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General => Terragen Discussion => Topic started by: virts on June 16, 2008, 05:17:24 PM

Title: Make holes and caves in the terrain?
Post by: virts on June 16, 2008, 05:17:24 PM
Hi all,

I'm trying to create a terrain but I need a huge amount of caves and holes in huge rocks. I'm building a huge island and it requires these caves :). But I don't find any intrument on doing that. How can i do that or what is the best way? Here's an example picture of what i need:

Thanks for your help in advance!!!
(http://static3.filefront.com/images/personal/t/tvvladimir/127827/exqhgvfdre.jpg)

Title: Re: Make holes and caves in the terrain?
Post by: rcallicotte on June 16, 2008, 09:02:02 PM
That's a good question.  I haven't seen anything like that since I've been here.  One way would be to create a textured object to do what you want to do.
Title: Re: Make holes and caves in the terrain?
Post by: neuspadrin on June 16, 2008, 10:57:48 PM
didn't someone work on doing something with the fake stone shader to fake a cave?  The two fake stones would get tilted towards each other causing a cave to be formed between.
Title: Re: Make holes and caves in the terrain?
Post by: Oshyan on June 16, 2008, 11:14:35 PM
I think using "Fake Stones" or actual 3D objects would be the best way to do this. With external 3D objects you'd have the most control, but it might be more difficult to integrate them into your environment. True "volumetric" terrain sculpting is not yet possible, but hopefully in the future as it's a very powerful and desirable feature.

- Oshyan
Title: Re: Make holes and caves in the terrain?
Post by: Seth on June 17, 2008, 01:31:15 AM
for something like the second picture, using fake stone with good displacement will be enough... a lot of tries will be needed but it's not difficult i think...
as for the first picture, using 2 or 3 heightfields is the only solution i can think about...
Title: Re: Make holes and caves in the terrain?
Post by: neon22 on June 17, 2008, 05:52:35 AM
For something like the first picture you can use the same technique I used here.
http://forums.planetside.co.uk/index.php?topic=935.msg9021 (http://forums.planetside.co.uk/index.php?topic=935.msg9021)
There is also a link to the original idea (negative heightfields) in this thread.

What it does mean is that you have to use displacements above the hole to bridge the rock back together but there are several good techniques to define layers to do this such as image maps, height above surface etc.
I used a simple method in my example.

My feature request for rotation nodes to be attached to heightfields (so they could be arbitrarily rotated) still stands - then I could have tunnels angling through hills etc as well.
Cheers...
Title: Re: Make holes and caves in the terrain?
Post by: AndyWelder on June 19, 2008, 11:26:20 AM
You could achieve something similar as in the first pic with several downsized planets grouped closely together and a slightly noisy/displaced surface attached to them. Because they're planets you can assign vegetation to them too...
Title: Re: Make holes and caves in the terrain?
Post by: Njen on June 23, 2008, 02:57:17 AM
To go procedural or not procedural...a common choice to make in these situations, and one I make especially often when using TG2.

Many times I start out trying to make scenes 100% procedural, and I just end up with huge, complicated networks, and really slow rendertimes. In all honesty, for your example, I would model a rough shape of the island (Blender is free!), tessellate it, then bring in the model into TG2, and apply all types of lovely displacements to it. It will give you the best and fastest results, and you get to have the shape you want. Plus it will be all contained in 1 object node and a few shading nodes...nice and simple.
Title: Re: Make holes and caves in the terrain?
Post by: Seth on June 24, 2008, 01:33:03 AM
Quote from: njen on June 23, 2008, 02:57:17 AM
I would model a rough shape of the island (Blender is free!), tessellate it, then bring in the model into TG2, and apply all types of lovely displacements to it. It will give you the best and fastest results, and you get to have the shape you want. Plus it will be all contained in 1 object node and a few shading nodes...nice and simple.

good advice !