Re: Reorder Node Question

Re-order does just as it says, ....you can test it in the viewer by doing a key, placing a re-order after with the following aaan (n being for none so it has no alpha), then with cursor over the viewer and click through the shortcuts r,g,b,a then back to c (to return to normal colour view), you'll see that the alpha has now been copied to every RGB channel, but deleted from the alpha channel.

As for your problem, ...I don't know why things are going weird, but the first thing to note is that keylight uses the alpha channel of whatever is plugged into its garbage matte or hold out matte nodes (if you go into keylight and twirl down the 'plumbing' section you can change that, as with any matte input, to be another channel such as R,G or B if you wish). The mattechew node also works on the alpha channel, not the rgb. What this means is that you don't actually need to put a re-order in at all.

The process from the way you've said you want to tackle this would be something like (in simple form)

file in,
perform keylight to get a good edge,
copy that keylight node and branch it off the source (you now have two identical keylights off the one file-in, I'll refer to the first edge keylight as keylight(1) and the copy as keylight(2)).
You could now tweak the screenrange control on keylight(2) to make a hicon matte (i.e. hard edge black and white),
now place a keychew node in after keylight(2),
in the viewer switch to look at the alpha channel only (press A with cursor over viewer),
erode and soften matte until your happy (this doesn't need to be exact at this point),
plug output of keychew into the holdout matte of keylight(1)
View keylight(1)'s alpha, load keychews parameters and start playing around with the chew slider, you'll see the matte change to reflect the effect (i.e. if you effectively grow the matte feeding into keylight(1)'s holdout node, it will overtake the nice edge matte you have there, ...not what you want but you can see what its doing then button it off a bit so its just filling holes.

Does that make it any clearer? Bottom line is you don't need to use re-order, I often will throw them into scripts just to aid quick viewing when running round a script (I'm not having to toggle a and c all the time, one click to check is all thats needed), but really they're not doing anything usedul other than in that case, as the nodes usually use alphas (or can be told to use an RGB channel for matte input).

Goodluck,

andrew