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Projected Intersection - Best way to do it?

thomas_aathomas_aa Member Posts: 19 ✭✭
I often find that I need to create parts that are projections or intersections of two sketches/surfaces. What I usually end up doing is extruding first one sketch and then extruding the other, with Intersect.

Is there a better way (Fewer features)? I would almost expect a tool that can take the two sketches as input and output a solid of the projected intersection, but I have not done CAD professionally, so I'm really sure of what to expect.

Also, in this case, I can either do Through all in both directions for an extrude or do Symmetric with a large arbitrary value (so the Symmetric is much less cumbersome to input). Another choice is to extrude to vertex in two directions, matching the perpendicular sketch. Any preferences?

One could argue that I could have placed the sketches on "one side" so I can avoid the double extrusion, but I often work along the center symmetry of my part. (One option I see is to have my original sketches, then create a plane on one side and then create a second projected sketch, allowing for each extrusion to only have one direction.)




  • mahirmahir Member, Developers Posts: 1,213 ✭✭✭✭✭
    Two extrudes is pretty much the way to go. Either intersecting or removing material is fine, but I think intersect is more elegant. Extruding up to a surface works, but I believe it's marginally slower. Your particular example could be created via 2 sketches and one loft, but I don't think fewer features is worth using a slower feature - plus, you'd be limited to planar end profiles. If it's truly bothersome to use 2 extrudes, you can program a custom featuresript that accepts 2 sketches and creates a solid at their intersection.
  • NeilCookeNeilCooke Moderator, Onshape Employees Posts: 4,315
    Since you've drawn the 2 sketches first, you can use up to vertex when extruding.
    Director, Technical Services, EMEAI
  • mahirmahir Member, Developers Posts: 1,213 ✭✭✭✭✭
    edited June 2020
    NeilCooke said:
    Since you've drawn the 2 sketches first, you can use up to vertex when extruding.
    Mind you this will only work if one of your end faces is planar. If neither is perfectly flat, the general solution of 2 extrudes is still the simplest method.
  • thomas_aathomas_aa Member Posts: 19 ✭✭
    It's good to know that I've been using the correct technique. Thank you!
  • Evan_ReeseEvan_Reese Member Posts: 1,421 PRO
    Kinda seems ripe for a custom feature though if it comes up often. I vaguely recall this is how is expected Solidworks to behave when I first used it in 2010. 
    Evan Reese / Principal and Industrial Designer with Ovyl
    Website: ovyl.io
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