Examples of PolyfaceClip methods

Cut Fill

red and green meshes
Compute "over and under" mesh parts (red is meshA, green is meshB)	const cutFill = PolyfaceClip.computeCutFill(meshA, meshB);
cutFill.meshAOverB	`
cutFill.meshBOverA	`

Unit Test

• source: imodeljs\core\geometry\src\test\clipping\PolyfaceClip.test.ts
• test name: "CutFill"
• output: imodeljs\core\geometry\src\test\output\PolyfaceClip\CutFill.imjs

Section Cut

grey: closed volume mesh green: section plane
extract linework of section cut	const section = PolyfaceClip.sectionPolyfaceClipPlane(facets, clipPlane);
This produces an array of LineString3d
Clip the facet set and produce facets on the cut plane
insideClip is a boolean controlling which side of the cut is kept.	` const clippedPolyface = PolyfaceClip.clipPolyfaceClipPlaneWithClosureFace(facets, clipPlane, insideClip, true);'
Lower and upper parts

Unit Test:

• source: imodeljs\core\geometry\src\test\clipping\PolyfaceClip.test.ts
• test name: "ClosedSection"
• output: imodeljs\core\geometry\src\test\output\PolyfaceClip\ClosedSection.imjs

Clipping with ConvexClipPlaneSet or UnionOfConvexClipPlaneSet

gray box is a closed volume mesh Red shape is to be swept vertically
Create SweepContour as intermediate step to UnionOfConvexClipPlaneSets for the clipping.	const contour = SweepContour.createForPolygon([Point3d.create(xA, yA), Point3d.create(xB, yA), Point3d.create(xA, yB), Point3d.create(xA, yA)])!;
Get the clipper out of the SweepContour	const clipper = contourP0.sweepToUnionOfConvexClipPlaneSets()!;
Create a ClipBuilders object for use in the clip	const clipBuilders = ClippedPolyfaceBuilders.create(true, true, true);
Do the clip	PolyfaceClip.clipPolyfaceInsideOutside(facets, clipper, clipBuilders);
Extract the inside part	insidePart = clipBuilders.claimPolyface(0, true);
Extract the outside part	insidePart = clipBuilders.claimPolyface(1, true);

Unit Test:

• source: imodeljs\core\geometry\src\test\clipping\PolyfaceClip.test.ts
• test name: "BoxClosureNonConvex"
• output: imodeljs\core\geometry\src\test\output\PolyfaceClip\BoxClosureNonConvex.imjs

Last Updated: 11 June, 2024