Oblong and Oblong Void works as original 3DS Max primitives.

Once the scripts are installed go to the command panel on the right side and look at the rollout list selecting geometry button, Extra Primitives should appear at the bottom of the list. Click on Oblong or Oblong Void button to create your primitive, parameters can be changed in the modify tab.

The installer that ran when you downloaded this app/plug-in from Autodesk App Store will start installing the app/plug-in. OR, simply double-click the downloaded installer to install the app/plugin.

You may need to restart the Autodesk product to activate the app/plug-in.

To uninstall this plug-in, exit the Autodesk product if you are currently running it, simply rerun the installer, and select the "Uninstall" button. OR, click Control Panel > Programs > Programs and Features (Windows 10/11) and uninstall as you would any other application from your system.

The objects created with same length and width parameters will have slight color difference in the output.