> For the complete documentation index, see [llms.txt](https://manual-2.karamba3d.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://manual-2.karamba3d.com/3-in-depth-component-reference/3.4-joint/3.4.3-line-joint.md). # 3.4.3: Line-Joint The "Line-Joint"-component lets one specify linear hinges inside or at the boundary of shell-patches. ![Fig. 3.4.3.1: Line-joint symbolized by a purple line between two shell patches "A" and "B"](/files/-MgplL81abIByBtKOXlP) Fig. 3.4.3.1 shows an example which involves two shell patches "A" and "B" made up of two shell elements each. Patch "A" is fully fixed on one side and connects to "B" via a linear joint symbolized by a purple line. Shell "B" can rotate about the joint's X-axis given by the read arrow on the purple line. The "Line-Joint"-component provides these inputs to specify the non-rigid connections between shells: * "J-Curve": A line-like curve which connects the nodes of shell which are part of the line-joint. The direction of the curve specifies the joint's X-direction. * "AtElemId": Identifier of the shell patch on which the joints shall be specified. The default is an empty string which signifies that the joijnt is potentially attached to all shells in the model. * "Y-Ori": sets the joint's local Y-axis. It points towards the shell patch on which the joint shall be attached. When "Joints" is enabled in the "ModelView"-component the Y-axis appears as a green arrow on the hinge line. * "Z-Ori": In case the joint's Y-direction is (0,0,0) or parallel to the joint-line direction, the joint's tripod gets created via the joint-line's X-direction and the Z-orientation. The joint gets attached to those elements which the joints Y-axis points to. The Z-axis is symbolized by a blue arrow when displayed via the ModelView-component. * "DAlpha": Maximum angle \[deg] between a mesh-face and the Y-Ori for adding a line-joint to it. * "Ct": Vector of translational spring stiffness of the line-joint.Values take effect only, if the corresponding DOF is set to hinged in the "Dofs"-input of via the radio buttons in the submenu "Joint definition". * "Cr": Vector of rotational spring stiffness. Is analogous to "Ct". * "Dofs": List of degree of freedom indexes (0:Tx, 1:Ty, 2:Tz, 3:Rx, 4:Ry, 5:Rz) to be released in addition to those selected via the check-boxes in the sub-menu "Joint definition". Add a 'ValueList'-component for easy selection or use 'Expand ValueLists' from the component's context menu. The radio-buttons under "Joint definition" signify released joint DOFs when enabled. In order to see the joint's local coordinate system enable "Joints" in the "Display Scales"-submenu of the "ModelView"-component. The "Local axes"-slider in the same submenu can be used to scale the arrows. {% file src="/files/4eeehJjwGqhg6cEBjXJZ" %} {% file src="/files/xuQu89MqUaxW5pF5aAbk" %} {% file src="/files/bKi8MXxw2oyQABc28H47" %} --- # 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://manual-2.karamba3d.com/3-in-depth-component-reference/3.4-joint/3.4.3-line-joint.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.