> 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/building-the-model/general-modeling-theory/understanding-model-geometry/shells/order-of-nodes.md). # Order of Nodes How shell node numbering affects warping, top and bottom orientation, load application, and the interpretation of results. The order of the nodes defining a shell is important for a few reasons relating to numerical behavior, load application and interpretation of results. To satisfy numerical behavior, it is important to define quad shells by either numbering their nodes sequentially clockwise or counter-clockwise. Specifying a quad shell by using a crisscross numbering order will result in a "warped" shell. These look like a bowtie, and they do not perform properly. Shells have a top and a bottom which have meaning in terms of the output. To determine the orientation of a shell, use the fingers of your right hand to trace around the nodes of the shell in order from Node 1 to node 4. Your right thumb will naturally point in the direction of the "top" of the plate. The shell below was drawn from node 1 to 2 to 3 to 4, so we are looking at its top. ![](https://3750289988-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FlRZtG5Ynp58kYzLHYbR7%2Fuploads%2Fgit-blob-52a143a8b88a821306c60ffb871fe085617b982e%2FShell%20with%20nodes.jpg?alt=media) Do not be too concerned with the orientation of shells during the modeling process, because there are some simple ways to orient groups of plates consistently once they have been modeled. These will be discussed in the section on Editing Model Geometry. --- # 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/building-the-model/general-modeling-theory/understanding-model-geometry/shells/order-of-nodes.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.