[Darby Edelen]

[Todd George] “I am wondering if I will have trouble trying to install software that has to upgrade from one chip set to another”

I would remind you that you can install PPC OS X applications on your (hypothetical) Mac Pro via Rosetta and then upgrade them to the Universal Binary as long as this is an option from the vendor =)

[Darby Edelen]

Alright, I didn’t see the specific angle values in your post and went a little expression crazy.

So this expression would be applied to the Opacity value of a ‘blip’ layer (a single dot whose anchor point is at the dot’s center) and would reference the rotation value of the ‘niddle’ layer (called ‘Radar Line’ in my expression). It takes the position of the dot layer and converts this into an angle based on the center of the Radar Line layer, then compares this angle to the angle of rotation of the Radar Line layer… It does not fade the dot out after a certain number of frames, but instead after the Radar Line has gone a certain number of degrees. So a faster moving line (‘niddle’) would need a higher fadeAngle value. Here’s the nitty-gritty (Replace layer(“RadarLine”) with layer(“[your-layer-name-here]”):

fadeAngle = 90; //Distance in degrees from the line before the dot is transparent
maxOpacity = 100; //The maximum opacity of the dot
minOpacity = 0; //The minimum opacity of the dot
center = thisComp.layer(“RadarLine”).transform.anchorPoint; //Center of the line’s rotation
x = center[0] – transform.position[0]; //Difference in X value between the Center and our dot
y = center[1] – transform.position[1]; //Difference in Y value between the Center and our dot
rev = 0; //Boolean to control ‘reversal’ of the result of the atan function

//The following statements and declarations convert the 0-90 degree results from atan into full 360 degree results
if((x <= 0)&&(y <= 0)){ rev = 1; v = 90; } if((x <= 0)&&(y >= 0)){
v = 270;
}
if((x > 0)&&(y > 0)){
rev = 1;
v = 270;
}
if((x > 0)&&(y < 0)){ v = 90; } //Use the absolute values of our X and Y differences x = Math.abs(x); y = Math.abs(y); if(!rev) t = 360 - (radiansToDegrees(Math.atan(y/x)) + v); //If we don't want to reverse our atan results then use this declaration else t = radiansToDegrees(Math.atan(y/x)) + v; //Otherwise use this one if(thisComp.layer("RadarLine").transform.rotation > 0) r = thisComp.layer(“RadarLine”).transform.rotation % 360; //If we’re in positive rotations use this declaration
else r = 360 – (Math.abs(thisComp.layer(“RadarLine”).transform.rotation % 360)); //Otherwise use this one
o = 0; //Opacity defaults to zero

if(t > r){ //Only make our dot visible if the line has passed us travelling in acounter-clockwise direction
//Change the > to a < if your line is moving in a clockwise direction d = t - r; //Difference in angle between the line and our dot o = linear(d, 0, fadeAngle, maxOpacity, minOpacity); //set the opacity based on this difference }; o; //return the opacity I uploaded a movie of this expression in action here: https://video.google.com/videoplay?docid=-6657224198412944055

The nice thing about this expression is that even if you animate the position of the dot layer it will still appear correctly. Note that this expression doesn’t take into account the blip’s distance from the center of the radar line (which could be done with a fairly easy vector length check, let me know if this is a desired feature). The blip will appear no matter how far away it is from the center as long as the line’s angle is close to its own.

[Darby Edelen]

[jimmybee500] “64bit”

lol, I read that and thought for a half a second you were asking for 64bpc =O Then my brain started working again.

[Darby Edelen]

[Steve Roberts] ”
O means you’re not purging at all. If more than your available RAM is required to render a comp, you will crash when set to 0.”

I don’t believe this is necessarily true. 0 is the default setting. At this setting I’m almost positive that AE purges RAM as is required during a render to keep the RAM Cache below your maximum setting (Default is 60% I believe).

[Darby Edelen]

Just to be clear, what are you trying to un-premultiply in this case? Something without an alpha channel?

[Darby Edelen]

[bdstric] “I attempted scaling and precomposing and the same problem exists. The bottom edge of the curtain remains static. Any other ideas?”

Nope, but I still have the same idea =)

You go the order wrong there, pre-comp and then scale inside that pre-comp… The goal is to make a layer (a pre-comp) that has your curtain solid in it but with a buffer of at least 20 pixels of transparency surrounding it. So if your curtain layer is 720×480 and your displacement is 720×480, pre-comp your curtain layer into a 720×480 composition then scale it down so that the curtain layer is about 700×460 inside a 720×480 comp. Then the displacement map will displace the entire 720×480 pre-comp. You’ll still have ‘hard edges’ but those ‘hard edges’ will be on the transparent pixels at the border of the 720×480 pre-comp (so you won’t see any hard edges).

Note that the 20 pixel buffer I mention here is pretty arbitrary, it really depends on your maximum displacement values in the displacement map effect. A 20 pixel buffer would work for a maximum displacement of up to 20.

[Darby Edelen]

[rendernyc] “being a freelancer, i can take expressions and scripts with me…”

Well now we’re getting way off track, but plug-ins are very easy to… plug… in… on other peoples’ computers, you’d just better make sure you remove it when you’re done to avoid license issues =O

[Darby Edelen]

If you pre-compose the curtain and make sure that there is transparent space around the curtain layer (easiest way might be scale it down 5%) in the pre-comp the displacement map should displace the ‘edges’ of the curtain.

[Darby Edelen]

Also if you’re using motion blur make sure you don’t make your purge setting too low, AE uses previous (cached) frames to generate the motion blur.

[Darby Edelen]

[Ramin Bahari] “I thought one can only use the above layer as t-matt ?”

If the layer you want to use as a track matte is below the layer to be matted, you can duplicate the layer you want to use, put it above the layer you want to matte and parent it to the original (lower) layer.