They can't argue against the crack, but they'll do anything to stop the arrow.
The numerous screenshots and pictures on this page (it'll take over two minutes at 56k) have been created from a TV quality widescreen VCD of the film. I have also made a DivX vidcap of the scene under contention (which includes both the piercing arrow and the bouncing arrow (the only one visible in the VHS version)), available via the link icon:
(200kb DivX .avi, half-speed)
Some have disputed the visual evidence of the troop being hit by an arrow in the rear "backpack". Instead, they claim that he was hit in the black bodysuit area. This claim is based on consciously ignoring the visual evidence provided, in favor of claiming that because someone screams concurrent to the arrow impact, that the troop was injured and therefore had to have been pierced by the arrow, which supposedly could not occur if the backpack were pierced. However, this claim is a non sequitur in several respects. Most notably, there's the issue of arrow length. Naturally, the arrows of a severely pre-industrial civilization are not all of equal length, but let's try to take a look at the closest shot of an arrow anyway, and compare that with the struck trooper.
For the most part, Ewoks are 3.5-4 feet tall. The arrow is around half that. Scaled to the trooper, the arrow section we see is in the range of a foot long, suggesting that there's probably enough to have directly hit his flesh.
"You measured the Ewok and arrow wrong!", they have claimed, even after I explained that those were parallel lines, not to be measured sideways. And so, behold:
In the above image, there are three red pointers. The top-most pointer points to the top of the bow. The middle/left pointer points toward the arrowhead. The lower red pointer marks the end of the straight line of the arrow. Beyond that point, no arrow is visible.
You also see a red line, and some green lines. The red line once again runs parallel to the arrow. The green line marks the termination points of both the arrow and the red parallel line next to it. And now, note the yellow lines. That's the bowstring. See how it just so happens to fit right about where I drew the parallel line to? Amazing!
A couple of Warsies refused to accept the fact that the arrow did not slice through the white backpack, still claiming that it was above the backpack due to a conveniently-angled mark on the armor in the most popular Warsie screencap from the scene, replicated on my page. As I pointed out, and as they ignored, the scene a few frames prior looked altogether different.
(70kb DivX vidcap (slow motion))
Why, look at that. One Warsie described it as looking like "a musical note". Now, look at the two original frames again.
Note the angle change of the trooper . . . note the fact that the same mark is in the same place on his backpack, but it's simply at a more Warsie-convenient angle in the lower image that they prefer to use, as opposed to the one we looked at above. Now you see why they insist on using that other frame. Not very honest of them, is it?
A couple of Warsies claimed that there was an arrow which bounced off one of the troopers, and evidently felt that this (A) disproved the point that an arrow pierced the back armor as seen above (as if somehow another one bouncing prevents another one from piercing), and that (B) they dared not tell me where it actually was despite my repeated entreaties, lest I find it and point out the flaws in their claim. It was only when one debater had the decency to truthfully detail what was being discussed (as opposed to make false statements about when and where on screen the event occurred (and then pretend I was being dishonest for not addressing it)), I realized with a laugh that they'd been talking about the same frames that contains the armor-piercing shot the entire time. (Whenever I watched that scene, I was paying attention to the arrow that penetrates, not the little guy on the extreme lower left in the little pic above, which one unscrupulous debater claimed to be in "the center of the screen". That's not even true in the VHS pan-and-scan version of the film.)
Despite the TV-quality VCD vidcap, the arrow hit
itself is little more than a blur, though the arrow is clearly visible for one
brief moment when it is in flight in front of an Ewok, in the first frame. The following
few frames show the event as clearly as I've managed to be able to create.
(It's easier to see where the arrow is in flight by watching the vidcap in
frame-by-frame, though, so I do suggest that you download the scene I provided
at the top of the page.) I've circled the arrow's position in the repeated
frames on the right side for clarity, since 'difficult to see, the arrow is': Note well the fact that this arrow is moving more slowly
than the one which pierces the other trooper. Note well that this arrow is also smaller, as
seen both when it is in front of the Ewok in the first image, and during and after the bounce.
And finally, note the location of the hit, which appears to be an area
featuring a junction of the armor sections
(i.e. a point which has more armor than usual anyway).
For reference, note the pictures below, an unmarked and marked version
of the scout trooper's back. The red circle marks the area which the arrow struck and bounced
off of. Unlike the direct hit and piercing of the armor seen in the other hit (approximate
location marked in blue), the smaller and slower bounce arrow with its lesser kinetic energy,
also had the misfortune of hitting at a location which had the most protection due to the
Note well the fact that this arrow is moving more slowly than the one which pierces the other trooper. Note well that this arrow is also smaller, as seen both when it is in front of the Ewok in the first image, and during and after the bounce. And finally, note the location of the hit, which appears to be an area featuring a junction of the armor sections (i.e. a point which has more armor than usual anyway).
For reference, note the pictures below, an unmarked and marked version of the scout trooper's back. The red circle marks the area which the arrow struck and bounced off of. Unlike the direct hit and piercing of the armor seen in the other hit (approximate location marked in blue), the smaller and slower bounce arrow with its lesser kinetic energy, also had the misfortune of hitting at a location which had the most protection due to the overlapping layers.
Unfortunately, there's no way to tell just how the impact occurred. One can try to make guesses based on various factors, but it will depend on the exact point of impact, the shape of the arrow head and its angle at impact, et cetera . . . and these are not known. The requirements would be that the impact and bounce event allow for the observed trajectory change, which could be roughly 30 degrees to the left (from our perspective) and perhaps between 30 and 60 degrees upward. That, of course, leaves us any number of possibilities, given the 'terrain' where the hit occurred . . .
. . . the arrow may have hit the point where the upper semi-circle of white armor meets the little extra round section's uppermost part, and bounced off of that complex corner accordingly. Alternately, it might've scored a glancing hit within the black semi-circle (not visible in the marked shot above), slid along until it hit the "bolt", and then bounced off. Or, it could've hit the "convex" corner of the over-the-shoulder armor strap and the rest of the backpack. We simply don't know, and unfortunately we don't get to see this fellow's armor to see if it is cracked, chipped, broken, or even undamaged entirely.
Whatever the case, it is obvious that Warsies cannot point to the bounce event as if it is some sort of disproof of the cracked shoulder armor or the direct arrow hit and piercing event. Those events occurred. To try to point to an unclear impact against armor by a smaller, slower arrow and proclaim the other two events as non-existent is not sane.