Course Introduction to virtual engineering

Course Introduction to virtual engineering

Óbuda UniversityJohn von Neumann Faculty of Informatics

Institute of Applied Mathematics

Lecture and laboratory 2.

Solid modelingBoundary represented solid

László Horváth university professor

http://users.nik.uni-obuda.hu/lhorvath/

A prezentációban megjelent képernyő-felvételek a Dassault Systémes V6 PLM rendszerének, az Óbudai Egyetem Intelligens Mérnöki Rendszerek Laboratóriumában telepített installációján készültek, valóságos

működő modellekről, a rendszer saját eszközeivel.

Ez a prezentáció szellemi tulajdon. Hallgatóim számára rendelkezésre áll. Minden más felhasználása és másolása nem megengedett!

CATIA V5 PLM rendszer a Dassult Systémes Inc. és a CAD-Terv Kft segítségével üzemel laboratóriumunkban

László Horváth UÓ-JNFI-IAM http://users.nik.uni-obuda.hu/lhorvath/

Contents

Topological structure and rules

Euler rule and its application

Boundary representation

Lecture

Creating free form and generative curves and extrusions (VE2.1)

Creating surface based solid and its modifications (VE2.3)

Laboratory

Creating translate and blending surfaces (VE2.2)


Problem

F1

F2

G12

Solution:Boundary representation= topology (structure) and geometry (shape)

Geometry: surfaces and intersection curves

What is this?

Solid body seems

It consists of separated surfaces


Description of shape by its boundary

What is this?

Solid body seems

It consists of six separated

surfaces

Its construction



What happened?Translate.2 switched to hide and

the model was completed by two solids (Pad.1 és Pad. 2).


Boundary representation

V

E F

V = vertex

L = loop, ring

E = edge,

P = point

G12

C = curve

F = faceS = Surface

coedge

ShellConsistent(complete)

Shell + material = body

Boundary representation= topology (structure) and geometry (shape) Geometry: surfaces and intersection curves

Body = two lumps:


Topological rules

Three or more edges must run into a vertex.

Face must be enclosed by a closed chain of edges.

Edge is included always in two loops for adjacent faces.


Euler rule and its application

Leonhard Euler (1707-1783) Swiss mathematician.

Euler number for boundary of body: V - E + F

Euler number is a constant: V - E + F = C.

For simple bodies ( no through holes or separated bodies (lumps)): Euler number = 2

Examples:

V-E+F=8-12+6=2 V-E+F=10-15+7=2 V-E+F=2-3+3=2



What happened?Shape modification by form feature Hole.1 acts

on only solid features.


Modification of boundary by form features

Form feature Shell.1 acts on both of the lumps in the PartBody.

Form feature Hole.2 is after Shell.1 in the sequence. Shell.1 does not modify it.


Including surface in solid boundary

Surface 4 is a NURBS, it can be modified by control points. No flat constraint!

Surface 4 is extended at its edges.

Form feature ThickSurface.1 is defined between Surface.4 and its

offset. This is the third lump in the solid.


Modification of lumps by form feature

Form feature Pad.3

is defined by

closed free form curve in Plane.

and

appropriate surfacein the boundary of

form feature ThickSurface.1 .

Form feature Hole.3 modify all of the lumps in the solid body PartBody.


Creating free form and generative curves and extrusions

Laboratory task VE2.1

Creating free form curve by free definition of interpolated points.

Studying possibilities for the definition of a point.

Application of generative means at curve definition.

Creating extruded surfaces in the context of the above curves


Creating free form curve and its extrusion



Manual placing is allowed with restricted context




Creating points and generative curve by their interpolation


Creating points and generative curve by their interpolation


Creating extruded surface using generative curve


Creating translate and blending surfaces










Creating surface based solid and its modifications

Laboratory task VE2.3

Creating base feature between blend surface defined in task VE2.2 and its offset.

Modification of the solid by a prism form feature.

Modification of the solid by a fillet form feature.


Creating base feature between blend surface and its ofset


Creating base feature between blend surface and its ofset


Modification of the solid by a prism form feature








Additional modifications for the final solid


Documents

Course Introduction to virtual engineering