Launch Formlt and go to Plugin Manager in the right-side toolbar. You’ll find the plugin under the Recommended section.

FormIt offers built-in diagnostics to identify issues with solid models.

• Go to the Visual Styles palette.
• Click on the Diagnostics tab.
• Enable Watertight Issues and Back Faces.

Validate Model

Use Validate to check for geometric corruption that could result in modeling failures. 

Clean Model

Use Clean to fix issues found in the Validate step.

Note that Clean may delete invalid geometry and may change the appearance of the model. 

You have the option of changing the tolerance value before clicking Clean Model.

• A tolerance value of 0 will fix invalid geometry found during validation.
• Higher values will delete and merge any edges in the model that are shorter than the provided tolerance.