FAQ

What is OpenSim?
OpenSim is a platform for operating a virtual world, and supports multiple independent regions connecting to a single centralized grid. This is somewhat similar to the web, where anyone can run their own web server, tied together through the internet. It can also be used to create a private grid, analogous to a private intranet.

What is a region?
A region is what you see when you log into OpenSim. It is the physical place (well, virtual physical space) where avatars move and interact. It is a square patch of land which may contain an island, mountains, a plain, buildings, etc., or just an ocean.

What is the grid?
The grid is the level that organizes the regions and their positions in the world, and handles things that need to exist across regions, such as a user's inventory. You can think of it as similar to the world map.

What does ... mean?
See OpenSim:Technical Reference for definitions of some terms commonly used in OpenSim.

Configuring OpenSim
First, read OpenSim Configuration.

Where can I get a new UUID for my sim config?

 * See OpenSim Configuration

Can I run multiple regions with OpenSim?

 * See OpenSim Configuration

What databases can be used with OpenSim?

 * See OpenSim Configuration

Running OpenSim
===I get a bunch of ERROR: There was an error while scanning assembly:... errors on startup, but OpenSim appears to run normally. Is this a problem?=== No. These errors are being put out by the third party plugin scanning code. As we have it scanning the entire bin/ directory, it picks up dlls which don't have the correct information to be scanned, and so puts out this error. Don't worry about it :)

For the record, the current set of errors are

ERROR: There was an error while scanning assembly: /home/caseyj/jc/it/v/virtual-worlds/second-life/servers/opensim/src/opensim-svn-minim/bin/PhysX-wrapper.dll (Could not load file or assembly '/home/caseyj/jc/it/v/virtual-worlds/second-life/servers/opensim/src/opensim-svn-minim/bin/PhysX-wrapper.dll' or one of its dependencies. An attempt was made to load a program with an incorrect format.)

ERROR: There was an error while scanning assembly: /home/caseyj/jc/it/v/virtual-worlds/second-life/servers/opensim/src/opensim-svn-minim/bin/ode-debug.dll (Could not load file or assembly '/home/caseyj/jc/it/v/virtual-worlds/second-life/servers/opensim/src/opensim-svn-minim/bin/ode-debug.dll' or one of its dependencies. An attempt was made to load a program with an incorrect format.)

ERROR: There was an error while scanning assembly: /home/caseyj/jc/it/v/virtual-worlds/second-life/servers/opensim/src/opensim-svn-minim/bin/ode.dll (Could not load file or assembly '/home/caseyj/jc/it/v/virtual-worlds/second-life/servers/opensim/src/opensim-svn-minim/bin/ode.dll' or one of its dependencies. An attempt was made to load a program with an incorrect format.)

ERROR: There was an error while scanning assembly: /home/caseyj/jc/it/v/virtual-worlds/second-life/servers/opensim/src/opensim-svn-minim/bin/openjpeg-libsl.dll (Could not load file or assembly '/home/caseyj/jc/it/v/virtual-worlds/second-life/servers/opensim/src/opensim-svn-minim/bin/openjpeg-libsl.dll' or one of its dependencies. An attempt was made to load a program with an incorrect format.)

ERROR: There was an error while scanning assembly: /home/caseyj/jc/it/v/virtual-worlds/second-life/servers/opensim/src/opensim-svn-minim/bin/sqlite3.dll (Could not load file or assembly '/home/caseyj/jc/it/v/virtual-worlds/second-life/servers/opensim/src/opensim-svn-minim/bin/sqlite3.dll' or one of its dependencies. An attempt was made to load a program with an incorrect format.)

Errors about modules not found and RegionBanListItem could not be loaded
This is caused if you upgrade from trunk through svn and copy new files in the same directory. To solve these errors during the startup of opensim.exe remove the following files from your bin folder:

OpenSIm.DataStore.MSSQL.dll

OpenSIm.DataStore.MSSQL.dll.mdm

Errors from incomplete data migrations
This can happen during version upgrades if for some reason a database migration fails when there is a change in the way OpenSim stores data.

