Can you have an effect be "Render Only"

coming back here 5-ish years later to say: there's a workaround using Expression Controls and the Opacity property for any layers you want to hide until rendering. it still requires a manual toggle before you render, and it eats up the layers' opacity expression availability, but it at least it's faster than unhiding every single layer.

• at the top of your comp, create a blank layer (called "PrepForRender") with a Checkbox Control).
• then, for all of the layers you want to hide until render, write an expression for them that says: 

// if the PrepForRender checkbox is checked...
if (thisComp.layer(“PrepForRender”).effect(“Checkbox Control”)(“Checkbox”) > 0) 

   {100}        // ...then make the layer visible...

   else {0}     // ...otherwise, hide the layer.

• then anytime you're about to start rendering, go to the PrepForRender layer and just check the box.
• if you want a reminder, make the PrepForRender layer a text layer that says "Not Ready For Render" along the top, and have its visibility reversed based on the checkbox:

if (thisComp.layer(“PrepForRender”).effect(“Checkbox Control”)(“Checkbox”) > 0) 
   {0}
   else {100}

They should really make this an option, it would be very helpful...

Example for me: I do music videos with hundreds of green screen shots comped together, I normally need to apply Denoiser III (red giant) and Key Cleaner to all shots which are CPU/GPU heavy effects that I don't need to view after setting up. It's a PITA to have to toggle all on in each comp, it would be great to have it render only.

DEVS PLS DO THIS!

Turning of an effect in AE equates disabling a node in Nuke. so there you have it. Not much more than that with the only real trick in Nuke being its render scripts and overrides, which AE does not offer.

Mylenium

You can't do that with an expression. The easiest thing to do is to turn off the effect in the Effects Control Panel or the Timeline, then turn it back on when rendering.