation."

The best quality imagery you are aware of would be very handy. I doubt many/anyone has attempted to look at very small angular deformations. With decent imagery I'm confident in identifying 10th of a degree angles.

I suggest initiation in this context ranges from, what, 30s prior to the rapid tilt beginning ? It's clear from WTC 1 tracing that some tilt/movement preceeded estimated t0 initiation by a few seconds.

I'm looking really at the preceeding 20 minutes, during the period indicated for IB development.

[Dave Rogers]

Have to be careful here what we mean by "initiation."

Have to be careful, also, to define what we're measuring relative to what. Tilt doesn't measure absolute creep, it measures differential creep between the two sides of a structure. If the core experienced similar levels of creep across its entire structure, there wouldn't necessarily be a tilt at all. So, although the presence of tilt would be strong evidence for creep, its absence wouldn't be strong evidence against it.

Dave

[femr2]

Have to be careful, also, to define what we're measuring relative to what. Tilt doesn't measure absolute creep, it measures differential creep between the two sides of a structure. If the core experienced similar levels of creep across its entire structure, there wouldn't necessarily be a tilt at all. So, although the presence of tilt would be strong evidence for creep, its absence wouldn't be strong evidence against it.

Dave

Sure, though the NIST model predicts uneven creep...
http://femr2.ucoz.com/_ph/5/2/292834536.jpg

Best quality photographs available would be well handy so I can actually try and find it.

ETA: As far as I can tell, NIST used a 56 minute timing from impact to collapse. Might estimate the expected values closer to the 56 minute mark by using the earlier NIST model values and extrapolating. Image is at 43 minutes.

[Dave Rogers]

Sure, though the NIST model predicts uneven creep...

Yes, but notice the values for the perimeter columns; there's a corner-to-corner difference of about a foot. The creep of the core, presumably, would mostly have been accommodated by unloading through the hat truss, so the differential across the core won't give you the tilt. The corner-to-corner height difference gives a tilt angle of 0.2º, and you'd need to be looking due north-west or south-east for the apparent tilt to match the actual tilt. Looking square on to a face you'll see an apparent tilt angle of 0.14º; you may be able to resolve that, but it's a worryingly low value given that your best estimate threshold is tenths of degrees.

Dave

[femr2]

Yes, but notice the values for the perimeter columns; there's a corner-to-corner difference of about a foot. The creep of the core, presumably, would mostly have been accommodated by unloading through the hat truss, so the differential across the core won't give you the tilt. The corner-to-corner height difference gives a tilt angle of 0.2º, and you'd need to be looking due north-west or south-east for the apparent tilt to match the actual tilt. Looking square on to a face you'll see an apparent tilt angle of 0.14º; you may be able to resolve that, but it's a worryingly low value given that your best estimate threshold is tenths of degrees.

Dave

Can but try.

Will see if any appropriate high resolution images emerge.

[CurtC]

NIST suggested ~12inches.
3% of a 36ft column is ~13inches.

What level of bow in a CC would you suggest with that level of drop ?

Wow, 12 inches is a lot. But having one side of the building get shorter by 12 inches would still be a tilt angle of only 0.28 degrees.

Off the top of my head, if we take the distance from impact to the top of WTC2 to be 400 feet, that would be a sideways movement at the top of 24 inches.

That much would be very difficult to notice on a video, unless the video was taken from the bottom corner of a building, sighting straight up it. I don't think you could get this kind of resolution from any videos we have.

[femr2]

Wow, 12 inches is a lot. But having one side of the building get shorter by 12 inches would still be a tilt angle of only 0.28 degrees.

Off the top of my head, if we take the distance from impact to the top of WTC2 to be 400 feet, that would be a sideways movement at the top of 24 inches.

That much would be very difficult to notice on a video, unless the video was taken from the bottom corner of a building, sighting straight up it. I don't think you could get this kind of resolution from any videos we have.

Video is very unlikely to reveal such low displacements, but am hoping some decent resolution photo's will surface. A helicopter crew took some of WTC 1 that proved very useful for the purpose, so hopefully something similar for WTC 2 exists...(was a rough test image btw)

http://femr2.ucoz.com/_ph/6/2/684947397.jpg
2190x2921px/1308.0Kb (http://femr2.ucoz.com/photo/6-0-204-3)

[UNLoVedRebel]

http://i625.photobucket.com/albums/tt332/JREFImages/InwardBowing2.jpg

[Oystein]

Drawing straight lines into a photo to prove much is never a clever idea, for it always neglects the possibilitie of all sorts of optical distortions: Camera lenses almost never map straight lines in 3D to straigh lines in 2D.

