> 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-user-manual/interface/toc175916526/toc175916652/member-properties/toc161393859.md). # Materials How to define and assign material properties such as modulus, Poisson ratio, and density to elements. Create (or Modify) > Member Properties > Materials prompts you with the following dialog. ![](https://560001759-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FWNe8U6EBBBdUJHdb2X9G%2Fuploads%2Fgit-blob-b82ff9c24d7ee0e684661999e37e3b574975cf7c%2FFASTFR~1_img75.png?alt=media) It allows you to define and/or assign materials to selected elements in the model. An ID is assigned automatically to each material by the program and may not be changed. You may assign a label with 127 maximum characters to each material for easy identification. The material properties include: * Young’s modulus (E), * Poisson ratio (0 ≤ ν < 0.5), * Weight density, * Temperature coefficients. The shear modulus (G) is calculated automatically. These material properties are used in the structural analysis of the model. Material properties related to design may be set from design ribbons. For example, concrete strength f'c and reinforcement strengths fy and fys may be defined from Design > RC Materials. You may add standard steel and concrete materials by clicking the “Std Materials” button. A standard material label starts with “Steel” or “Concrete”. You may add one or more materials by clicking the “New Rows” button. You may also print all materials in the list by clicking the “Print” button. The “Assign active material to currently selected elements” checkbox may be used to assign the active material to selected elements. The active material refers to the one that currently has focus in the list in the dialog. In order for material assignments to take place, members, shells or bricks must be selected beforehand. *A more flexible way to assign material and other properties to entities is to use* ***Modify > Member Properties*** *or* ***Modify > Shell Properties*** *command, which allows you to continuously assign one or more properties to entities.* The program always has a default material labeled “Default”. You may not delete this material or change its label. You may, however, change its properties. --- # 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-user-manual/interface/toc175916526/toc175916652/member-properties/toc161393859.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.