I am trying to break the extension line around the machining mark.
Have the break in the options set & also gone into edit dimensions.
There isn't currently a way to break dimension extension lines around any entities other than other dimensions. The work-around is to click on the dimension to highlight it, then click on the little blue box at the end of the extension line and drag it back past your leader. Then place a sketched line in the drawing view, make it colinear with the edge of the model, adjust it's endpoints so it looks correct in relation to the model edges and the leader line, and make it the same line style, weight, and color as the dimension's extension lines.
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