There is such a variety of different plastic products available that it is difﬁcult to generalize about their properties and aesthetics. However, the majority of plastics are malleable, synthetic materials made of macromolecules. They share some key characteristics, as all plastics can be processed easily and with a high degree of accuracy. Their rigidity combined with light weight properties makes them highly useful in models for which other materials would not be suitable.
One of the most common plastics used in modellingis polystyrene, as it is mass-produced and inexpensive.This makes it ideal for a range of uses. Some architects and model makers only work with polystyrene, particularlywhen developing ideas, as the material can be workedwith quickly and easily. Consequently, a special type of design and presentation has emerged for constructing architectural models. Polystyrene is typically white and smooth, although blue styrofoam and pink rigid foaminsulation are also common, and therefore ideal fordetailed work and complex, organic forms. Its ﬁnelytextured surfaces afford a smooth ﬁnish, and modelsproduced using this material alone offer a degree ofabstraction, allowing the formal qualities of the designto be fully appreciated. This versatile plastic can be easilyhand-cut and formed using scalpels or craft knives as wellas machined. There are a number of styrene brands with the main suppliers being easily sourced at good hobby,model and craft shops. It typically comes in either sheetor strip form. As a sheet material, styrene can be used toconstruct model facades, landscape and details. Texturedsheets can provide a contrast for material representation.Generic brickwork and paving sheets come across assomewhat toy-like so are rarely used in commercialmaking. Styrene strip provides a huge range of shapesand sizes in basic construction forms. More speciﬁc formssuch as structural ‘I’ beams are also available and lendthemselves perfectly to structural and cross-section models.
A high degree of precision can be achieved whenworking with plastics – a feature which frequently setsthem apart from other materials. It is possible to makecomponents to an accuracy of fractions of a millimetre,which is a great advantage for numerous different typesof models and makes it highly suitable for some CAD/CAM processes that will be described later in this section.Of particular signiﬁcance is the fact that plastics can beused to represent transparent components – for example,glass – by incorporating thin sheets or foils of transparentpolyvinylchloride (PVC). Plastics are thus a vital materialfor architectural modelling. Another frequently usedplastic in architectural modelmaking is acrylic glass oftenjust referred to as acrylic. Its versatility and relative lowcost allows it to be easily worked using a variety of hand skills and or machine processes. Acrylic is available ina wide range of thicknesses and colour ﬁnishes. Thereare many brand names that are often confused to be thematerial name such as Perspex and Plexiglas but theseare simply two types of acrylic available and widely used,which visibly appear almost identical.