What are some good methods to help blend Mask edges?

Started by TheBadger, November 09, 2014, 02:29:41 am

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November 09, 2014, 02:29:41 am Last Edit: November 10, 2014, 07:20:22 pm by TheBadger

I would like to hear some ideas about blending the edges of masks in TG.

1) SSS
For example, I have had some problems with SimpShapes. Where I get good results with the SimpShap, but for the borders of the sss. This is more of a problem when the underlying terrain has big displacement and the sss is meant to smooth or flatten. In that case I can easily end up with very sharp steep cuts in my terrain forming vertical walls where the edge of the sss is.

In the case of the sss, I know I can get rid of the walls that the edge forms by adjusting sliders, but those adjustments effect everything in the sss, not just the edges.
Any ideas about how to better blend the area of the edges of a sss with the rest of a scene more effectively, something other than the sss sliders alone?

2) Image Map.
In the case of what I am doing today, I am making an image map in PS.
I would like it very much if someone could give me tips on how to paint the edges of my map in PS so it will come in to TG with a nicer and smoother ability to blend into the surrounding terrain
(for example, I was thinking I could paint a neutral grey around the inside of my map (if white and black are -&+ displacement, than no displacement would be...?). In this way would the edges blend better?

If so, then what is neutral grey (RGB CMYK values) in TG?

To give you a better idea of this problem, I am making a river valley in PS. The area is basically very flat. But when I bring it into TG I will want to add TG terrain along where my map edges are. How do you recommend I make sure that the edges will blend very nicely? How do I create some kind of buffer zone/fuzzy zone around my map?

I am doing my Iceland image in a sort of modular way. In one file I am working on my river, in another Some hills and in another some mountains. Then I want to make my own clips and bring them together in my final. And I have just had problems blending terrain masks in the past, so I thought I should ask for help in the start.

Hope I make sense!
It has been eaten.


1: try the use of a bias scalar (blue) and a constant of between 0.2-0.9.
2: keep the edges black and make different maps for up displacement or down displacement. Use grey tiff, or the channels in an RGB files, split again in TG. The image map shader also has an inbuilt masked edge.

Hope this helps.

j meyer

And the colour adjust node can be useful in conjunction
with image maps,too.
Assuming that you want terrain close to what you have drawn
and not close to the borders of your map,cause that would be
pretty square most likely.


Thanks guys. I will try to use the nodes you mention.

But I have confused my self on something. Is Black neutral in an image map, or is it negative? If it is neutral than that makes sense why Ulco said to make a separate maps for black. And then grey to white should be one map. Right?
Not sure why I am letting my self get twisted up here >:(
It has been eaten.


You speak in riddles... why make a map black? Black does nothing in principle (except masking out stuff). You need to start on a black canvas and draw your map in greys-white, but don't touch the edges, so it will blend smoothly in. If you need a river in a hilly terrain, paint the river in another layer over the black-white hill mask layer, and use white for the river. Displace the first up, the latter down. That's all there's to it.


Black = 0 = nothing. Black is treated differently depending on what you're doing, e.g. displacement vs. masking, but the root idea is the same: black is the baseline, it is "nothing", no effect, no change. So in the case of displacement, white = "full displacement" (if your amplitude is 1, then your surface will displace 1 meter where there is white) and black = "no displacement". In the case of masking, white = "show masked shader here" and black = "don't show masked shader here".

Make sense?

- Oshyan


Yes and thanks.
Strange what I remember clearly and what gets confused.
It has been eaten.