Material Assignments All objects in the ECOTECT model can be assigned two different material, refered to as their primary and alternate materials. When an object is initially created its default alternate material is the same as the primary material. The effect of selecting a different alternate material depends on the element type of the object. For objects such as WALLS, ROOFS, FLOORS, and CEILINGS the alternate material is used whenever the object overlaps another object belonging to the external surface of another zone. For WINDOWS, DOORS, PANELS, VOIDS, APPLIANCES, LIGHTS and SPEAKERS the alternate material is used only when the object is activated.

Material assignments can be changed or updated at any time using the Material Assigmnents panel or the Selection Information panel.

Primary Material This specifies the material the element is constructed of. These are selected from a library of materials and define the performance properties of the object. For information on material properties, see the Material Properties dialog box. You can assign materials to any object(s) using either the Selection Information or the Material Assignment panel.

Alternate Material One of the fundamental features of the ECOTECT model is editability, the ability to be able to drag around and rearrange zones very quickly and easily. When two zones are positioned right next to or on top of each other, there will be some portions of a WAll, FLOOR or CEILING that overlap similar elements in the adjacent zone. In a real building, it is unlikely that the same material will be used in the overlapping and non-overlapping sections, thus the alternate material is used for any overlapping areas to represent this variation.

Defining an alternate material allows you to move zones around as much as you want without ever having to worry about how much of a particular WALL will be external cavity-brick, for example, and how much will be internal single-brick. Simply assign cavity-brick as the primary material of the WALL and single-brick as the alternate. The area of each section will be automatically determined during the next Inter-zonal Adjacency calculation. This only applies to ROOF, FLOOR, CEILING and WALL elements.

For WINDOWS, DOORS, PANELS, VOIDS and SOURCES (SPEAKER, LIGHT and APPLIANCES), the alternate material is used when the object is activated. An object can be activated to simulate opening a WINDOW at a particular time or turning on a heater (APPLIANCE). During the activation period, the alternative material replaces an object's primary material in time-based calculations. For more information, see the Object Activation topic.

Cross-Assignment Because different architectural elements of a building do different things, they need different types of information to describe their performance characteristics. Thus each material in the material library is assigned an element type, a WALL, WINDOW, LIGHT, SPEAKER or APPLIANCE, for example. Similarly each object in the model is also assigned an element type.

It is possible to assign a material of a different element type to that of its assigned object. For example, you may want to assign the same alternate material to a CEILING object as is assigned to the FLOOR of the adjacent zone immediately above. This is possible because both types of element have the same thermal data as each other. ECOTECT will detect the cross-assignment and adjust thermal values to reflect the reversed layer order (upside-down instead of downside-up).

However, not all element types contain the same data. For example, a CAMERA will not have a U-Value but will have a Lens Type and View Angles. Similarly, a WINDOW material has a U-Value and Admittance the same as a WALL, but has a Shading Coefficient and Alternating Solar Gains instead of Solar Absorption and Thermal Lag/Decrement values. For accurate thermal calculations you should avoid inappropriate cross assignments, such as assigning a WALL object a WINDOW material. This will not make the WALL into a WINDOW, it will simply generate a warning and mean that values for alternating solar gain will be erroneously used in place of thermal lag and decrement properties.

As explained above, ECOTECT is reasonably tolerant allowing you to cross-assign WALLS, FLOORS, CEILINGS, ROOFS, PANELS and DOORS as their materials all have the same information types. However WINDOWS, VOIDS, SPEAKERS, LIGHTS, APPLIANCES, LINES and POINTS all have unique material information so cross-assignment generates a warning message.

For more information, see the Element Types topic.

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