How To dimension Arc Length on SolidWorks Drawing.
1. Start the drawing of the part to be dimensioned & find the view best suited for the arc dimension.
2. Click Smart Dimension and select the arc you’d like to define.
3. Select an endpoint of the arc.
4. Select the other endpoint of the arc.
5. Arc length dimension is now given.
6. As a preference you can change the leaders to show radially.
7. More options can be found by clicking Tools>Options.. “Document Properties” tab, expanding the “Dimensions” drop down and clicking “Arc Length”.