I am trying to re-size a part within an assembly. I need the length to be flush with a mating surface. I am able to drag the edge but I would want/prefer it to be an exact fit.
Use the Up To Surface extrude option.
You can also try the top down assembly style. You edit your part in the assembly and then "copy" the geometry to the part and then use that geometry to make your part features. I like to copy geometry to a part and then open the part by itself and work on it there.
2014 SOLIDWORKS Help - Top-Down Design
A basic tutorial on how to copy features.
SOLIDWORKS - Top Down Assembly Modeling - YouTube
A few things to note...this creates external references which is a not a bad thing but you have to be more careful with your files. I find that Solidworks does ok with this top down method, but it could be way better organized and robust. Creo is excellent with this and I typically only used Top Down with it, but with SW I find it harder to use.
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