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Projected Curve: This feature will take two sketches on two different planes and project them to where they intersect to produce one 3D sketch
Step 1
First: have your two sketches on two different planes ready
Step 2
2nd: go to Projected Curve
Step 3
3rd: select the two sketches, notice the projection type is "Sketch on sketch", this is a projected curve. After you select the two sketches SW will produce a preview result in yellow. Click the green check to accept and continue
Step 4
And here is the final result. Note the Curve feature in the tree; the two sketches used are under it (adsorbed) and can be modified is needed. :)