How to set normal direction for a hole?

Comments

• mahir Member, Developers Posts: 1,304 ✭✭✭✭✭

  February 2018 edited February 2018

  By default your extrude direction is dictated by the normal direction of the plane or surface that you sketched your point on. This is normally away from your part, which is usually the opposite of the direction of your hole. You can fix your default direction by just multiplying by -1. This will flip the direction. But it's a good idea to keep the invertNormal option just in case the user wants to flip the direction. Also, you can use the OPPOSITE_DIRECTION UIHint in order to make the interface match what you would normally see - a double arrow instead of a checkbox.
  
  
  

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• robert_morris OS Professional, Developers Posts: 168 PRO

  February 2018

  If you want the code to figure out which direction to extrude automatically, you can try to extrude it in one direction, and then extrude in the opposite direction if there was an error. That's what I do in my Mounting Boss featurescript.
  
  So looking at your code, you could try something like this:
  

  var extrudeDefinition = {
                      "entities" : qSketchRegion(id + "frontSketch", true),
                      "direction" : sketchPlane.normal,
                      "operationType" : NewBodyOperationType.REMOVE,
                      "defaultScope" : true,
                      "endBound" : BoundingType.UP_TO_SURFACE,
                      "endBoundEntityFace" : definition.backface
                  };
  // Try to extrude in the normal direction first.
  // If that direction fails, then try again in the opposite direction.
  try silent
  {
      extrudeDefinition.oppositeDirection = false;
      extrude(context, id + "extrude1" + unstableIdComponent("Normal"), extrudeDefinition);
  }
  catch (error)
  {
      if (error.message == "EXTRUDE_FAILED")
      {
          extrudeDefinition.oppositeDirection = true;
          extrude(context, id + "extrude1" + unstableIdComponent("Reverse"), extrudeDefinition);
      }
      else
      {
          throw error;
      }
  }
  

  
  

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• lana Onshape Employees Posts: 703

  March 2018

  In our feature implementations we usually take an approach of specifying 

  "Editing Logic Function" for the feature, which is executed during feature editing and can initialize some feature parameters based on simple analysis. e.g. flip of up-to-face extrude is computed by shouldFlipExtrudeDirection() function in extrude.fs, flip of hole direction - by holeScopeFlipHeuristicsCall in hole.fs  . This way in simple case editing logic method guesses right and when it does not, the user can override its decision.

  More here: https://cad.onshape.com/FsDoc/uispec.html#editing-logic-function

  0
• Jake_Rosenfeld Moderator, Onshape Employees, Developers Posts: 1,646

  March 2018 edited March 2018

  @nikolas_engelhard
  
  You are calling 'extrude' with a 'direction' parameter.  You'll notice that there is no 'direction' parameter in the 'extrude' documentation:
  https://cad.onshape.com/FsDoc/library.html#extrude-Context-Id-map
  This is because extrude uses evOwnerSketchPlane internally on its 'entities' input to find the direction.
  
  If you would like to manually specify the extrude direction, you can use opExtrude instead (but this function will not allow you to do the 'operationType' work you are trying to do, so I think 'extrude' is probably the right call to use):
  https://cad.onshape.com/FsDoc/library.html#opExtrude-Context-Id-map
  
  
  I think what you'll want to do is something like the following:
  

  // Find the point on the center of the back face
  const backFacePoint = evFaceTangentPlane(context, { 
          "face" : definition.backFace, 
          "parameter" : vector(0.5, 0.5)
      }).origin;
  
  // Construct the vector pointing from the center to the beck face point
  const towardsBackFace = backFacePoint - location;
  
  // extrude should be 'oppositeDirection' if the vector pointing towards
  // back face is not in the hemisphere "forward" of the sketch plane
  const oppositeDirection = dot(sketchPlane.normal, towardsBackFace) < 0;
  
  // Then use "oppositeDirection" directly in your extrude call

  
  

  Jake Rosenfeld - Modeling Team

  1
• nikolas_engelhard Member Posts: 5 ✭

  March 2018

  Thanks for your help! I used the analytical way from @Jake_Rosenfeld (now also with the added hole for the nut)
  

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• Jonathan_Hutchinson Member Posts: 89 PRO

  July 2023

  @Jake_Rosenfeld ; will the geometry.fs version of extrude() ever take a direction input? Asking since there are of course some options available there that are not within opExtrude.
  
  

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• chadstoltzfus Member, Developers, csevp Posts: 139 PRO

  July 2023

  @Jonathan_Hutchinson What exactly are you trying to do? Extrude will automatically extrude along the vector normal to the face selected, or you can use oppositeDirection if you need it flipped. If there needs to be along a different direction, you'll probably have better luck trying a sweep or loft. 
  

  Applications Developer at Premier Custom Built
  chadstoltzfus@premiercb.com

  0
• lana Onshape Employees Posts: 703

  July 2023

  Evailable now
  
  

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