ArrGGhhh, How can I make clean continents coast ???

[cyphyr]

Been trying this for YEARS cant get it right must be some really basic misunderstanding on my part.
The attached file is just a simplified example but it illustrates my problem well. The blue is a sea level marker. It seems I can either get a clean coast line with no mountains at all with the blendshader left at its default (no ticks) or I can keep my mountains but have annoying rows of islands off my coast as they sink away with the continental shelf. What do I have to do to get a clean coast line and mountains within its area? cant seem to be done.
Suggestion please
thanks
richard

[nvseal]

Not looking at the file and testing it myself there are three ways which I would try.

1) Take the shader controlling the large continent shapes and make a copy of it. Change the colors to black and white and then tweak (notice the roughness and contrast) it so that it essentially covers the landmass above ground, then use it as a blend shader for the mountains. This can have some less than perfect results so you might also try adding another fractal on under this blend shader to break up some of the exact edges while adding different terrains around the coast lines.

2)Place a compute terrain node after the continent shape shader. Then control the mountain distribution with an altitude restricted distribution shader. I have my doubts at who well this will work and feel better about the direction of the 1st suggestion. Either way though the key is always a multi-layered blend node structure.

3)Control the distribution of the mountains so that some coast areas are flatter while other areas have mountains and or islands – so use a large power fractal as the global mountain distribution control.  Also, you can blend some mountain areas with grey blend shaders so that the mountains are not as tall as they would otherwise be. So you can get some hills in some places while avoiding the island problem in others.

Of course, the best result will probably a combination of all of these methods (or at least 1 and 3). i.e. you could have three blend shaders setup as follows. One with the least distribution is pure white, the one above it is less bright but covers more area, the last covers the most area but is the least bright. You can also control each of these blend shaders by blending them with the continent control as described in option 1.

[Zylot]

I think this can be solved quite easily with the painted shader?

[nvseal]

I think this can be solved quite easily with the painted shader?

I don't really think so. Because the scale we are dealing with (the entire planet) has such a wide range of scales and so much detail that to get a very accurate distribution would require A LOT of manual work to get something reasonable. It would of course work to a point, but I think it would just be easier to use another approach.

[buzzzzz1]

Hi Richard,

I looked at your file and noticed you used powerfactals for your landforms. Then I checked the water levels and your high water is set to 0 altitude. Then I went back to your power fractals displacement tabs and checked smooth shorelines, which are already set at 0 by default. I did a quick render and seems to work with the file you uploaded. Not sure if this is what you are after but it's all I know to do with the little knowledge I have.   

[cyphyr]

Hi nvseal

I almost posted this direct to you
Thought you might have some good pointers.

I've tried option 1 with some success and you can restrict the mountains distribution in this way BUT because this has the negative side effect of amplifying the remaining mountains displacements (both + & -) resulting in very "spiky" deformations. Useful sometimes but not as a generic mountain type. It seems there's no simple way to make a grayscale mask from TG's fractals.

I've wondered about option 2 before but haven't had any success with this, either a complete mask or nothing at all.

I think option 3 holds the best hope (with selective additions ). The issue still seems to be that the Blendshader has an amplifying effect the areas it effects. Using a Blendshader changes the shape on the mountains.  

I do wonder if a painter shader may be the way to go but I worry it might not hold up under animation. ?? Do you know if the painter shader is "bitmap" based or "vector" based?

Thanks

richard

[jo]

Hi Richard,

I do wonder if a painter shader may be the way to go but I worry it might not hold up under animation. ?? Do you know if the painter shader is "bitmap" based or "vector" based?

The painted shader is procedural. Not really vector based as such but certainly procedural.

Regards,

Jo

[cyphyr]

So dose this mean that I can paint a shader close up, mover the camera to a different place, paint again etc. and build up a more detailed mask? Do the painter shader maintain its integrity as the render camera moves in and out.

Richard

[rcallicotte]

Not to cut in, but I remember doing something with making snow drifts based upon different amounts of paint strokes here and there.  This caused build up in certain areas and left others waning, sort of like after the wind blows through the snow.

So dose this mean that I can paint a shader close up, mover the camera to a different place, paint again etc. and build up a more detailed mask? Do the painter shader maintain its integrity as the render camera moves in and out.

Richard

[jo]

Hi Richard,

So dose this mean that I can paint a shader close up, mover the camera to a different place, paint again etc. and build up a more detailed mask? Do the painter shader maintain its integrity as the render camera moves in and out.

Yes you can and it does.

Regards,

Jo

[Oshyan]

It sounds like the problem is you're either not masking subsequent detail adding displacement layers with the first one, *or* you're trying to do too much in one shader. You want to set up the basic shapes with one, low-octave power fractal shader and then use subsequent higher detail shaders with appropriate masking.

- Oshyan