Nalands Building Terrain

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Nalands Building Terrain

Post by Nalates » Mon Apr 12, 2010 7:31 am

OpenSim Terrain
If you are reading the Devokan Blog you have seen the hint about retrieving an old D’ni building. I decided I could devote a new region to the idea. Of course the first thing to do is handle terrain.

There are tools built into the viewer for manually creating terrain. It is also possible to draw ‘height’ maps for use with OpenSim and import them. Some people even sell pre-made terrains. For those wanting to create a height-map based terrain there are lots of OpenSim Terrain Tutorials and Resources. One can even use Bryce to create OpenSim terrain.

For those that aren’t sure exactly what they want for their terrain the tools built into the console of the OpenSim server and the tools in the client viewer allow one to make a free form terrain on the fly without much knowledge or experience. While there is not much technical complication getting a good terrain takes some artistic skill. I’m still working to fix my first terrain. I think I’m doing better on the new ones I start from scratch.

Default OpenSim Terrain

Initial Terrain
When one sets up a new region they get a default terrain. In OpenSim it is a Goose Egg in the middle of the sim and a rough sea floor. This pretty much means one needs to touch every square meter of the place. This is where the console commands give one a big hand.

Code: Select all

 === terrain ===
* terrain load - Loads a terrain from a specified file.
* terrain load-tile - Loads a terrain from a section of a larger file.
* terrain save - Saves the current heightmap to a specified file.
* terrain fill - Fills the current heightmap with a specified value.
* terrain elevate - Raises the current heightmap by the specified amount.
* terrain lower - Lowers the current heightmap by the specified amount.
* terrain multiply - Multiplies the heightmap by the value specified.
* terrain bake - Saves the current terrain into the regions revert map.
* terrain revert - Loads the revert map terrain into the regions heightmap.
* terrain newbrushes - Enables experimental brushes which replace the standard terrain brushes. WARNING: This is a debug setting and may be removed at any time.
* terrain stats - Shows some information about the regions heightmap for debugging purposes.
* terrain effect - Runs a specified plugin effect
* terrain flip - Flips the current terrain about the X or Y axis
* terrain rescale - Rescales the current terrain to fit between the given min and max heights
If you have existing terrain you want to keep, realize some of these commands will obliterate it. Others will work with it. Also, the tools are not perfect. When you are working around the edges next to existing terrain in another region, they will from time to time reach across and change it. Backup your surrounding terrain before starting (Terrain save [filename].raw).

The ‘terrain save’ command will save a height-map (raw file – other types are possible). That map can then be edited in other programs. So, one can save and add to their terrain in various ways. That is another tutorial.


The ‘terrain fill’ command will give you a flat plain. If you want the deepest SIM possible type ‘terrain fill 0’ at the SIM console and press enter. This is a nice way to start a terrain design.

In this image I have set the water to very clear so we can see the new ocean floor... nice and flat.

Standing on the new flat ocean floor.

I have trouble getting what I visualize in my mind to fit the ground. So, I like being in SIM and seeing how things fit. To do that I created the ‘North Restoration’ region (which got moved to the south… time for some IC thinking) with a flat ocean floor. I set the elevation to match the other Devokan SIM’s. Then I put in my foundation, in this case a 150m diameter disc.

The single control panel for terrain modeling in-world.

Then I use the RAISE tool to get a chunk of the floor up where I want it. None of these tools are precise. One can place a prim at a specific elevation to get close. Precise terrain can be built in Blender or other tools.

To start editing terrain just right click on the ground. Select Edit Terrain. The Build Dialog opens(Above) with the Terrain tab selected. It initially is asking one to select the ‘parcel’ one wants to work with. When you own the whole region it is only needed if you want to protect some part already built. Generally you can ignore selecting. However, notice that you can select an area an apply raise, or any other tool, to the entire selected area, which can be handy.

Pick RAISE and set the size of the tool. It is somewhat like brush tools in Photoshop or GIMP. THe strongest force is in the ceter of the tool. All the white arrows show you the size of the tool and 'which' tool is selected.

Next we can select the strength of the tool, the stronger setting raise terrain faster and farther.

Raise tool in use.

The result of the RAISE tool is deliberately irregular. So, if you are working toward smooth rolling terrain it leaves something to be desired. Also, if one has a need to have some well defined vertical walls, like inside a basement (we commonly build below water level in SL & OS) it is not that helpful.

Raise Tool Result

Now that I have something above the waterline, I switch over to the FLATTEN tool. This tool pulls surrounding terrain to the same elevation as the point you click on. As you move the tool about you find it is really quick. This makes it handy for drawing areas and setting target plains. Then one can come back fill in and round off.

Result of the FLATTEN Tool

In the image you can see I have created two plains. Using the SMOOTH tool I can make these more natural looking. The nice vertical walls are nice when you need a basement wall.

Once you have a bunch of work done, save it. If for any reason the SIM crashes, your work will be lost. Probably not all of it. OpenSim is saving changes to the database as you go. However if the crash trashes the database (and this is Alpha software) your work is gone. Use the Terrain Save command often. Remember. It is a SIM console command, not a viewer thing.

Building terrain in SL and OS is a matter of pushing terrain around until you have something you like. It is also worth noting that the tools work slightly different in each viewer. I personally like the way the Hippo viewer works terrain.

Terrain Cover
The terrain is covered by 4 sets of 4 textures. Each quadrant of a SIM has a texture set. They can be different textures. Since the SIM is 256m x 256m this means each set of textures covers 128m square. The textures are blended by elevation. Once can go into the viewer and open the Estate Tools to change the textures and the elevation they blend at.

The default textures are low resolution and small so they will load quickly. However, upping the resolution really improves the looks.

Low Rez Texture

Hi-Rez Replacement

This is a step up from 512px square image to a 1,024 px square image. While larger images can be uploaded for use in OpenSim the upload process runs them through a compression. I have no tested to find the optimum size. I’m guessing 1,024 is it.

Creating paths in grass or sand and other custom ground textures is possible but more limited than what we see in MOUL. With some thought most of the things we see in MOUL can be approximated. The serious limitation is the lack of MIPMAPS. The area OS & SL excel is in easy impromptu shaping of the terrain.
GoW, GoMa and GoA apprentice - Guildmaster GoC - SL = Nalates Urriah

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