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Really lame and simple Q regarding mask’s and filter’s…
Hey guys,
This is a really simple question, so it shouldnt take long to answer. This is practically the first time i’ve ever even opened After Effects. I realise i should be doing tutorials, etc instead of posting questions here but its for part of a university project which is due scarily soon so i dont really have time 🙁
Ok, i have two 3D Max renders – one animation, and a grey-scale render of its Z-depth animation. I’m basically trying to ‘cheat’ to create depth of field, both the scanline and mentalray renderer’s are taking far too long to calculate it. I was planning on opening the animation in After Effects, then using the Z-depth greyscale as a mask to apply a blur which will hopefully simulate DoF. Thing is, once i opened up AE i couldnt figure out how to do this. I was assuming it’d be similar to photoshop where you would paste the greyscale image into a new channel, then use it as a selection to apply the blur on the normal image.
Could someone please take me through the process, step by step of applying a mask to a movie file, then using this mask to limit the effects of a filter?
Thanks for your time!
PS – in the z-depth grey-scale render the foreground is white (which is to stay in focus) fading out to black with distance. Will i need to invert it?
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2 Replies
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After Effects Production Bundle has a plugin-designed to do just that;
The trick is you have to render an .RLA sequence with the depth embedded in the picture, you can then use the effect 3D Channel->Depth of Field.Another way is to use the “Compound Blur” effect, it takes as the first argument a layer (choose your grayscale Z-layer), and then applies a blur from 0-maxBlurValue based on the brightness of the layer.
Black pixels get no blur, white maximum blur.If you want to “shift the focus”, you should precompose the greyscale layer and put a curve on it, something like an inverted solarize:
This will map black and white to white, and 50% grey to black, so you get a focus in the middle of your depth.
Alter the curve to fit your needthe grey-layer has to be in sync with the RGBA render in the timeline, but does not have to be visible.
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Excellent… thank you! you have saved my life, very much appreciated. Im going to be creating shifts in focus also, so cheers for the tip.
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