1. Solid-Modelling-Internals

3. The modeller Geometry Kernel The Husk GUI.stl.sldprt.sat

4. Basic Components GUI-provides a rendering/viewing facilities. Provides modelling ease Husk-Implements operations, controls and manages the parametrization and the solid Kernel-maintains the basic geometry. Answers geometric queries posed by the husk.

5. Post-Modeller Analysis Husks In this case: Curvature Analysis

6. GSSL Husks –AFR/FeatureWorks –CFL/Blend Recognition and Suppression –CollabView –CAMWorks The Husk-Kernel Interface is very important

7. The GUI Present a Co-ordinate system Make selection and design of entities easy Provide interfaces to down-stream analysis and recently Provide for collaborative design! GUI can make-or-break

8. The Husk Front Office Implements Operations (gets it done from the kernel). - extrudes/revolves/sweeps -extract parameters and use kernel operations Maintains design tree and modifications and alerts user! -maintains the sequence and dependence of the operations -maintains parameter consistency

9. The Husk Back Office Maintains relationships between geometric entities -such as between counter-bores/assemblies -across features Re-sequences operations -roll-back and re-do -record such inter-dependency

10. Implements operations…. 1.Takes the scribe and prepares the Cylinder. 2.Subtracts the cylinder

11. Maintains and updates design tree….. Deepen the hole Alert The User!!

12. Relationships between geometric quantities…. Maintain co- axiality of the two cylinder axes Counter-Bore Holes

13. Re-sequences operations Desired Husk Operation. Kernel Operation Blend the edge first. Then do the boss

14. Kernel Maintains the solid as faces/edges/vertices Implements operations such as booleans, offsets, and even blends Supplies answers to geometric queries

15. Routine Operations Booleans blends

16. A typical Query… Does the curve C2 on face F intersect the curve C1?

17. Another query from a CAM husk What is the distance between faces S and S’? CAM picture S S’ Can the ball cutter go in?

18. Kernel Operations Kernel typical APIs: Is this point on this face? Find the closest point to p on surface S Intersect solids B1 and B2 Compute tangents

19. The B-Rep of a solid Boundary of a solid as a closed surface. Inside/Outside and a outward normal Surface composed as a collection of faces/edges/vertices Face Edge vertex

20. Basic Entities Face-the 2d-fragment of a surface. Edge-the 1d fragment of a curve Co-edge-edge as an element of a face Vertex-0d element of design space. All quantities in design space Two-tier representation - combinatorial or topological - parametric or geometric

21. Topology Adjacency relationships between face/edge/vertices Orientation All objects here have the same topology.

22. Topology cont. Face-a collection of loops Loops-sequence of signed edges Edge-ordered pair of vertices Vertices-just a Set

23. Applications of Topology Husk: check topology! And alert user.

24. Applications of Topology-II Kernel:Helps in sequencing intersections. If F intersects F2 boundary along e1, then F1 is next.

25. Wrap-Up The GUI-Husk-Kernel trichotomy Husk-as the legislative body of operations Kernel-as the executive body Kernel Representation: Geometry/Topology Topology Details