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blur effect

Posted: 23 Oct 2015, 15:45
by furushil
Hello,

I have animated a small smoke effect and now I wanted to apply a blur to the animation.
What I would like to achieve is to have no blur at the bottom and a lot of blur at the top (see picture below).
I have tried all the blur effects in TVPaint but could not find a way to do this.
I don't even know how to achieve this by hand, because if I set a brush to "smooth" there is a certain point where it does not get any more blurry.
Does anyone know if there is a way to achieve this?
smoke.png

Re: blur effect

Posted: 23 Oct 2015, 16:09
by Elodie
Hmm, I would do this :
• duplicate structure
• FX stack : image source = layer with smoke animation
• brush spreading (using a watercolor or crayon brush) + check "result only" box + spreading zone as a V, so it would not affect the bottom.

Re: blur effect

Posted: 23 Oct 2015, 16:26
by furushil
Very interesting! I have not used this effect before.
Elodie wrote:spreading zone as a V, so it would not affect the bottom
I don't quite understand this part. I made a V shape but the bottom part is still affected.
brush spreading.png
brush spreading.png (82.85 KiB) Viewed 27360 times

Re: blur effect

Posted: 23 Oct 2015, 16:32
by meslin
You can also make a filled shape on another layer above the layer to be affected with an opacity gradient (white on top, black on the bottom), then set the layer as a stencil. Hide visibility.
Apply the FX Stack blur to the image layer (not the stencil layer) and the FX element will be screened through the stencil. With this method you can apply FX to selective regions of the image.
You may want the opacity to have some organic noise beyond a simple linear gradient, in which case you could just make a black and white painted opacity map on top of the image to be affected, setting the opacity map layer to stencil.
This technique works fine with Gaussian Blur, Brush Spreading, or any other FX.
smokeTVPP.png
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Re: blur effect

Posted: 23 Oct 2015, 16:42
by Elodie
Nice result Paul !

The "V" is nearly good, but shall not be like this (sorry, I'm on the bus right now and since I've got a Blackberry, I can't use TVPaint :p)

As you see, you have the V and you have a kind of "pacman / camember / pie" HUD under the V.
This pacman shape is the spread, so right now you are spreading the brush everywhere but the top.
It must be reduced and look like a slice and be turned upside down.

Hopefully it's clear :s

Re: blur effect

Posted: 23 Oct 2015, 17:34
by furushil
meslin wrote:You can also make a filled shape on top of the layer to be affected with an opacity gradient...
This is what I was looking for, thank you! I did not know that stencils can be combined with FX
(click on it to see the gif).
blur.gif
Now it would be interesting to combine it with brush spreading.
Elodie wrote:It must be reduced and look like a slice and be turned upside down.
I made it to a slice but then almost all the brushes disappear :?
I must be doing something wrong.
brushspreading_hud.png
I tried to use meslin's method and brush spreading on this test here (click on it to see the gif):
blur+brushspreading.gif
Very interesting. Depending on the brush I can have various results.

Re: blur effect

Posted: 23 Oct 2015, 18:07
by meslin
Furushil, you seem to have it under control! I didn't know for sure that the stencil solution would work until I tried it. I posted the .tvpp project above.
For the "too-few brush stamps" problem, decrease the dispersion. Warning: if you get down to 2 or 1, you may crash TVP. That happens pretty reliably when i use this FX on a large (1080p x 200% for camera) project. But dispersion=3 seems to be pretty safe and will increase your brush stamp density a lot.

Re: blur effect

Posted: 24 Oct 2015, 17:14
by Elodie
Nice result :D
Very interesting. Depending on the brush I can have various results.
Not only the brush, but the parameters too. Too bad it's not in the manual yet. I will give you deeper explanations on next week :)

Re: blur effect

Posted: 24 Oct 2015, 20:58
by Fabrice
yep, sorry, I will try to finish that part of the manual, as planed.

Re: blur effect

Posted: 28 Oct 2015, 16:22
by Elodie
I've recorded a short video with Quicktime. It's soundless, but I think images will speak for themselves :)

http://www.tvpaint.com/dl/forums/BrushSpreading.mov" onclick="window.open(this.href);return false;

Re: blur effect

Posted: 28 Oct 2015, 16:56
by furushil
Elodie wrote:I've recorded a short video with Quicktime.
Thank you for the video, it makes things more clear. I have to try the effect out on something else in the future.

Re: blur effect

Posted: 29 Oct 2015, 08:07
by Elodie
you're welcome :)

Re: blur effect

Posted: 02 Oct 2017, 08:47
by daninski
Morning all, I'm trying to find something in-depth about the brush spreading effect to work out if it'll be suitable for a project I'l planning out. I can't find any documentation about it that goes through everything. I'm trying to play with it but I'm getting the pin wheel, so I imagine one of my settings is unreasonable :D

Re: blur effect

Posted: 03 Oct 2017, 05:26
by Elodie
The doc is in progress :oops:

However, maybe you can send a screenshot and show the way you're working.