Classic alpin

[cajomi]

This example uses the new isoline tool, selctions for the terrain shape and erosion filter and the improved thin flows erosion.
The terrain was shaded and rendered in GeoControl 2 (alpha version).

[craftycurate]

This same Alpine terrain rendered in Vue 6I (with a little postwork).

[cajomi]

For a render in Vue I would first change the size of the terrain to 4096, it looks a bit smoothed and not rich of details.

If you change the terrain size, you should enable the "Thin Flows" erosion only in the last two or three levels. Else, even with the higher resolution it get a bit oversmoothed.

[craftycurate]

For a render in Vue I would first change the size of the terrain to 4096, it looks a bit smoothed and not rich of details.

If you change the terrain size, you should enable the "Thin Flows" erosion only in the last two or three levels. Else, even with the higher resolution it get a bit oversmoothed.

Yes it is just a first attempt at lower resolution.

Also. I cannot find "Thin Flows" among the list of filters.

But in a different post, you say that procedural terrains do not need to be increased in size from 256?

[cajomi]

No wonder, that you could not find it. I had uploaded the wrong preset.
It is corrected now.

The resolution of the terrain was meant for GC, in Vue the resolution is controlled by the resolution of the tif, the grid size has only influence to the preview/OpenGL.
I work in general in GC with 1024 terrain size, and if all is like I want it, I change the size to 4096. If there are erosions, it is often better to "shift" them. This changes the final result, but mostly it looks better.

[RealUser]

Very impressive structures. Makes me really curious abot GC2.

[craftycurate]

An updated version of previous render with following improvements:

1) 4096x4096 resolution (both terrain and texture map)
2) Crisp antialiasing to retain detail.

[craftycurate]

I cannot find the corrected preset - the post in "How To" no longer includes a gts file.

[cajomi]

Now it is there. Do not know, why the attachment did not work.

[monks]

Love the renders! :) The flow and colouring are very convincing.

monks

[Kathye]

The resolution of the terrain was meant for GC, in Vue the resolution is controlled by the resolution of the tif, the grid size has only influence to the preview/OpenGL.
I work in general in GC with 1024 terrain size, and if all is like I want it, I change the size to 4096. If there are erosions, it is often better to "shift" them. This changes the final result, but mostly it looks better.


For Bryce I also like to work with 4096 rather than 1024. I was curious after reading this message to try this preset upscaled. It works beautifully at 1024 within the obvious limitations of that mesh size. But increasing the size to 4096 in GC does seriously upset the look of the terrain.

Please could you clarify for me what you mean by 'shift' erosions when you are increasing terrain size? This may explain most of my failure so far in that I routinely am changing from 1024 to 4096 once I have something I like and it is nearly always disappointing in result.

Kathy

[cajomi]

That means, if I had eroions from Level 256 to 1024 in the small terrain, I disable the levels 256 and 512 for the big one, so that I have erosions only in the last three levels.

Another possbility is to disable only the erosion between, if there are three. So for example try it with erosions in every second level - 256, 1024 and 4096.
Also, if you want to keep the look, you should reduce the noise and the filter value in the levels above 1024.

For Bryce you should export the pgm with 4096 resolution.

[monks]

This is how I understand it- maybe Johannes can clarify this. If you're increasing the resolution of the terrain (as opposed to the size) then it will make a difference. GC dynamic levels (noise and erosion) operate as octaves. Octaves are ratios of the whole. (think waveforms because the terminology used in both acoustics and terrain noise synthesis is the same).
Each dynamic level in GC is half the frequency of the previous. So dynamic level 4 will create noise at half the frequency of level 2 -that is, noise with larger scale undulations. So, if you have any level set in GC, if you double the res of the terrain, then you should double the level *if* you don't want to add any more relative detail that's already there.
I *think* that's right...:)

monks

[Kathye]

Still experimenting... not there yet.

Here's another of those questions that will give away just how poor my understanding is I expect.

The classic alpine gts has inputs at all the levels above 1024 even though it is optimised for a 1024 terrain. So what exactly DOES happen with the calculations of a 1024 terrain if you change the levels higher than 1024?

This is really the biggest struggle for me at the moment. I have been wandering around the last two days thinking through the whole dynamic level thing hoping the fog will clear and so far I'm still not getting it. I thought if I worked hard in GC just altering settings it would come to me. I've got reasonably conversant with Bryce's DTE on the same basis and everyone tells me that's REALLY hard to understand ;)

I'll keep plugging away, something will click eventually. I'll ponder on octaves for a while, that might help.

Kathy

[monks]

Actually, I've got the above incorrect. I said:
'Each dynamic level in GC is half the frequency of the previous. So dynamic level 4 will create noise at half the frequency of level 2'

That should read:
' Each dynamic level in GC is half the frequency of the previous.So dynamic level 3 will create noise at half the fequency of level 2.


