Experiment with thin walled shapes

[raydeleu]

As an experiment to show the features of CascadeStudio I wanted to create something like a Mollino coffee table.

The base consists of a piece of plywood with holes that is pressed into a curved shape. I think that the most logical way to model this starts with a surface with holes which is then thickened. The following image compares this approach to creating a solid first and the cutting the holes into this shape. You can clearly notice that the thickness of the plywood is not even around the holes. The image was created with Moi3D.

I started with creating the wavy surface in CascadeStudio. Then I tried to offset this shape. However, offsetting a surface creates another surface, not a shelled solid. Furthermore it seems that the offset function in CascadeStudio cannot handle a face with holes. Therefore I had to resort to the method to create a solid first. I achieved this by extracing a wire from the two surfaces first and then using a loft between these. I then stenciled the holes using some rotated cylinders. Finally I applied a fillet to the edges of the cut to hide the fact that the holes are not cut normal to the local surface.

// define points of wavy curve
let p0 = [0,0]
let p1 = [50,45]
let p2 = [100,3]
let p3 = [130,65]
let p4 = [150,40]
let points = [p1,p2,p3,p4]

// create sketch of wavy curve and rotate it to XZ-plane
let sideView = new Sketch(p0)
.BSplineTo(points)
.End().Wire()
sideView = Rotate([1,0,0],90,sideView)

// create to random cylinders to cut holes in the shape
let cyl = Translate([10,55,0],Rotate([1,0,0],30,Cylinder(8,100,false)))
let cyl2 =  Translate([114,15,0],Rotate([1,0,0],-30,Cylinder(13,100,false)))

// extrude the curve, create a copy and offset this copy
let base = Extrude(sideView,[0,60,0])
// It does not work to stencil the holes out first and loft the wires later. 
// This is probably caused by the GetWire function that only converts the outer
// boundary of a face to a wire.  
// base = Difference(base,[cyl,cyl2])

let base1 = base;
base1 = Offset(base1,1);

// to create a solid, make wires out of the two surfaces and loft 
// between them 
let baseComplete = Loft([GetWire(base),GetWire(base1)])

// add some fillets to the holes to disguise that these are not
// cut normal to the face direction 
baseComplete = Difference(baseComplete,[cyl,cyl2])
baseComplete = FilletEdges(baseComplete,0.4,[10,18])