Second terrain...

Started by choronr, September 23, 2008, 10:29:29 pm

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choronr

Some months ago, I read here about the process and work flow of adding a second terrain to an existing one. However, I cannot find it. Can anyone help here?

Oshyan

In what way do you want to "add" the 2nd terrain? You can use the Merge shader for many of these types of processes. A search on that term ought to find some examples. BigBen in particular has done a lot of experimentation on this. His purpose is to combine high resolution localized terrain with lower resolution terrain over a larger area, so you get the benefit of high detail up close where it matters, and you also maintain the background in long-distance shots. It's definitely a useful technique for all mountain peaks with long views.

- Oshyan

choronr

Thanks for getting back Oshyan. Iwanted to start with a procedural terrain (low altitude); then add a DEM terrain (higher altitude) file off in the distance. If you have the process and work flow on this, I would appreciate it. Also, I will check out Big Ben's threads on this.

Bob

choronr

Oshyan, I tried the search for add 2nd terrain and BigBen but don't find a lead to the info.

bigben

September 27, 2008, 12:13:41 am #4 Last Edit: September 27, 2008, 12:42:40 am by bigben
Got your PM.  The last post gave us a better idea of what you are trying to do, so here is one way...

Here is a link to my main discussion on tiled terrains.
http://forums.planetside.co.uk/index.php?topic=2036.0

The main problem you're going to have is disguising the border between the two terrains since the elevations will be markedly different.  Given that the border will be in the distance it should be relatively easy to disguise it by a) hiding the border behind some hills closer to the camera or b) creating a broad blending shader between the two.

I've attached a quick example using my terrain blending mask... the mask was ready made.  It combines a TER file of Glacier National Park with a fractal terrain (displacement of 500).  I've cropped the 8194 terrain by 50% with a broad blend. Rather than merge the terrains I just use the mask as a blending shader on both (inverting the shader for the fractal terrain)  The end result, a fractal hill with DEM derived peaks in the distance.

You may need to make a more appropriate mask for what you are trying to do but the principle is the same.

choronr

Ben, thank you so much. I'll be absorbing this and get back to you with some results hopefully.

bigben

You're welcome. Here's a demo render with the fractal displacement dropped to 200 and a yellow surface added to show the distribution of the masked fractal terrain.

choronr

Thanks, this shows a clear definition of each. Attached is a .tgd that, with the help of buzzzzz, was able to add a distant terrain; however, I've tried to do another but could understand how to get there.

bigben

This TGD is different to mine in that it simply adds the fractal terrain to the TER file.  The disadvantage to this is that a) you will still get some noticeable discrepancies in altitude at the edge of the TER, even with border blending set to 0.1 (although you could increase this number if it was a problem) and b) the TER will have the fractal displacements added to it (in this case everything will be covered with dunes)

The most practical/simple solution in your case may be to make an image map for a mask based on your TER to define which bits you want/don't want. Blur it a reasonable amount, and don't be too scared to make it low resolution (TG's antialiasing will smooth things out nicely and save you a lot of RAM).  Then use this image as a mask for your terrains.  You may need an extra node to set a mask to your dunes.

If you still have TG0.9 running, it might also be more useful to adjust the height range of the TER before loading it into TG2. (http://forums.planetside.co.uk/index.php?topic=4840.msg50533#msg50533)  This should save you some extra RAM for your plants.

choronr

Thanks again BB for all your good information. I will continue to experiment with it until I come up with something that is workable. In the meantime, I've posted an image in Image Sharing using the terrain and secondary terrain that buzzzzz had helped me with some months ago. I tried replicating that process but failed to figure it out.