Also, can we rule out that heat from the fires creates some sort of refraction?

[Bell]

Also, can we rule out that heat from the fires creates some sort of refraction?

You are now treading into Christophera land :covereyes

[femr2]

All I'm after really is high resolution photos of WTC 2 from a viewpoint similar to the one of WTC 1 that I posted, that have a known timeframe. I've looked at a lot of photos in detail, but perhaps one of you folks have some I may have missed.

If I do manage to get some new images, then I suggest critique of any methods that may be employed to determine plumbness should only begin afterwards.

If you're aware of such good quality photos, great, links would be handy. If not, nothing really to see here.

[Oystein]

You are now treading into Christophera land :covereyes

Sorry, that was before my time :D

[BasqueArch]

All I'm after really is high resolution photos of WTC 2 from a viewpoint similar to the one of WTC 1 that I posted, that have a known timeframe. I've looked at a lot of photos in detail, but perhaps one of you folks have some I may have missed.

If I do manage to get some new images, then I suggest critique of any methods that may be employed to determine plumbness should only begin afterwards.

If you're aware of such good quality photos, great, links would be handy. If not, nothing really to see here.

NIST is the best place to get these videos and photos.

http://edocket.access.gpo.gov/2009/pdf/E9-19535.pdf

Here you can see others who haved filed FOI requests. You can ask them.
http://wtc.nist.gov/FOIA/FOIArequests09_15_42_63_88.pdf

[tfk]

Femr,

I figured out exactly what's going on here.

I also figured out why I thought that there was more tilt than there really is.

And why we both misinterpreted the data.

(In an attempt at a spirit of congeniality, I'll do this without snark. As long as you reciprocate.)

It's perception. And the fact, femr, that you work with images, not with steel.

The source of the "misunderstanding" (for both of us) is the NIST report.

But NOT thru any deviousness or deception. In their attempt to clarify, they implanted a misimpression in everyone who read the report.

And "reading the report" is exactly the source of my (& yours, I suspect) misimpression that there was a lot more tilt to the towers than there really was.

I got my misimpression from here:

http://forums.randi.org/picture.php?albumid=194&pictureid=2951

"Total displacements of WTC 2 above Floor 86 at 43 min of Case D conditions (deformed shape magnified 20 times). Note the tilt toward east and south."

Fig 1.
NIST image, NCSTAR1-6D, Fig 4-90, WTC2 tilt, 43 min.tiff

I've overlaid a fine cyan line onto the original shape & a red square on the top of the 20x tilted position.

That imprinted on me, without my even noticing, the impression that there was a lot more tilt than in reality. EVEN THO I RECOGNIZED that NIST plainly states that the deflection has been magnified 20x.

They magnify the deflection, NOT to deceive anyone, but to show clearly what is impossible to see otherwise.

I've got CAD software that allows me to ACCURATELY change the 20x tilt into 1x tilt.

I'll put the details at the end, but here are the results. And they explain ALL of your "missing tilt anomalies". And why there is no missing tilt. ("Holy Szamboti, Batman!!")

Fig 2 shows the NIST image (at 50% transparency, with 20x deflection) with blue lines overlaid on the original shape & red lines overlaid on the CORRECTED 1x deflected shape. This program was not a CAD program, but it allowed me to drop the intensity of the graphic, and show the results clearly. I was not certain of the absolute accuracy of the program, so I redid the results in the CAD program, Vellum Graphite. It is exact.

http://forums.randi.org/picture.php?albumid=194&pictureid=2947

Fig 2.
NIST image (50% transparency), straight shape (blue), true (1x) deflection (red).


Below (fig. 3) is the original shape of the tower in cyan. (I've added extensions to the side walls for a specific purpose that will be obvious later.

http://forums.randi.org/picture.php?albumid=194&pictureid=2952

Original shape.
Fig 3.

Fig 4, below is the ACCURATE (1x) tilted shape, as NIST reports it at this time. I've doubled the vertical length of the tower from the image shown above. The smoke was pouring out of the mid height of these figures.

http://forums.randi.org/picture.php?albumid=194&pictureid=2949

Fig 4.
Tower 2 with NIST claimed tilt.

THE TILT IS THERE in fig 4, femr. The exact amount that NIST claims. Show it to me...

