[Darby Edelen]

Rendering to an 8-bit codec should not affect the appearance of your 32-bpc composition. It will clip the color values but it should preserve the look.

Are you using a working color profile in your project? Is your exposure preview set to ‘0’ in the composition?

Darby Edelen

[Darby Edelen]

The GIF format has only ON and OFF states for transparency, so the only way to end up with smooth edges is to define a Matte color for the GIF which would ideally be the same color as the background of the website.

Darby Edelen

[Darby Edelen]

I’m 99.9% sure that there is no way to do what you’re describing with expressions.

Darby Edelen

[Darby Edelen]

Right click the layer and set it to be a “Guide Layer.” The default settings do not render guide layers.

Darby Edelen

[Darby Edelen]

[Alain Lores] “This may seem like a dumb question but how can i use both of these expressions in the Color_sample layer?”

Combining them should be fairly simple. You just need to store the result of the first code in a variable and then pass it to the second part of the expression:


factor = 5;
s = thisComp.layer("G").position.speed/factor;
[10, 720 - s];


I can’t view your video at work, so I’ve probably got your last line wrong, but hopefully the above helps you make better sense of it.

Also be aware that the sampleImage() function is incompatible with the “Render Multiple Frames Simultaneously” feature. If you find that this feature speeds your rendering then you should bake any expressions that include the sampleImage() function into keyframes before your final render.

To do this, select the property with the sampleImage() expression and use the Animation > Keyframe Assistant > Convert Expression To Keyframes menu option. This will disable the expression and create a keyframe at every frame. If you need to make changes that will affect the sampleImage() expression then you’ll need to re-enable the expression. You may also need to delete the keyframes.

Darby Edelen

[Darby Edelen]

OpenGL will down-res everything to fit into texture memory. Especially a problem for continuously rasterized or large layers. Never ever use OpenGL for final render and almost never for preview.

Darby Edelen

[Darby Edelen]

Try this:


t = Math.floor(timeToFrames(time) / 5);
seedRandom(t + index, true);
random(12);


In this case the seedRandom() function is ‘timeless’ so that calls to random() won’t generate new values over time, but the seed that we’re providing to seedRandom() is based on a modified frame count. When the modified frame count updates every 5 frames it should generate a new seed for the random() function. I’m also adding the index of the layer to the seed so that if you have several layers they won’t all return the same ‘random’ value.

Just checked this in CS6 and it works great, the “+ index” portion of the seed isn’t even necessary as I suppose each call to the seedRandom() function generates a different random progression (at least in CS6, I’ve left it just in case this is different in previous versions).

Darby Edelen

[Darby Edelen]

[Nuno Marques] “I just don’t know what value in Z it would take to have my object “touch” the viewport. Anyway, I’ll keep trying since so far I still haven’t gotten the effect to hit me on dead center.”

You get to decide how close is close enough. If someone were making this a practical effect then they would likely set up a glass or plastic sheet at an arbitrary distance for the object to hit. Depending on the size of the object you may want this arbitrary distance to be larger or smaller.

This relationship is easier to understand if you have a camera layer in your composition.

Darby Edelen

[Darby Edelen]

[Andy Galloway] “I’m sure there are much better ways to do this but that’s my fix.”

There may be more complicated ways that will work with more complex parenting setups, but the set up you recommended is the one I would recommend in general.

+1 🙂

Darby Edelen

[Darby Edelen]

[Alain Lores] ”
factor =5;
Math.abs(thisComp.layer(“G”).position.velocity[0])/factor;”

This is only sampling the X component of the velocity of your layer. Is that what you’re after? You probably noticed that velocity has 2 or 3 components, these correspond to the rate of change on the X and Y (and Z on a 3D layer) axes. If you want to work with a single value, and you don’t want to split the velocity into separate axes, then you probably want to use the “speed” property:


factor = 5;
thisComp.layer("G").position.speed/factor;


The Math.abs() function is not necessary for the position speed.

[Alain Lores] “1. The object that samples the colors to the left over shoots in height sampling black color. This object moves higher in height the faster the dot moves. How can i clamp the vales so that the object doesn’t go past a certain height value?”

There are a couple of ways to accomplish this. One would be to use the Math.min() function:


max = 500;
factor = 5;
s = thisComp.layer("G").position.speed/factor;
Math.min(max, s);


Math.min() will return the smaller of the two values passed to it, so whenever “s” is greater than “max” it will return “max” effectively clamping the highest value returned to “max.”

[Alain Lores] “2. Notice how the colors on the band of particles do not fade. Instead it’s solid from one color to the next. This is the result of the object moving way too quickly from fast to slow. Is there a way to control the speed in which the object moves? For example, how can the values be “smoothed” so that as the object samples the color it’s slow enough to gradient correctly on the band of particles.”

There is a smooth() function you could use that may help in this case. You’ll want to smooth() the position property of the sampler, but it may be more complicated than that depending on how you’ve set up the expressions.

Darby Edelen