You may see errors on the OpenSim console like:

[LLOGIN SERVICE]: Exception processing login for [username]: MySql.Data.MySqlClient.MySqlException: Table 'opensim.UserAccounts' doesn't exist at MySql.Data.MySqlClient.MySqlStream.OpenPacket [0x00000] at MySql.Data.MySqlClient.NativeDriver.ReadResult (System.UInt64& affectedRows, System.Int64& lastInsertId) [0x00000] at MySql.Data.MySqlClient.MySqlDataReader.GetResultSet [0x00000] at MySql.Data.MySqlClient.MySqlDataReader.NextResult [0x00000]    at MySql.Data.MySqlClient.MySqlStream.OpenPacket  [0x00000] at MySql.Data.MySqlClient.NativeDriver.ReadResult (System.UInt64& affectedRows, System.Int64& lastInsertId) [0x00000] at MySql.Data.MySqlClient.MySqlDataReader.GetResultSet [0x00000] at MySql.Data.MySqlClient.MySqlDataReader.NextResult [0x00000]

In this case the 'users' table had not been migrated to the 'UserAccounts' table which OpenSim was expecting, also resulting in the viewerside error:

Login Failed Error generating Login Response

I solved by fixing the filesystem permissions that were causing the migration to fail (on my Linux box '/var/lib/mysql/...' had got itself messed up), then dropping the 'migration' table and running the server again (from the [non-critical] migration warnings encountered there was probably a more precise way to do this, but I was fully backed up so I did it quick-and-dirty). Other than loosing terrain data refs. and current shape/clothing/attachment data (easily restored in-sim) all was now good for me.

Are there test servers running OpenSim I can connect to?
Yes. Check out our Grid List! There are often many private servers up for testing. Hang out on the IRC channel (Freenode #opensim), and troll for URI's.

There are also several private organizations offering directories and search engines. They include:


 * Hyperica -- a categorized directory of hypergrid-enabled OpenSim destinations, currently over 250 locations
 * MetaverseInk -- ha key-word-based search engine for OpenSim grids, mostly those running the Diva Distro
 * GridHop -- a list covering the major OpenSim grids, currently over 150 destinations accessible over hypergrid teleport
 * HGURL -- a key-word-search database covering mostly destinations on the French-language FrancoGrid and related grids, all accessible via hypergrid
 * The Hypergates -- a directory of hypergrid-enabled destinations part of a hypergate teleportation network

Can I teleport from the Linden Lab Second Life grid to my Sim? (updated!)
Yes and No, Since the new public beta, launched on july 31th 2008 by Linden Lab, it is now possible to connect opensim servers/regions with the Second life grid, however this is not intended for regular users. NOTE: currently it ONLY works with the preview/beta grid of second life, not the main grid.)  It's in an early development stage and thus geared towards developers of virtual world/techniques, and is all but easy to setup. Furthermore, when an avatar is hopping from an SL region to an Opensim region, the avatar will be "ruthed", meaning it will be the default Secondlife avatar. NO assets (incl, shapes, skins, clothing etc) are tranfered during teleport, hence you wont have access to them, on the other grid. The beta test, is currently focussing on Teleportation between grids mainly. In the future, it should be possible to teleport WITH asset tranfers. But that wont be happening any time soon. If you want to try it out, read this page for more info on how to get started (with all the risks involved, don't say i didn't warn you): http://blog.secondlife.com/2008/07/31/open-grid-public-beta-begins-today/ For normal operation, stick to the regular versions of opensim.

How do I isolate and delete a user's Trash items in a MySQL grid database?
NOTE: BACK UP YOUR DATABASE!