You can see exactly why the tilt is "invisible". I drew these on a high def screen computer screen. And yet, if it were not for couple of 1 pixel jogs, I'd see no difference.

Fig 5 shows both the straight (cyan) & tilted (blue) graphics superimposed. This is real scale. Show me the tilt on a video monitor.

http://forums.randi.org/picture.php?albumid=194&pictureid=2948

Fig 5.
Straight & tilted WTC2

There is no mystery here. There is no conspiracy of deception.

When you show the real deformations of stressed parts in FEA programs, frequently you can see little difference between unstressed parts and parts stressed to their limit.
___

Finally, it is evident that you're right. Before collapse initiation, WTC1 tilted very little (less than 0.5°). And WTC2 less than 1°.

But even if there is some error in NIST's statements about tilt, that isn't going to make one iota of difference to my conclusion that there were no demolition techniques of any sort. Because there is still a mountain of irrefutable evidence that there was no demolition of any sort.

What it WILL mean is that I learn that a massively damaged, burning building built in a lattice structure like the towers can deform less than - well, less than I never really considered before now. And less than I fooled myself in imprinting the image & forgetting the NIST "20x" qualifier.

It does not change the fact that the columns were stressed well beyond their plastic limits. It doesn't change the fact that they underwent a huge amount of creep. Both of these factor are clearly shown in NIST's FEA analysis & graphs.

Here is the info that was important to me. This graphic shows the creep in WTC2 at 20 minutes & 43 minutes. (43 being the same time as the tilted images above.) Note that the creep was NOT progressing linearly, but accelerating.


http://forums.randi.org/picture.php?albumid=194&pictureid=2946

Fig 6
Plastic strain & creep
Top (20 minutes). Bottom (43 minutes)
___

In essence, you stumbled on something that appeared to be a giant "GOTCHA!" to you.

And you cajoled me into looking into it with persistent, insulting badgering. And it took all of about 45 minutes to figure out what was really going on. And about an hours to draw up the graphs to show it.

There is a lesson here, femr.

You work with graphics.

You don't work with steel. Especially steel buildings.

You thought that you had caught them (& me) in "a lie". A deception. And you thought that you had us "back-peddling". That you had your exposee of NIST's perfidy.

And the end result is "you didn't understand & the professional got it right".

You'd do well to learn a global lesson from this.
(I learned this lesson the hard way over my career.)


Tom

[R.Mackey]

Good catch! And props for the frank admission.

We saw a similar bit of silliness with the WTC 7 collapse graphics in NCSTAR1-9. Those too are greatly exaggerated in scale, so naturally they look quite a bit strange, giving the collapse more of a crushing beer can look than what we saw in reality. Took quite some time for the Truthers to grasp this little detail.

[DC]

Good catch! And props for the frank admission.

We saw a similar bit of silliness with the WTC 7 collapse graphics in NCSTAR1-9. Those too are greatly exaggerated in scale, so naturally they look quite a bit strange, giving the collapse more of a crushing beer can look than what we saw in reality. Took quite some time for the Truthers to grasp this little detail.

the Collapse FEA of WTC7 in the Final report was not scaled, the displacement scale was and is 1:1.

[Oystein]

But still, it seems possible that such a tilt could be visible in photographs - provided we have 2 photos at high enough resolution and with good enough focus taken from the exact same location 20 minutes apart. If the pixel size of the tower is at least that of the wire model in the above post, then 2 pixels tilt could be made visible by superimposing the 2 photos on top of each other.


(I am not saying that lack of such photos indicates no tilt; but finding such photos could strengthen the case. I just don't think any such photos exist.)

[DC]

Good catch! And props for the frank admission.

We saw a similar bit of silliness with the WTC 7 collapse graphics in NCSTAR1-9. Those too are greatly exaggerated in scale, so naturally they look quite a bit strange, giving the collapse more of a crushing beer can look than what we saw in reality. Took quite some time for the Truthers to grasp this little detail.

Thank you for your inquiry regarding the analysis of the collapse of World Trade Center 7. In answer to your questions regarding displacement scaling, there was no displacement scaling in any of the figures shown for the ANSYS analyses (NCSTAR 1-9, Chapter 11) or the LS-DYNA analyses (NCSTAR 1-9, Chapter 12 and NCSTAR 1-9A). With respect to the large deflection (NLGEOM) this was set to to “ON” so that large deflection effects were captured by the analyses. I hope this answers your questions.



