How to use MakeThickSolidByJoin

[raydeleu]

I tried to use the function makeThickSolidByJoin from OpenCascade.js in a script, but one way or another it does not work.

let myBody = Box(20,20,30);
let thickness = 4;
let facesToRemove = [5,3];
let box_original = myBody;
myBody = new oc.BRepOffsetAPI_MakeThickSolid();
myBody.MakeThickSolidByJoin(box_original, facesToRemove, thickness, 1.e-3);
sceneShapes.push(myBody.Shape());
Translate([40,0,0],box_original,false);

The resulting shape seems to be a shell. I tried converting this to a solid using the following lines

solidBody = new oc.BRepBuilderAPI_MakeSolid();
solidBody.Add(myBody.Shape());

but this did not work. The other strange thing is that the resulting shape still contains the faces that were selected to be removed. The shape is only a shell that is offset from the original solid.

Can anyone help me find the error in my code?

[raydeleu]

In the code below I repeated the experiment shown above, but now using a function that closely follows the standard function for offset. The result is identical to my previous experiment: the function return an offset version of the original object, not a shelled version. For reference the code below produces both an MakeThickSolid and an Offset from the original shape, both are identical.

function Offset(shape, offsetDistance, tolerance, keepShape) {
  if (!shape || shape.IsNull()) { console.error("Offset received Null Shape!"); }
  if (!tolerance) { tolerance = 0.1; }
  if (offsetDistance === 0.0) { return shape; }
  let curOffset = CacheOp(arguments, () => {
    let offset = null;
    if (shape.ShapeType() === 5) {
      offset = new oc.BRepOffsetAPI_MakeOffset();
      offset.AddWire(shape);
      offset.Perform(offsetDistance);
    } else {
      offset = new oc.BRepOffsetAPI_MakeOffsetShape();
      offset.PerformByJoin(shape, offsetDistance, tolerance);
    }
    let offsetShape = new oc.TopoDS_Shape(offset.Shape());

    // Convert Shell to Solid as is expected
    if (offsetShape.ShapeType() == 3) {
      let solidOffset = new oc.BRepBuilderAPI_MakeSolid();
      solidOffset.Add(offsetShape);
      offsetShape = new oc.TopoDS_Solid(solidOffset.Solid());
    }
    
    return offsetShape;
  });
  
  if (!keepShape) { sceneShapes = Remove(sceneShapes, shape); }
  sceneShapes.push(curOffset);
  return curOffset;
}

function MakeShell(shape, facesToRemove, offsetDistance, tolerance, keepShape) {
  if (!shape || shape.IsNull()) { console.error("MakeShell received Null Shape!"); }
  if (!tolerance) { tolerance = 0.1; }
  if (offsetDistance === 0.0) { return shape; }
  let curShell = CacheOp(arguments, () => {
    let shell = null;
    if (shape.ShapeType() === 5) {
      shell = new oc.BRepOffsetAPI_MakeThickSolid();
      shell.AddWire(shape);
      shell.PerformByJoin(shape, facesToRemove,  offsetDistance, tolerance);
    } else {
      shell = new oc.BRepOffsetAPI_MakeThickSolid();
      shell.MakeThickSolidByJoin(shape, facesToRemove,  offsetDistance, tolerance);
    }
    let shellShape = new oc.TopoDS_Shape(shell.Shape());

    // Convert Shell to Solid as is expected
    if (shellShape.ShapeType() == 3) {
      let solidShell = new oc.BRepBuilderAPI_MakeSolid();
      solidShell.Add(shellShape);
      shellShape = new oc.TopoDS_Solid(solidOffset.Solid());
    }
    return shellShape;
  });
  
  if (!keepShape) { sceneShapes = Remove(sceneShapes, shape); }
  sceneShapes.push(curShell);
  return curShell;
}

let box_original = Box(20,20,30);
let thickness = 0.5;
let sidesToRemove = [];
sidesToRemove = [5];

let offset = Translate([0,40,0],Offset(box_original,-thickness,0.1,true));
let shell = Translate([40,0,0],MakeShell(box_original,sidesToRemove,-thickness,0.1,true));