changing opacity of a pre-compose

[justme2018]

Dear people,

There's a question and I hope someone got the awnser.
There's a illustration project with more than one layer, so we made a precompose. We want to change the opacity of this precompose for a nice fade-out BUT when we do this, one of the layers is visible through the other ones. We thought it should be allright since it's a precompose so all the layers should fade out at the same timing? I mean there are many project where you don't want something like this to happen.

I do understand that changing the opacity of elements even though it is a precompose means that all the elements get clearer and you see through them. BUT how can you change the opacity of more then one layers without being able to see some layers through the other ones?

[Dave_LaRonde]

Are you using any expressions?  Is anything animated in the pre comp?

[Mike_Abbott]

As Dave suggests there maybe something in the pre-comp causing this - but as a cheap work around...

If you just want to fade out... could you add a solid layer on top of your pre-comp - of whatever colour you want for your fade out - and fade that in - over the top.

[P.M.B · Accepted solution]

It's because you have continuous rasterization enabled for the pre-comp layer.  Turn it off and you will be able fade it as a single layer.

[defaultj381phg30oxk]

Thank you

[Roei Tzoref]

Paul is correct. turn off the sunburst switch for the precomp. When you precomp layers you are rasterizing them aka merging them as if you rendered them to a video and imported back. This behavior changes when you press the sunburst switch aka collapse transformation.

[Rick Gerard]

If you need Collapse Transformations turned on all you have to do is add the Transform effect to your Pre-comp. That will fix the render order problem.

When you Collapse transformations you are asking the software to process everything in the nested layer, your Pre-comp, after the transformation properties are applied so your opacity fade can make things look really weird, especially if you have some continuously rasterized layers mixed in with rasterized layers.

The render order of a nested comp happens like this when collapse transformations is turned off:

1. Render everything inside the nested comp layer
2. Render the transformations (position, scale, rotation, opacity) applied to the layer
3. Render the effects
4. Go to the next layer

When you turn on Collapse Transformations this happens.

1. Look at the nested comp and find position, rotation, scale, opacity and remember what they are
2. Check the main comp for a camera  and if there is make sure the position, scale and rotation of the nested comp are seen by the camera
3. Render the effects applied in the nested comp
4. Generally, ignore any transformation information that comes from this layer
5. Render the effects applied to the nested layer (this layer)
6. Move to the next layer.

I hope that makes sense.

Continuously Rasterize, which can be applied to vector layers and is automatically applied to text and shape layers says look at the transformations first and generate the pixels from that information before you do anything else. That is why you can scale a CR layer as much as you want and it will not lose quality. The process of turning the vectors into pixels happens after the layer is scaled, not before.

When you apply the transform effect opacity becomes an effect and it is applied after everything else is rendered solving your problem and maintaining the advantages you get with CR and CT.

Hope this helps.

[Roei Tzoref]

good information here.

Actually, any effect you apply to a CT precomp will force a composite and rasterization before any effect or mask or layer style is applied (not transform - so that's the good news). so really you can apply any effect you want to the precomp (even if no parameters are altered, even if the effect switch is turned off!) and still use the regular opacity transform and no overlap will occur.

[mikevarouhas]

I've discovered a workaround for this. If you put a solid color layer over the pre-comp that you want to fade and put an Alpha Matte on the pre-comp, you can change the opacity even with continuously rasterize selected and you won't be able to see the individual layers.