Regards,



Steve Cauffman
Deputy Chief
Materials and Construction Research Division
Building and Fire Research Laboratory
National Institute of Standards and Technology
100 Bureau Drive, Stop 8611
Gaithersburg, MD 20899-8611

displacement scaling in a total collapse simulation would be of no use at all.
Displacement scaling is used when you cannot see the displacement in normal scale. That is usually the case, but not with a total collapse or crash test FEA.

[femr2]

Tom,

Not too good at refraining from *snark*, as you put it, are you.

Yet again you're *creating* inferences.

I'm fully aware that the amount of tilt may be slight.

I'm fully aware it may be *invisible*.

I've made that clear since the earliest end of our discussion on the topic.

I've also made it clear that even if it CAN'T be found, then it still does not mean there was no creep.

I've certainly not looked at diagrams in the NIST report that clearly state 20x amplification and gotten the *wrong impression*. That would be quite, er, silly.

You really should get out of the *arguing* game for a while.

Attributing your own misinterpretation onto me, then declaring yourself a hero and you've *solved the mystery* because you've (re?)read the NIST report is a joke. You repeatedly stated Progressive Tilt was a factor which was visible for WTC 2 (originally you included WTC 1 on that, but during our discussion it became clear there is no visible progressive tilt. Note, that I was fine with that, there is no visible progressive tilt of WTC 1).

I've looked for it for WTC 2 and can't find it. And yes, I'm looking for pixel-level changes on the highest resolution photo's available. I'm not looking for big changes. Never was.

But thanks for clearing up your misunderstanding.

Perhaps there are images around of suitable resolution and viewpoint that I've not seen, and which may allow identifying such potential tilt for WTC 2.

If not, then *that's fine*. The conclusion would then be full acceptance that there is no detectable progressive tilt for either tower.


If you've got any obscure photographs, great...

[femr2]

But still, it seems possible that such a tilt could be visible in photographs - provided we have 2 photos at high enough resolution and with good enough focus taken from the exact same location 20 minutes apart. If the pixel size of the tower is at least that of the wire model in the above post, then 2 pixels tilt could be made visible by superimposing the 2 photos on top of each other.


(I am not saying that lack of such photos indicates no tilt; but finding such photos could strengthen the case. I just don't think any such photos exist.)

Fingers crossed. Even if the photo's are not from the exact same location, there's ways of solving 3D perspective issues.

I agree that finding progressive tilt would strengthen the case for core column creep.

[femr2]

Tom,

Missed this amongst your creative *conspiracy* narrative...

Before collapse initiation, WTC1 tilted very little (less than 0.5°). And WTC2 less than 1°.

Such amounts should be possible to detect.

I suggested earlier that 10th of a degree changes might be the limit, but thinking it through, much smaller scale changes should be detectable wit the right images.

The excellent quality and high resolution photographs of WTC 1 taken by the helicopter crew do not show tilt. I'll gather some resources together to confirm that. The time of each image is known, well, stated by NIST.

Will keep looking for super-duper quality imagery.

[carlitos]

Such amounts should be possible to detect.

I suggested earlier that 10th of a degree changes might be the limit, but thinking it through, much smaller scale changes should be detectable wit the right images.

The excellent quality and high resolution photographs of WTC 1 taken by the helicopter crew do not show tilt. I'll gather some resources together to confirm that. The time of each image is known, well, stated by NIST.

Will keep looking for super-duper quality imagery.
Respectfully, why?

[femr2]

Respectfully, why?

Simple really...

Was there any progressive tilt, yes or no ?

If so, how much ?

I want to use the available visual evidence to fully (or as near to as possible) confirm it one way or the other.

The NIST model predicts it, and I'm looking for it.

I'm not looking for opinion, I'm looking to actually find it, or find it's not there.

[tfk]

Tom,

Missed this amongst your creative *conspiracy* narrative...


Before collapse initiation, WTC1 tilted very little (less than 0.5°). And WTC2 less than 1°.





Such amounts should be possible to detect.

I suggested earlier that 10th of a degree changes might be the limit, but thinking it through, much smaller scale changes should be detectable wit the right images.



Are you familiar with the complete concept behind the phrase "less than"?

Tom

[femr2]

Are you familiar with the complete concept behind the phrase "less than"?

Tom

I think I can grasp the gist of that complex beastie, yes.

Am hoping to identify *plumbness* changes to sub-pixel level, so should hopefully be able to determine anything more than 0.02 degrees (assuming photos similar to those of WTC 1 above).

