31372 - Computer-Aided Drawing L

Learning outcomes

The course aims to provide the necessary basis for the understanding of the main features of the most modern programs of Computer aided design ( CAD ) and for the proper use of such programs as part of the Technical Design . The course consists of a first part dedicated to ensuring students learning the basic rudiments of the Technical Industrial Design . In the second part of the course discusses the issues of its computer-aided design and describes the principal methodologies used in modeling , editing , coordinate transformation and visualization of curves , surfaces and solids .

Course contents

COMPUTER TOOLS
Architecture of a CAD (Computer Aided Design). Hardware: computer, dynamic memory (RAM), mass storage (HDD), flexible disks, CD-ROM. Data input: keyboard, mouse, tablets digitalizzatrici, scanner. Output: Display Devices vector and raster-scan, hard-copy devices (plotters, dot matrix, inkjet, laser). Software: interface with the operator, defining and designing the model, image generation (rendering), database management, applications, utilities. Advantages and limitations of CAD.

Raster and vector graphics

Notes on raster and vector graphics with particular attention to the use in CAD systems.

USE OF A CAD

The graphics primitives, the initial settings of the design, how to enter data, how to select objects, editing commands objects, the ability to display, how to support the targeting, the use of layers, the use of blocks, dimensioning of a drawing, text, headers, and squaring, raster images, the backgrounds, the use of paper space, the problems of the press, simple graphics primitives, the graphics primitives complex, the design of a relief, the blocks attributes.

Basic geometrical construction
Bisecting a segment of an arc, of a corner. Perpendicular to a segment (a straight line) from a given point: external, belonging to it (center or end). Parallel to a given line (at a given distance, for a given external point). Transactions related to corner. Trisection of the right angle and angle plate. Division of a segment into equal parts. Tangents to a circle from a point outside or belonging. Circle with given radius tangent to a straight line in one of its points. Bribes internal and external to the two circles. Circle through three points, fittings line and circumference with arc of given radius. Regular polygons: triangle, square, pentagon, hexagon and octagon with side assigned or circumscribed circle. Construction of a polygon with a number of side given the length side or the circumscribed circumference. Plane curves (ellipse, parabola, hyperbole, oval, ovolo, evolving in circumference).

Study and comparison of systems snapping and snapping OBJECT in the CAD system.

THE Orthogonal projection method
Representation with orthogonal projection on two orthogonal planes of points, lines, planes. Conditions of membership of a point and a straight line and plane, and point plan. Terms of coplanarity, incidence and parallelism for lines; of parallelism between floors. The third plane of projection: determination of the third projection of points, lines, planes, curves. Orthogonal projection of plane figures and solids. Criteria for the identification and representation of the lines in sight and no.

VERA shape of plane surfaces
General. Method of tipping. Rollovers of points, lines, segments, plane figures lying in planes perpendicular to the principal plane of projection.

Geometric primitives in MODEL SPACE and SPACE PAPER.

Axonometric projections OBLIQUE, orthogonal and future
Reduction factors. Axonometric oblique unified (cavalier; UNI 4819). Parallel perspective orthogonal or isometric orthogonal. Axonometric isometric unified (UNI 4819). Axonometric representation of flat surfaces, prisms, pyramids; Exact and approximate representations of circles, curves and solids of revolution. The concept homography and stereograph.

SECTIONS
Aim of sections: ideal plane of section. Plane sections of prisms and pyramids. Sections of solids of revolution (cylinder, cone, sphere, torus). Determination of the contour lines of the sections: method of generating and auxiliary method of section planes. Solids obtained by section plane (frustum of a pyramid, cone, cylinder oblique, etc ...). Use the PATTERN for obtaining the backgrounds in the CAD system.

Interpenetration OF SOLID
General. Interpenetration of prisms and pyramids. Specific use of the auxiliary section planes. Determination of the intersection line on the interpenetration of solids of revolution: method of the generatrices, the method of the auxiliary plane section, method of auxiliary spheres.

Dimensioning
Basis, dimension lines and reference, layout and reading of the shares. Dimensioning systems (in series, in parallel, overlapping dimensions, dimensioning combined, in coordinates, polar coordinates). Particular agreements of dimensioning (solid of revolution, circles, spherical surfaces, square, chamfers and rounding elements regularly or irregularly arranged). Criteria for selection of the reference elements and general rules for proper dimensioning.
Using the controls of DIMENSION and their setting for correct dimensioning of the drawing.
8 - OPERATING PRINCIPLES OF SYSTEMS CAD 3D
Coordinate systems and reference systems
· Coordinate Systems:
· Cartesian coordinates
· Cylindrical Coordinates
· Spherical Coordinates or Polari
· Coordinates Homogeneous
· Reference systems
· Local
· Global
· Observer
· Views
Onscreen representation of graphics primitives and outline of the classical algorithms.
UNITA 'Basic geometrical
Methods of representation of the main basic geometric units.
Transformations:
· Offsets
· Rotations
· Transformations of scale
· Symmetry and Reflection

Readings/Bibliography

CHIRONE, TORNINCASA, Disegno Tecnico Industriale, ed. Il Capitello, Torino.

CONTI, Disegno tecnologico, vol. 1, 2, ed. Pitagora, Bologna.
SOBRERO, Corso di Disegno, solo vol. 1, ed. Pitagora, Bologna.
FILIPPI, Disegno di Macchine, vol. 1, 2, ed. Hoepli, Milano.
Mortenson, Modelli geometrici in computer graphics, McGraw-Hill.

Teaching methods

The course is based on theoretical frontal lessons in the classroom and guided laboratory exercises.

Assessment methods

The final exam consists of an exercise in interpretation and execution of drawing to computer.

Teaching tools

The course involves the use of computer lab computers capable of managing interactive 3D graphics.

Links to further information

http://diem1.ing.unibo.it/personale/liverani/teach_resources.htm

Office hours

See the website of Alfredo Liverani