CAUTION: The Linux default directory for the MySQL database is /var/lib/mysql Many backup tools (e.g. backupPC) do NOT back up /var/*! Make certain that the database and not just the MySQL code (/usr/bin/mysql) is included in your nightly backups! The actual paths will be different for different operating systems and databases, but the problem is the same.

1. Locate the avatars UUID you wish to find the trash items of, in the users table

This query will locate a specified users UUID: (replace User/Test with username/lastname) SELECT `UUID` FROM `users` WHERE `username` LIKE 'User' AND `lastname` LIKE 'Test' LIMIT 0, 30;

2. Use the avatars UUID to search the field_name AgentID in the inventoryFolders table, using Trash as the folderName to isolate the users Trash folderID

This query will locate the users Trash folder entry: (replace 00000000-0000-0000-0000-000000000000 with UUID of user) SELECT `folderID` FROM `inventoryfolders` WHERE `agentID` LIKE '00000000-0000-0000-0000-000000000000' AND `folderName` LIKE 'Trash' LIMIT 0, 30;

3. Use the folderID UUID obtained in the last query to find all of the trash items in the inventoryitems table, you can then delete them once you have isolated them.

This query will locate the trash items of the avatar in question: (replace 00000000-0000-0000-0000-000000000000 with Trash folder UUID obtained in the last query) SELECT * FROM `inventoryitems` WHERE `parentFolderID` LIKE '00000000-0000-0000-0000-000000000000' LIMIT 0, 9999;

 NOTE:  These steps will not remove the associated assets from the assets table, just the items in the inventory inventoryitems table.

How do I isolate and resolve duplicate inventory folder entries in a MySQL grid database?
NOTE: BACK UP YOUR DATABASE!

1. It's first a good idea to search for the affected avatars UUID in the inventoryFolders table to see the duplicate entries. When you see this, you'll see the problem of duplicate entries. The key here will be to find out which is being used.

2. Upload a file inworld and name it something unique. This will isolate the UUID of your root folder that is being used (even though there are dups only one is being used)

3. Search the inventoryitems table for your uniquely named item and locate it's parentFolderID

This query will isolate the parentFolderID based on your search for the unique item (replace unique_name with your unique item name) SELECT `parentFolderID` FROM `inventoryitems` WHERE `inventoryName` LIKE 'unique_name' LIMIT 0, 30;

4. Check the inventoryfolders table against the parentFolderID UUID obtained in the last search. That is your root folder that is being used.. you can delete all duplicate entries that do not match that parentFolderID. In the end, you should only have one of each type (Trash, etc)

This query will return all values that are NOT the parentID obtained in the last search. (replace 00000000-0000-0000-0000-000000000000 with the parentID located in step 3) SELECT * FROM `inventoryfolders` WHERE `folderID` NOT LIKE '00000000-0000-0000-0000-000000000000' LIMIT 0, 30;

Does in world scripting work yet?
Not fully implemented, but there is a lot of work going on here. Please see ScriptEngines, LSL Status and OSSL Status for the latest info.

Why do I walk through objects?
Basicphysics doesn't support collisions between objects (just between you and the ground). There is active work on other physics engines for OpenSim, the one that does most of the job and is most stable is the ODE (Open Dynamics Engine), which can be configured for use in OpenSim.ini.

Can I customize my avatar?
Yes. In order to do this:
 * Click the Inventory Button
 * Create -> New Clothes -> Shirt, Pants, etc
 * Create -> New Body Parts -> Hair, Shape, etc
 * Edit those from your inventory
 * Wear them

Your avatar doesn't always face a nice direction for doing this, so you'll need to use the camera operations to see your face for some of the modifications. This is a known issue, will be fixed in the future. Also, you'll need to rewear you parts once you first join the environment. Right now default appearance is always "Ruth".