Are you okay with the concept of "more than" ?

I think it's safe to assume that when you state less than 0.5/1, that you mean more than 0.02, but who knows ? I think you just like an argument, even if it's with your own shadow.

So, more than 0.02 degrees ?

[tfk]

femr,


I think I can grasp the gist of that complex beastie, yes.


Excellent.


Am hoping to identify *plumbness* changes to sub-pixel level, so should hopefully be able to determine anything more than 0.02 degrees (assuming photos similar to those of WTC 1 above).


1. Easy
Perhaps you could tell us the name of, or explain (if it's original), the algorithm you're using for your sub-pixel edge technique.

2. Easy
Perhaps you could show us examples of your raw images, blown up to, say 20 - 50 pixel wide strips capturing the actual edges at several points along its vertical dimension.

3. Tougher
Perhaps you could demonstrate your sub pixel technique in operation with real WTC data.

4. Tougher yet
Perhaps you could create a standardized blind (or better, double blind) test where you can prove that your technique works with known edge angles and spatial frequencies.

Create sharp lines of a certain angle. Use a diffusion filter of various blurring radius. Then reverse the process with your technique & record filter passes vs. angular error.


Are you okay with the concept of "more than" ?


Perfectly fine.


I think it's safe to assume that when you state less than 0.5/1, that you mean more than 0.02, but who knows ?


Absolutely NOT OK.


I think you just like an argument, even if it's with your own shadow.


I win 90% of my arguments with my shadow. I OWN him.


So, more than 0.02 degrees ?


That is yours to prove.


Tom

[femr2]

Tom,

Give it a rest. Find me some super-duper quality images, and I'll try and find some tilt. I'm really not interested in engaging in yet more of your infinite desire to *prove* any technique that's not yours, done by a structural engineer who happens to be a specialist in sub-pixel (non)linear feature detection or simply done by a *twoofer* to be worthless.

If I find something of interest I'll obviously include whatever techniques were used at the time, and then you can complain as much as you like.

For a laugh, can you grasp the complete concept of the words "hoping" and "hopefully" ? The suggested 0.02 degree figure is for a >1 pixel change of the included WTC 1 image, using a rough translation into real-word distance units and viewpoint translation to determine an associated angle. Very rough. Hopefully some mondo images will turn up and I can have a bash at 'em. :)

As I said very early in this thread, I'm after images. If you haven't got any, there's nothing to see here.

[carlitos]

Simple really...

Was there any progressive tilt, yes or no ?

If so, how much ?

I want to use the available visual evidence to fully (or as near to as possible) confirm it one way or the other.

The NIST model predicts it, and I'm looking for it.

I'm not looking for opinion, I'm looking to actually find it, or find it's not there.

OK. I guess I was looking for the next level of "why" when I asked.

You want to know whether there was any progressive tilt - why?

You want to know how much - why?

You want to confirm (via video analysis) the progressive tilt - why?

Really, why? I'm not trying to be a jerk; how did you end up on this road?

[femr2]

OK. I guess I was looking for the next level of "why" when I asked.

You want to know whether there was any progressive tilt - why?

You want to know how much - why?

You want to confirm (via video analysis) the progressive tilt - why?

Really, why? I'm not trying to be a jerk; how did you end up on this road?

To *try* and find non-virtual evidence of CC creep, or not.

If I do find progressive tilt, the case for creep resulting in global failure is strengthened considerably.

If I can find it increasing from zero to a significant amount pre-initiation, even more so.

[carlitos]

To *try* and find non-virtual evidence of CC creep, or not.

If I do find progressive tilt, the case for creep resulting in global failure is strengthened considerably.

If I can find it increasing from zero to a significant amount pre-initiation, even more so.
I will defer to the engineers here as to whether your hypothesis is correct. I had thought that this was a settled issue.

Thank you for stating it explicitly; allow me to paraphrase into a sentence:

If you find progressive tilt pre-initiation in a still photograph, "the case for creep resulting in global failure is strengthened considerably."

[femr2]

I will defer to the engineers here as to whether your hypothesis is correct. I had thought that this was a settled issue.

Thank you for stating it explicitly; allow me to paraphrase into a sentence:

If you find progressive tilt pre-initiation in a still photograph, "the case for creep resulting in global failure is strengthened considerably."

Am not going to find progressive anything in a single image, now, am I ?

