> 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/sel-faq/using-the-software/calculation-modules/foundations2/general-footing-by-fem/why-wont-my-model-run.md). # Why won't my model run? Why a General Footing by FEM model fails to run due to too many shells from small or closely spaced pedestals. ## Why won't my model run? Problems can occur when a model has too many shells. "Too many" is subjective, but start thinking about this if the number of shells is higher than about 5000. Pedestals are meshed into a fixed number of shells. So if small pedestals are defined, this will lead to a large number of shells within the footprint of the pedestals. And part of the magic of this module is that the meshing algorithm ensures that the meshes under the pedestals are tied in with the mesh in the surrounding area of the footing. So having small pedestals results in many tiny shells in the footing *around* all pedestals. Working outward from there, the program has built-in parameters to ensure mesh quality. These control how rapidly the size of the shells can change, as it attempts to conform to the "target" shell size for the footing. So small pedestals, and closely located pedestals can have a significant impact on the total number of shells in a model. --- # 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/sel-faq/using-the-software/calculation-modules/foundations2/general-footing-by-fem/why-wont-my-model-run.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.