- Posts: 296
- Joined: Mon Dec 03, 2012 3:35 pm
Hi there,
I have to excuse myself upfront, I hope this kinda question is Ok in this forum also my excuse is aimed at the sort of question, because I have to make (many) comparisons to other software.
I learned Fusion some time ago (Fusion 5 it was), but went away and used Nuke a lot. Now I want to get familiar with it again. I have a hard time replicating my usual workflows in Fusion; my biggest so far is the following -
In Nuke, there's a technique which might be best known as "colour smear", "pixel spread" or something like that. What it basically does "stretching out" pixels around a given mask, I use this quite often when I have to roto out-of-focus elements. This is based on blurring rather than erode/dilate.
In Nuke, you premultiply the image with a mask that is set around the solid values you want to extrude (so not the blurred areas which have parts of the BG in them), then blur this (a lot usually), followed by an unpremultiply. By unpremultiplying it, you get the whole area of the blurred alpha as solid colour regardles is the alpha has a value of 1 or 0.00001. After that, you merge the original, un-blurred image back on top of that so you can finally use your correctly feathered/blurred roto for the out-of-focus areas to get a proper roto on top of the BG
I think here it's described much better, but I wanted to give insight what I mean: http://richardfrazer.com/tools-tutorial ... -for-nuke/
This can be used for object removal too.
However, I can not replicate that in Fusion. I googled a lot about premult+unpremult in Fusion, and while it works it has way different results then I'd expect by it; the unpremulted results have strange harsh edges and I there’s a non-solid alpha etc.
What I like about the technique is that it’s fast, unlike most effects to remove markers (such an effect could theoretically also be used for this). A simple erode/dilate around the edges and merging the original on top doesn’t really bring me the desired result.
I use this technique also for keying hair sometimes, so I’d really like to rely on it somehow in Fusion.
Is there a way, or an alternative, to achieving such an effect?
Best,
Rick
I have to excuse myself upfront, I hope this kinda question is Ok in this forum also my excuse is aimed at the sort of question, because I have to make (many) comparisons to other software.
I learned Fusion some time ago (Fusion 5 it was), but went away and used Nuke a lot. Now I want to get familiar with it again. I have a hard time replicating my usual workflows in Fusion; my biggest so far is the following -
In Nuke, there's a technique which might be best known as "colour smear", "pixel spread" or something like that. What it basically does "stretching out" pixels around a given mask, I use this quite often when I have to roto out-of-focus elements. This is based on blurring rather than erode/dilate.
In Nuke, you premultiply the image with a mask that is set around the solid values you want to extrude (so not the blurred areas which have parts of the BG in them), then blur this (a lot usually), followed by an unpremultiply. By unpremultiplying it, you get the whole area of the blurred alpha as solid colour regardles is the alpha has a value of 1 or 0.00001. After that, you merge the original, un-blurred image back on top of that so you can finally use your correctly feathered/blurred roto for the out-of-focus areas to get a proper roto on top of the BG
I think here it's described much better, but I wanted to give insight what I mean: http://richardfrazer.com/tools-tutorial ... -for-nuke/
This can be used for object removal too.
However, I can not replicate that in Fusion. I googled a lot about premult+unpremult in Fusion, and while it works it has way different results then I'd expect by it; the unpremulted results have strange harsh edges and I there’s a non-solid alpha etc.
What I like about the technique is that it’s fast, unlike most effects to remove markers (such an effect could theoretically also be used for this). A simple erode/dilate around the edges and merging the original on top doesn’t really bring me the desired result.
I use this technique also for keying hair sometimes, so I’d really like to rely on it somehow in Fusion.
Is there a way, or an alternative, to achieving such an effect?
Best,
Rick