[R.Mackey]

I will defer to the engineers here as to whether your hypothesis is correct. I had thought that this was a settled issue.

Thank you for stating it explicitly; allow me to paraphrase into a sentence:

If you find progressive tilt pre-initiation in a still photograph, "the case for creep resulting in global failure is strengthened considerably."

Photographic evidence of this creep would strengthen the current hypothesis. However, there is really no alternative on the table, so I would consider the amount of strengthening to be minimal -- "gold plating" so to speak.

It's also fair to assume that sufficiently high resolution data does not exist to dispute the structural creep. Thus, doing this test cannot give us a negative result -- either it supports what we know, or it provides no new information. It's not a very productive test to perform.

[femr2]

I'm still after the best quality images available.

Anyone ?

[carlitos]

Fair enough, you need at least 2 images. So, do you have an alternative hypothesis to explain the building collapse, or is asking this one question your one area of interest?

[Mangoose]

I have a huge archive so I am going through them trying to find relevant images. Here is one pair; it is less than ideal because in one image the camera is zoomed much more than the other, so the resolution is quite different.

The first one here was taken at 9:04 AM (according to the EXIF, calibrated thanks to the shots later of the WTC2 collapse, which fix the time):

http://img707.imageshack.us/img707/2677/p7300429cropped.jpg

The second was taken at 9:30 AM:

http://img143.imageshack.us/img143/3634/p7300432cropped.jpg

They were both taken from the same location with the same camera.

I'll look to see if I have other or better examples.

[femr2]

I have a huge archive so I am going through them trying to find relevant images. I'll look to see if I have other or better examples.

Thank you. Much appreciated...and any more you have :)

[tfk]

femr,


1. Easy
Perhaps you could tell us the name of, or explain (if it's original), the algorithm you're using for your sub-pixel edge technique.

2. Easy
Perhaps you could show us examples of your raw images, blown up to, say 20 - 50 pixel wide strips capturing the actual edges at several points along its vertical dimension.

3. Tougher
Perhaps you could demonstrate your sub pixel technique in operation with real WTC data.

4. Tougher yet
Perhaps you could create a standardized blind (or better, double blind) test where you can prove that your technique works with known edge angles and spatial frequencies.

Create sharp lines of a certain angle. Use a diffusion filter of various blurring radius. Then reverse the process with your technique & record filter passes vs. angular error.


Tom,

Give it a rest.


I thought the above were completely reasonable suggestions and requests.


Find me some super-duper quality images, and I'll try and find some tilt.


For the 10th time, this is your project, not mine.


I'm really not interested in engaging in yet more of your infinite desire to *prove* any technique that's not yours,


Your imagination.

done by a structural engineer who happens to be a specialist in sub-pixel (non)linear feature detection


who would this be? You?


or simply done by a *twoofer* to be worthless.


The value in any work is in the work itself.

I don't deride poor work because if its author. I deride poor work because of its lack of rigor.


If I find something of interest I'll obviously include whatever techniques were used at the time, and then you can complain as much as you like.


You claim to have been working on this project for some time. And found "negative results".

You claim to be able to perform sub-pixel resolution.

I asked you to describe the technique that you claim to have ALREADY employed (by name or verbal description), and you pitch a hissy fit.

I asked you to post some extreme blow ups of the images that you say you've already examined, so that we can see what the individual pixels look like at the building's edge, and you refuse & pitch a fit.

Color me unimpressed.


The suggested 0.02 degree figure is for a >1 pixel change of the included WTC 1 image, using a rough translation into real-word distance units and viewpoint translation to determine an associated angle. Very rough.


Care to show your math?


Tom

[femr2]

If I find some tilt, I'll present it in detail. (And would probably have to shift my perspective somewhat in the process. Shock. Horror.)

Until then, nope. Not getting into a never-ending ridiculous discussion with you again Tom.

Thanks for explaining your misunderstadings earlier in this thread though.

As I've said from day one, I haven't found any progressive tilt in the available imagery.

Pretty much every post on this thread also concludes that it's very unlikely that any of the imagery will show progressive tilt at all.

Part of your initial assertion was that a) progressive tilt (visible for WTC 2), b) IB (both WTC 1 & 2) and c) engineering simulations was proof of CC creep.

I'm not saying there was no CC creep, but can't find progressive tilt and can't directly link IB to CC creep.

I'm grateful for any images that turn up, and will attempt to find said tilt, if only to prove to myself if the assertion of CC creep is correct.

If you object, that's fine.