About noise as octaves. Imagine a flat plane terrain. Run a noise through it- say a sine wave (http://cbdd.wsu.edu/kewlcontent/cdoutput/TR502/page9.htm) that has a frequency exactly the same as the width of the terrain. You would get an undulation with an up and down. So you've added a noise that is 'pitched' at a certain octave. The x axis on the sine wave applies directly as ground distance in GeoControl (or any terrain app).
Now take a second flat terrain plane and double the frequency of that sine wave and add that. Compare the two planes, and you'll see that the second has 2 undulations, or smaller scale noise if you like.

If GeoControl's noise is the sine wave, then the first example is equivalent to say level 2 The second example is equivalent to level 3.

Now imagine what the plane would look like if you applied the first noise octave, then the second one to the same plane. You would get the second quicker wave added to the first wave: superimposed on it. That's what happens when you use two adjacent levels in Geocontrol's noise, say 2 and 3, or 5 and 6.
You can then imagine what it would look like with all of the levels applied- very noisy.

monks

[cajomi]

Another try from me:

If you change the size from 1024 to 2048 following happens:
GeoControl takes the 1024 terrain and add to every exisiting point 2 new points, one in the horizontal and one in the vertical axis.
This points are at first a average between the two next points (from the 1024 terrain).
This would have a kind of smoothing effect. It would not produce more details, but simply a higher resolution.
The next step of GC is then adding details to the terrain, by discplacing the new points. The way, how new points are displaced, is determined with the filter settings.
For example, a noise with a value of 100 will add some random to the new points.
To see that, generate a terrain, noise to 0 in all levels. Now increase the noise value in the last level (the last level is always the level with the size of the terrain, all higher levels are simply ignored). If you then zoom in, you will see the effect in the terrain.

That is the principal way it works.
Now to your general problem, and it is not only your problem:
As far as you do not use erosions, and you encrease the size of the terrain, all looks like it should be, details are added, as it is expected.
If you use erosion and you want to keep the look of the smaller terrain, you run into a problem. The easiest way would be, to disable the erosion in the new last level, by setting the level control in the levell 2048 to zero. The old terrain will show after the resizing, and the general look will stay. But you will have no added erosion details.
If you want to have more fine erosion details, you get a problem. The erosion in the level 2048 is calculated on the 1024 terrain, which has always erosions and is so now different to the terrain in the level 1024 and so the erosion and flowmap also looks different. Mostly the flows are thinner and much shorter.
There is an easy way to keep the old erosion, and mostly important the old flowmap, by setting the level 2048 of the erosion to zero, and add a second erosion filter, where all levels except the 2048 level are set to zero. This will produce the same erosion, as if you had simply enabled the level 2048 in the first erosion (if the settings of the filter are all the same), but you will see, that you now can use the flowmap of the level 1024 (which is resized to 2048) and the flowmap of the erosion in the last level. So you get the same look, and most important for the look is the flowmap, but you can add details in the look with the second new flowmap. For Bryce you must then combine the both flowmaps in Photoshop or.....

[Kathye]

Ok thanks... I may be getting there, will take some more trial and error testing today and see what I come up with. Sometimes I just get this stubborn streak and that's the best thing for learning how a program ticks. Good for producing headaches but at least I usually persist till I get it.

I do think this is very important for Bryce users though. 1024 really does not work well for foreground terrains, when I did this image

http://www.pbase.com/kathye/image/69810994

last summer I had just started with GC 1 and hadn't realised what would happen when I scaled the 1024 terrain in Bryce without having first increased the size in GC. Only too late I found it very badly triangulated in the foreground and as I'd done a great deal of modification to place the lake, the diffusion layer for damp earth around the lake I just had to paint the foreground to colour out the triangles.

I was lucky with this one

http://www.pbase.com/kathye/image/71695056

using a tweaked version of one of the presets (I forget which) at 4096 and the foreground was fine.

I've no idea how many of your customers are Bryce users but it does seem to be one of the applications most able to use GeoControl terrains, I assume that means Carrara is too but I don't own that.

Bryce is also supposed to handle 16bit Tifs though my attempt to do that this week was very poor. I believe from Bryce forums that there may be a problem there so I'll hold off worrying too much about that just now. Importing .pgm is fine.

[cajomi]

That wolf image is really beautiful!!
Most customers are Terragen users, but there are also about 10 % Bryce users.
Forget about the tif for Bryce, pgm is slow but has really high qualtiy.

[Kathye]

Thank you for the compliment on the wolf image :)

And thankfully, after a day of fiddling and playing on and off, I may be getting closer to having a feel for what's going on. Thanks again for your patience in trying to get it through to me.