Why do I look like I gas cloud right after I did the the previous steps?
Second Life eliminated Ruth from their client. The Ruth we see in OpenSim is our own attempt of a yoga teacher and not truly Second Life's Ruth. When you create a shirt, pants, skin and shape and wear them without changing any parameters, the Second Life Viewer understands you are not Ruth. Since Ruth is no more, you become a cloud of gas. To fix it, either change a parameter of one of them before wearing all 4, or, if you already are a gas cloud, right click one of these items in your inventory and click edit. That should bring up the edit appearance menus. Just move any sliders and voilá.

Why don't my terrain settings and prims stay through restarts?
You haven't set it up to use a database. See OpenSim Database support for info on how to set it up to use a database. (SqLite is the easiest of these to set up and should probably be used by anyone unfamiliar with any of the options).

I used XEngine, but my recent update caused DotNetEngine to come on again
There were some changes and you will need to change or create the line DefaultScriptEngine = "XEngine" in the startup section to get XEngine back. See ScriptEngines

Why doesn't my world map update when I edit the terrain?
There are three approaches depending on just how adventurous you want to be. From the least to the most adventurous:
 * Wait two days. You will need to restart your sim at the end of the two days to get the updates.
 * Exit the .xml file for the region. Change the value in the "lastmap_refresh" attribute to "0".  You will need to restart the sim.
 * Not for the faint of heart! Edit the "WorldMapModule.cs" file and change the "LazySaveGeneratedMaptile" method to change the "RefreshSeconds" value to something less than two days.  Be sure to read the comments and understand why things are the way they are.

Once your terrain stabilizes, this won't be much of a problem, but it is nice to see the updates while you're furiously developing something.

Why are my knees bent when I stand idle?
This seems to be a result of the ODE Physics Engine on 64 bit systems. A fix is to edit OpenSim.ini and change the following line: to
 * av_capsule_standup_tensor_linux = 550000
 * av_capsule_standup_tensor_linux = 1700000

Note that this line of code is under the [ODEPhysicsSettings] section of the OpenSim.ini file.

when I create a new skin and shape, the thing goes bonkers creating new assets constantly
you have not configured an asset cache

you need to configure either the cenome cache or the flotsam cache

without an asset cache, temporary assets can't be held which means they are continously rerequested

copy either config-include/CenomeMemoryAssetCache.ini.example, or the relevant flotsam file, to .ini edit and set it up for your needs then check GridCommon.ini or StandaloneCommon.ini uncomment the line for that cache

(standalone defaults to cenome grid to flotsam)

After the shiny new grid is running, what is next?

 * Make sure one can stop/restart UGA &S (sims). Check out any ordering issues of stop/restart UGA w/o stop/restart sim(s).
 * Make sure one can add/delete both a region and a user from the database.
 * Make sure it runs overnight and check it each morning by logging into 1 or 2 key sims.
 * 'tail -f userserver.log' and watch/understand the login process.
 * Make sure when you logoff your system, you can log back on and get control of the UGAS consoles.

Information about your regions.
Region statistics such as region name, avatar name, avatar position, number of prims, and a lot of other information can be obtained on a web page by: [WebStats] enabled=true For example- http://127.0.0.1:9000/SStats/ The resulting web page is continually updated using AJAX, so there is no need to refresh the page to obtain current information. One possible use for this web page information would be to see who is logged on to the region in real time - without actually logging in. This web page provides region information similar to the kind generated by using various server console commands to obtain region statistics. See Server_Commands
 * Adding the following to the bottom of the OpenSim.ini  file
 * Using a web browser and typing in the "Login URI" + "/SStats/" of your standalone server.

You guys like April 1st, eh? Looks like the joke is on us...
Yes, every year we've had a piece of non destructive code in the unstable, unreleased, upstream subversion tree. The source tree that is only designed for testers and developers. In each case it has shown something that is possible in OpenSim that most people might not have realized. In 2008 this was an avatar created entirely from a Region Module (no user), in 2009 it was making all users a giant (and I mean giant) stick bug avatar. There will be more in the future, don't worry. The developers seem to have a sense of humor.