Front Source - Beware !!

One short of Front Source that user should be aware of, is that it's calculated before the composite, not inside the composite. Here's what i mean,


Say, below here, the cyan frame is the graphic, and the bw box is the matte for you to fill in the guy.

By normal way, you can add the matte to the guy, then use the front source to shrink the guy inside the box, like below:

Now, add a axis to control the whole graphic.Say, you graphic will start with small, then zoom into the guy. Now, the problem comes, because the front source is calculated first (you shrink the picture), you are actually zooming into a small picture source (the one you shrink, not the original one), so the picture became blurred. To overcome this, instead of moving axis2, you need to move inside the Front & Matte Source (using duplicate), and leave axis2 alone.
Now, the picture is sharped because you no more zoom into a small pictures (Small Front Source).
Because the pictures resolution is low here, you won't see much different, but just look at the eyes sharpness, you will see the different.

Another way is, to do it reverse. First, size up the whole composite (cyan frame & bw matte above), then in Front Source, adjust the guy to fit in the matte. Since the image inside front source need no shrink down to fit inside the matte (cos the matte is size up instead), then we won't have the problem of blow up small picture.

well, since i'm not smoke expert, i might be wrong here, but that's how my experiment came out. Of course, like always, there's many ways to do the same thing in Smoke.

Autodesk SmokeTips & Tricks
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