--- title: Derived classes slug: task-view-guide/derived-classes docTags: createdAt: 2024-09-16T12:13:22.349Z --- Derived classes are new shapes created by combining existing ones. They help you generate useful new elements, like lines, based on the properties of other shapes. ::Image[]{src="https://api.archbee.com/api/optimize/wLEz_RbWP6nIMpY-prjlm/9AGAkFK80MHwhc9z0DsEP-20260527-070045.png" size="50" width="306" height="232" darkWidth="306" darkHeight="232" position="center" showCaption="false"} :::::ExpandableHeading ## Centerline A centerline is a new line generated in the center of two lines or lanes. ### How to use ::::WorkflowBlock :::WorkflowBlockItem Select "Centerline" from the list of derived classes. ::: :::WorkflowBlockItem Select the two lines for which you wish to create a center line. ::: :::WorkflowBlockItem Select what to base the centerline length on: "Same as selected" or "Selected + connected lines". *Selecting "Selected + connected lines" will generate a centerline between the selected lines and the lines to which they are connected.* ::: :::WorkflowBlockItem Select the class that the center line should have. ::: :::: ![](https://app.archbee.com/api/optimize/wLEz_RbWP6nIMpY-prjlm/UH5zz9_8qHwCU907Vpn5W-20251114-110412.gif "Workflow for generating a centerline") :::hint{type="info"} The centerline direction and the number of nodes included are determined by the first line or lane selected. ::: You can re-select which lines or lanes to generate the centerline from by clicking on the object ID chip and selecting another line in the view. ::Image[]{src="https://app.archbee.com/api/optimize/wLEz_RbWP6nIMpY-prjlm/ge9rVPymLER2VUUtLoZzO-20251114-111250.gif" size="60" width="772" height="602" position="center" caption="Re-selecting shapes" darkWidth="772" darkHeight="602" showCaption="true"} :::hint{type="info"} Centerline generation is only available in single-frame tasks, for shapes with world-interpolation set to true, and for aggregated lidars and camera sequence tasks. ::: ::::: :::::ExpandableHeading ## Lane connection A lane connection is a derived line that creates a smooth, connecting line between two existing lines or lanes. ### How to use ::::WorkflowBlock :::WorkflowBlockItem Select "Lane connection" from the list of derived classes ::: :::WorkflowBlockItem Select the two lines for which you wish to create a connection ::: :::WorkflowBlockItem Optional: Select curve type and adjust curve strength ::: :::WorkflowBlockItem Select the class that the lane connection should have ::: :::: :::hint{type="info"} The direction of the two lines you want to connect is important. Use the preview of the connection to be generated to view if the new line will look as you expect. ::: ![](https://api.archbee.com/api/optimize/wLEz_RbWP6nIMpY-prjlm/6-h5jLeEgOne1Wj55-_kn-20251209-135724.gif "A lane connection between two lines") ### Curve type and strength When you have selected the two lines to connect, you can choose a curve type, or adjust the curve strength. - **Soft **creates a smooth, gentle curve that follows the natural direction of the connected lines. - **Sharp** creates a tighter curve with a sharper angle. Adjust and preview the curve strength with the slider. :::hint{type="info"} Some connections will auto-generate a completely straight line between the two lines. **In these cases, the curve type selector is disabled** because a straight connection is the only appropriate choice. This happens when the second line is aligned ahead of the first one (sequential lanes going in the same direction). ::: ![](https://api.archbee.com/api/optimize/wLEz_RbWP6nIMpY-prjlm/jEm5yyUNwqKq1Pq7fbYLc-20251209-135805.gif "Adjust curve strength") :::hint{type="info"} Lane connection generation is only available in single-frame tasks, for shapes with world-interpolation set to true, and for aggregated lidars and camera sequence tasks. ::: ::::: :::::ExpandableHeading ## Combined line A combined line is a derived line that joins two or more existing 3D lines into a single connected line, with a node at every selected node. ### How to use ::::WorkflowBlock :::WorkflowBlockItem Select "Combined line" from the list of derived classes ::: :::WorkflowBlockItem Select two or more 3D lines that you wish to combine ::: :::WorkflowBlockItem Optional: Adjust the offset to push nodes outward (or inward) ::: :::WorkflowBlockItem Select the class that the combined line should have ::: :::: :::hint{type="warning"} The order in which you select the lines matters. The first selected line is used as the anchor and keeps its original direction; each subsequent line is appended to the end of the chain, and is reversed automatically if its other endpoint sits closer to the chain end. Use the preview of the generated line to verify that the result connects as you expect. ::: ![](https://api.archbee.com/api/optimize/wLEz_RbWP6nIMpY-prjlm/PNa8bt9McDgMcm4VPGlqE-20260527-071109.gif "A combined line between two lines") ### Offset When you have selected two or more lines, you can apply an offset to the generated nodes. The offset is given in centimeters and is applied perpendicular to each edge of the resulting line, treating the node sequence as a closed polygon. - **Positive** values push every node outward from the center of the shape. - **Negative** values pull every node inward. The offset is most useful when the combined line forms a closed (or nearly closed) loop, such as when you chain lines into a polygon outline and want to expand or shrink it uniformly. :::hint{type="info"} Combined line generation is only available in single-frame tasks, for shapes with world-interpolation set to true, and for aggregated lidars and camera sequence tasks. ::: :::::