Help with jagged ground.

Started by GFB, May 17, 2010, 07:09:59 PM

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GFB

Here is the project file.

dandelO

I'm having a look... This doesn't resemble the images you put in the first post.

The heightfield generate node - is it supposed to be used? Once the terrain is generated you are 188 metres beneath the surface of the terrain.

The problem with the .tgd you've uploaded is the first power fractal shader. The scales are way off. When you drop any scale in a fractal beneath, say, '0.005' you will get a blacked-out surface. I'd never go lower than this scale. Usually 0.01 is fine in a fractal shader. The scales in this .tgd will make the jaggies on your terrain, try disabling it completely.

dandelO

Here's a view with your default settings, the heightfield generated and a higher camera, so as to be above the terrain once you generate it, you'll notice the bad fractal is making the surface really blacked out:
[attachimg=#]

Here's a view, with fixed fractal scales in the problem shader from the same camera(I've disabled the water here for speed):
[attachimg=#]

Here's a view with the suspect fractal completely disabled, from the same camera POV:
[attachimg=#]

There isn't much difference between the last 2, is there? The second one is a bit more 'jaggy', yes, but generally, I think you'd get away with not using the small scaled fractal at all, especially if you're trying to reduce these jaggies. I think number 3 looks fine for general terrain shape.

Hope that's of some help for future reference, at least. :)

dandelO

#18
Generally, small scale displacements will make your terrain more spiky.

I also never use the 'fractal detail' tab, you haven't got as much control over the details it adds as you do with using normal power fractals after the heightfield.
In this case, the fractal detail isn't adding anything to your terrain but, in general, I'd disable it and follow the heightfield generate with smaller scaled power fractals, that you can control a lot better(if you do indeed generate the terrain, that is).

Here's another preview and an edited .tgd with your original settings but with better scales in the first fractal shader(I haven't clicked 'generate' in the heightfield for this preview image, I think that it isn't actually required for this scene, other than to raise your ground level, is this correct?):
[attachimg=#]

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dandelO

#19
And, sorry for hijacking the thread but, to take this a little further and with all nodes removed that really weren't affecting the scene(heightfield generate, strata, power fractals, etc.) here's something really quick that pretty much retains your original layout without all the clutter, it's not pretty but it should give you something to go on.

I've stripped the unneeded nodes, edited the water shader scales, unchecked 'cast shadows' on the lake object(so you don't have that abrupt black line where there should be transparency), added a sand-coloured layer and enabled 'smoothing' on it, and put a couple of surface layers in for colour. Also, the quick render settings are what I used, I've edited these, too, to give a better overall idea of what the scene will look like. Probably not what you intended the scene to look like yourself but, there you go...

[attachimg=#]

And: [attachimg=#]

GFB

Thanks :D, I'll be sure to look at what I did and what you changed so I can get a first hand experience of what you are talking about. Oh and I put In those other terrain modifiers (like strata) is so I could flatten out some land i didn't want. What should I have done to do that?

dandelO

I think you must mean the terrain in the distance. That's really the only visible terrain in the above edit that isn't in the original file. You can take a 'distance shader' and use it as the blend shader to the fractal terrain. Apply 'near colour'(as white) and set the distance in metres to how far you want the terrain to be applied to the scene. You can leave 'far colour' unchecked or, make it black. Terrain will now appear only where the white(near colour) is applied by the distance shader.
The distance between near and far colour is like the gradient's drop-off area so, if white is set to '10,000m' and black is set to '0', there will be a gradual decline in the terrain over 10,000m. To make a sharper cut-off, make the 'far distance' higher than '0', but not exceeding the 'near distance'. I don't know the actual distances from your file as I don't have it any more but you get the idea I hope. :)

GFB

I hope you don't mean like this because it isn't working for me. I linked it to the camera and the blend input of the fractal terrain.

dandelO

After plugging in the distance shader, did you hit the checkbox in the fracal terrain to 'blend by shader'? Some shaders don't autoswitch when you plug-in/unplug a blend shader, for some reason. The power fractal is one of those shaders.

[attachimg=#]

GFB

Yes but all of the landscape disappeared.

TheBlackHole

Increase the Near and Far Distances on the Distance Shader.
They just issued a tornado warning and said to stay away from windows. Does that mean I can't use my computer?