Galicia PAU Technical Drawing Applied to Plastic Arts and Design II flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Golden ratio value

φ = (1+√5)/2 ≈ 1.618. A segment is divided so that the whole relates to the major part as the major part relates to the minor part, giving self-similar proportions used in layout and composition.

Thales semicircle theorem

An angle inscribed in a semicircle is a right angle. It is used to construct tangents from an external point to a circle by drawing the circle whose diameter is the segment joining the point and the centre.

Regular polygon side formula

For a regular n-gon inscribed in a circle of radius R, the side length is s = 2R·sin(π/n). For example a hexagon has s = R and a square has s = R√2.

Inversion of a point

Point P' is the inverse of P with respect to a circle of centre O and radius r when OP·OP' = r². Circles through O invert to lines not through O.

Dihedral system definition

A representation system that projects an object orthogonally onto two perpendicular planes, horizontal and vertical, which are then unfolded onto a single plane to give two related views.

Quadrant of a point

The quadrant depends on the point's position relative to the horizontal and vertical planes. In the first quadrant the point is above the horizontal plane and in front of the vertical plane.

Right-triangle true length

To find the true length of an oblique segment, construct a right triangle whose legs are the segment's projection and the difference in depth of its endpoints. The hypotenuse is the true length.

Plane traces in dihedral

A plane is defined by its horizontal trace, where it meets the horizontal plane, and its vertical trace, where it meets the vertical plane. Both traces intersect on the ground line.

Isometric axonometry axes

Three axes are drawn at 120° to one another. Isometric drawing uses true scale along each axis; true isometric projection multiplies lengths by 0.816 to account for foreshortening.

Cabinet projection

An oblique projection with the front face drawn true size and parallel to the picture plane. The receding axis is drawn at 45° and at half scale to reduce apparent distortion.

Vanishing point rule

The vanishing point of a family of parallel lines is the point where the picture plane meets the line through the station point parallel to that family. All lines of the family converge there.

Cone of vision limit

The useful field of view in perspective is limited to a cone of roughly 30° to 60°, commonly 45°. Objects outside it appear distorted, so the station point distance controls deformation.

ISO 216 paper ratio

The A series uses the ratio 1:√2. A0 has an area of one square metre; each subsequent size halves the previous area, giving A4 = 210 × 297 mm.

Scale notation

Scale equals drawing dimension divided by real dimension. A 1:50 scale means one unit on the drawing represents fifty units in reality; the scale is stated in the title block.

ISO 128 line types

Continuous thick lines show visible outlines; continuous thin lines show dimensions and hatching; dashed lines show hidden edges; dash-dot lines show centre and symmetry axes.

Geometric tolerance frame

A rectangular frame containing a symbol for the characteristic, the tolerance value and optional datum letters. It defines permitted deviation of form, orientation or position under ISO 1101.

Kerning versus tracking

Kerning adjusts spacing between specific letter pairs such as AV or To. Tracking adjusts uniform spacing across a range of text. Both affect legibility differently from leading.

Point and pica units

One point equals 1/72 inch, about 0.3528 mm. Twelve points make one pica. These units measure type size, leading and rule thickness in typography.

Gestalt proximity principle

Elements placed close together are perceived as a group. Designers use proximity to create visual hierarchy and to signal which items belong to the same information block.

Double Diamond model

A design process model with four phases: Discover, Define, Develop and Deliver. The first diamond expands then focuses on the problem; the second does the same for the solution.

Exploded view purpose

A drawing that separates components along their assembly axes to show parts, order and relationships. It communicates assembly sequence and is common in product manuals and technical documentation.

Anthropometric percentiles

Body measurements are expressed in percentiles. Designs typically use the 5th percentile for reach and the 95th percentile for clearance so that most users are accommodated.

Design brief contents

A document stating the problem, target user, functional requirements, constraints, aesthetic criteria, budget and timeline. It guides the design process and provides criteria for evaluation.

Additive colour mixing

RGB primaries are red, green and blue. Mixing all three at full intensity produces white. It applies to screens and light, unlike subtractive CMYK mixing used in print.

Subtractive colour mixing

CMYK primaries are cyan, magenta and yellow. Mixing all three in theory gives black; black ink K is added in practice for depth and to save coloured ink.

Hue, saturation, value

Three attributes of colour: hue as an angle on the colour wheel, saturation as purity or chroma, and value as lightness. Munsell uses hue, value and chroma instead.

Simultaneous contrast

Described by Chevreul: a colour appears shifted toward the complement of its surrounding colour. It explains why the same grey looks different on light or dark backgrounds.

Vector versus raster

Vector graphics store geometry as points, lines and curves and scale without loss. Raster graphics store pixels in a grid and lose quality when enlarged beyond their resolution.

Parametric sketch constraints

Geometric relations such as coincident, parallel, perpendicular, tangent and equal constrain sketch entities. Driving dimensions set sizes, and changing a parameter updates the model.

CAD exchange formats

DXF and DWG exchange 2D drawings; STEP and IGES exchange 3D solid models; STL and OBJ carry meshes for 3D printing and rendering; PDF delivers final drawings.

Boolean modelling operations

Union combines two solids into one; difference subtracts one from another; intersection keeps only the shared volume. They are fundamental operations in solid and parametric modelling.

Print resolution and bleed

Raster images for print are typically 300 dpi at final size. Bleed, usually 3 mm, extends artwork beyond the trim edge so cutting tolerances do not leave white borders.