HEC applications offer a wide range of configurable settings that can be adjusted through configuration files or -D flags. These -D flags allow you to customize how individual plugins function, control the behavior of the main application, and set preferences for visualization.

Rather than modifying the default HEC-RTS configuration file (CAVI.config), you have the option to create a personal configuration file named CAVI-Personal.config. The key advantage of using a personal config file is that it’s independent of specific software versions. While CAVI.config must be updated each time you install a new version, CAVI-Personal.config remains consistent and applies across all versions. When present, the personal config file will override the default config file, allowing you to customize the behavior of HEC-RTS to better suit your needs.

This guide will walk you through the process of creating and editing a CAVI-Personal.config file tailored to your preferences.

Software Version

HEC-RTS 3.5 was used to create this tutorial.

Step 1: Open the ConfigEditor

By default, HEC-RTS looks for a personal configuration file at the following location: C:\Users\<USERNAME>\AppData\Roaming\CWMS\PersonalConfigs\CAVI-Personal.config.

You can create and edit this file using the ConfigEditor included with the HEC-RTS installation.

To launch the ConfigEditor:

  1. Open File Explorer and navigate to your HEC-RTS installation directory.
  2. Go to the \<HEC-RTS version>\common\exe folder.
  3. Double-click ConfigEditor.exe to launch the editor.

Step 2: Open the Default CAVI.config File

  1. In ConfigEditor, go to the File menu and select Open.

  2. Navigate to the \<HEC-RTS version>\CAVI folder.

  3. Open the CAVI.config file.

ConfigEditor will automatically generate a new CAVI-Personal.config file (if one doesn't already exist) at C:\Users\<USERNAME>\AppData\Roaming\CWMS\PersonalConfigs.

You should now see two tabs in the editor:

  • CAVI.config
  • CAVI-Personal.config

Step 3: Edit the CAVI-Personal.config File

  1. Click the CAVI-Personal.config tab.
  2. From the Edit menu, select Basic Settings.
  3. Set both the Initial Memory and Max Memory to 8192MB.
    1. If 8192MB isn't in the dropdown, you can type it in manually.
    2. It's recommended to set both values the same to ensure consistent memory allocation.
  4. To always show the Console Window, check the corresponding box.

  5. Click Save to apply your changes.

These changes will add three entries to the file:

  • Minimum memory
  • Maximum memory
  • Console window visibility


If you're not proceeding to the next step, you can now close the editor.

Step 4: (Optional) Add Additional -D Flags

You can further customize your configuration by adding -D flags:

  1. From the Edit menu, select Add Command.
  2. Choose the appropriate command type (e.g., vmparam).
  3. You will be given two options:
    1. Manual Entry: Type in the flag manually.
    2. Automatic Entry: Use the built-in dialog to select from commonly used flags.
  4. After adding the desired flag(s), save the configuration file you were editing.
  5. Close the ConfigEditor.

Refer to this guide for more information on available -D flag options and their use cases.