> For the complete documentation index, see [llms.txt](https://docs.enercalc.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.enercalc.com/e3d-training-manual/analysis/specifiying-and-performing-the/analysis-options/thin-plate-versus-thick-plate.md). # Thin Plate versus Thick Plate Option How to select between the thick-plate MITC4 and thin-plate Kirchhoff bending formulations for shells. The option to select the plate bending formulation for shells is located in the *Analysis Options* dialog, which can be opened by clicking **Analysis > Analysis Options**. By default, the program uses the MITC4 for shell bending formulation. The MITC4 is a thick plate formulation that accounts for the out-of-plane shear deformation. However, if the shell elements are all rectangular, you may use the classical Kirchhoff plate bending formulation. The Kirchhoff plate element is a thin plate formulation that ignores out-of-plane shear deformation. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://docs.enercalc.com/e3d-training-manual/analysis/specifiying-and-performing-the/analysis-options/thin-plate-versus-thick-plate.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.