1. Read in the file flying_minnow_dirty.surf.gz. Then rotate the model so that the starboard wing, group "Right Wing", can be seen. For this tutorial, switch the viewing type for SurfGrid to "Wire/Shad"  . This will aid in viewing the results of the intersection after the repair is done.
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| 2.
Zoom in to the portion of the model where the Right Wing intersects the Fuselage. The intersection between the Right Wing and Fuselage can be easily seen. In previous tutorial CAD based repair techniques were used to repair this geometry. Here, though, we will repair the discrete intersection using discrete repair methods.
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| 3. .
Turn off the "Right Wing" group to verify that the Fuselage is not topologically adjacent to the Right Wing.
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4.
Toggle, press  , and press  to see just the Right Wing and notice that it is not topologically adjacent to the Fuselage and that it is open on one end with free edges (yellow triangles on the open end). Repairing the intersection will remove the free edges and make the Fuselage and Right Wing topologically adjacent so that further downstream applications, like volume grid generation, can use this mesh.
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| 5.
Turn back on all geometries and select the Right Wing and Fuselage surfaces or groups.
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6.
Next press the  button to intersect the geometries. The intersection algorithm will find the first intersection between the two selected surfaces, and then use discrete topological relations to "trace" the line segments that define the intersection between the two surfaces. Once the chain of line segments terminates either on a free boundary or a surface boundary, the intersection is considered repaired. Therefore if multiple intersections occur between two group or surfaces, multiple intersections will have to be performed with manual clean-up between intersections. The manual clean up is important because the intersection tool creates non-manifold edges but only repairs manifold, non self-intersecting meshes.
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| 7.
The intersection will create new groups if the intersection forms a closes loop with either itself or a free/surface boundary. In this case it formed a closed loop on both surfaces. Turn off the Right Wing group to see the results on the Fuselage. The greep surface in the middle of the Fuselage is bounded by the intersection and can be removed. Select it and delete it.
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| 8.
Now a hole exists in the Fuselage where the Fuselage was "inside" of the Right Wing. Selct the small surface inside of the Fuselage hole, which is the part of the Right Wing that was inside of the Fuselage, and turn it off.
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| 9.
Toggle, press , to see the results of the intersection of the Right Wing. The purple surface on the end of the Right Wing was what was inside of the Fuselage. The intersection formed a closed loop on the Right Wing surface and therefore that part of the Right Wing was made into a different surface so that it could be deleted. Select the purple surface and delete it.
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| 10.
Turn all of the surfaces back on and manipulate the model so that you can see the inside of the Right Wing from inside of the Fuselage. This is the best vantage point to see the cleaned up geometry. Notice that the part of the Fuselage that was inside of the Right Wing has been removed. Also, the part of the Right wing that was inside of the Fuselage was also removed. The result of the intersection and manual clean-up is manifold geometry with the intersection repaired.
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| 11.
This is a view of the outer surface of the Right Wing and Fuselage intersection. Again, only two surfaces can be intersected at a time and manual clean-up is required between each intersection to ensure that the mesh is manifold and non self-intersecting.
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