License Glossary FAQs


An entitlement is a "voucher" for a license(s) that you are entitled to install on any of your machines. An entitlement may be for a new license, or an extension/upgrade/increment to an existing installed license.

Entitlements are transformed into licenses when you log into the licensing system and "redeem" them. When you redeem an entitlement, you bind it to a specific license server machine and you turn it into a license tied to that computer. Also, a license expiry date (if any) is calculated based on the redemption date rather than on the purchase date.

It's something like a movie ticket. The ticket isn't the movie itself (the thing you paid for), but it allows you to go in and watch the movie. In the same way, the entitlement is not a license (you can't run Houdini with it), but it allows you to come and get a license from Side Effects Software.


To redeem a license means trading in an entitlement for an actual license. This is accomplished through the License Administrator, or manually via

After you have redeemed the license (ie. converted your entitlement into a license), the entitlement you had is no longer valid and cannot be used again (because it's been converted into a license), unless you return the license later.


Returning a license means that the installed license will removed from the machine it is installed on and be placed back onto your account as an entitlement. You will then be able to re-redeem the entitlement onto a different machine or the same machine.

Some reasons for customers to return their licenses back to SideFX:

  1. License Type upgrades
  2. Product Type upgrades
  3. Moving the licenses onto a different license server
  4. Converting a license mask to match specific subnets (eg. 192.168.5. * , 10.0. * . *)

Note: When you return your licenses back to SideFX, the licenses still stay on your account unless they are being exchanged or converted, at which point, you will be issued a new set. Returned licenses remain on your account as a holding place until you are ready to re-install.

There is a limit of 3 returns.


A piece of data installed on the your License Server that allows you to run a specified number of Houdini products.

Licenses are created to be installed either the computer itself as a node-locked license or onto a single license server, to serve licenses out onto the network.

Users sometimes mistake a License for a Token. A license just means that you are allowed to serve/use a certain product. A license may have many tokens. "Token" means that "x" number of copies of that product are able to be run at the same time on different machines (unless the License is a workstation license).

For example a License of Houdini FX may have 10 tokens. This means that this particular License of Houdini FX may be used on 10 machines simultaneously.

There are several types of licenses:

  • Server license
    This allows the machine to serve licenses. This is automatically generated when a Product license is installed for the first time.
    This license begins with the SERVER keystring.
  • Product license
    This is the main type of license, which can be for any of the Houdini products. The license includes a token count, IP mask and expiry date, among other things.
    This license begins with the LICENSE keystring.
  • Upgrade license
    This upgrades an existing product license to a newer version of Houdini. e.g. upgrade 9.0 to 9.1
    This license begins with the UPGRADE keystring.
  • Extension license
    This extends the expiry date of an existing license to another date sometime in the future.
    This license begins with the EXTEND keystring.
  • Increment license
    This increases the number of tokens of an existing license.
    This license begins with the INCREMENT keystring.
License Administrator (aka hkey)

The License Administrator is a graphical utility that allows you to check the status of installed licenses, install new licenses, return licenses, and diagnose licensing problems. It does not display the actual encrypted keystrings.

The License Administrator simplifies license installation by sending your server name and server code to Side Effects Software when installing entitlements or returning existing licenses. You should always try to use the License Administrator for license management.

Please refer to How do I start the License Administrator? to run.


A helper program on the user's machine that communicates with the License Server to retrieve licenses. When Houdini is run on an artist's machine, it asks hserver on his machine to get a license. hserver then asks the License Server for a license.

Only one copy / one version of hserver is ever running at one time on any given machine.

On Windows, this program can be started and stopped in Services as HoudiniServer.

Server code

A unique code that identifies a machine to our licensing system. When licenses are created, they are valid only for one server code.


See License Server

License Server

(aka sesinetd)

The program that serves licenses. It is responsible for keeping track of how many licenses are available and checked-out.

On Windows, this program can be started and stopped in Services as HoudiniLicenseServer.


If you are unable to run the graphical License Administrator (hkey), you can use sesictrl, which is a command-line utility to manage your licenses. Please refer to the section How do I use sesictrl? in the License Management section of the FAQ for more information.

License Diagnostic

If you are having difficulty with licensing on the server or client, the diagnostic information can be sent to the support team at Side Effects Software. This file contains detailed information about the licensing setup that can be used to help diagnose and resolve the problem. Please refer to the section About Licensing.


Each license specifies how many copies of a Houdini Product that can be run at the same time. This number is referred to as a "token". For example a license of Houdini FX could allow up to 20 copies to be run at the same time. This license would have 20 tokens (or you could say that there are 20 copies of FX with the same License ID).

Running any number of copies of Houdini FX, Houdini or Houdini Batch on the same machine uses one token.

For example, If your facility had 20 copies of Houdini FX and you opened 2 copies of Houdini FX on your workstation, Houdini would use 1 token out of 20 because you're opening all the FX on your local machine. The facility has 19 tokens left for different clients (different machines).

From version 13.0.301, Mantra tokens are now consumed the same way as Houdini itself, ie, one per machine.

Floating License

A floating license is a network license. It may be used on a network so that any client on the network may acquire a token.

Workstation License

A workstation license may only be used on the machine it is installed on. It cannot be used on a network. Both the server and client components are installed and used on the same machine.


A license may be keyed to be used on a specific network class or a list of specific networks.

A workstation license has a subnet mask of +.+.+.+. This means that only the local machine that the license is installed on may run the software.

The + represents the network portion of the address.

A floating license may have different types of subnets.

  • class C = +.+.+.* (eg. 192.168.5 network)

  • class B = +.+.*.* (eg. 192.168 network)

  • list of specific networks (eg. 192.168.*.*, 10.1.*.* etc)

By default, Class C masked keys are issued unless specified otherwise.

Class A (+.*.*.*) licenses are normally not issued. Please speak with your Account Manager.

Non-restrictive licenses (*.*.*.*) are never issued.