BSi Flashcards
Projection line
Continuous thin line for projecting between views.
Outline solid
Continuous thick line for visible edges and outlines.
Hidden detail line
Dashed thin line for hidden detail.
Centre line
Long dash — dot chain line for centres of symmetry.
Long dash — short dash chain is also acceptable.
Used to show the centre of shapes, for example a circle. Can be abbreviated to CL.
Fold line
A thin double-dash chain line to indicate folds on surface developments.
Cutting plane
Continuous thin line for projecting between views. Shows where an object has been cut or sectioned.
Leader line
Narrow lines which lead from points on a view to the arrowhead dimension lines. A small gap should be left between the view and the leader line.
Common tolerance
The Common method shows the upper limit of the size placed above the lower limit.
Asymmetrical tolerance
The
Asymmetrical
method shows the nominal size plus the upper and lower limits of the tolerance.
Symmetrical tolerance
The Symmetrical method shows the nominal size and the symmetrical tolerance expressed as a plus and minus.
Functional tolerance
A dimension that is essential to the function of a component or space.
Non-functional tolerance
A dimension that is not essential to the function of a component or space.
Projected edge
To select an edge from a CAD model or feature and generate it as a new line in a sketch.
Fixed
To hold a 3D CAD model in a fixed point, without applying any constraints.
Usually applied to the first component in an assembly.
Irregular fillet
A rounding of an edge, where the radius will change.
Irregular chamfer
The removal of an edge by a cut, where the distance changes along the length of the edge.
Intersect
Two 3D CAD features that pass through one another, with the result that only the area that the two touch remains. Everything else is deleted.
Datum
A key point in which dimensions, sizes and other details are taken from.
Sub-assembly
An assembly of components that is added to another, larger assembly.
Suppress
To turn a feature or command off within the modelling tree.
Wire frame
A method of presenting a 3D CAD model, showing only the edges. Faces are transparent.
Modelling tree
The linear hierarchy of how a 3D CAD model is created or assembled.
Sited environment
An environment that represents how the 3D CAD model would look in a realistic environment.
STEP/IGES
STEP and IGES files are a method of sharing 3D CAD components and assemblies between CAD platforms. Widely used for stock or library components.
Combined Dimensioning
Combined Dimensioning is a combination of parallel and Chain Dimensioning that can be used when space is very limited or the drawing is complex.
Hatching line
A 45 degree line which shows the surface produced by a cutting plane.
Dimension line
Indicates the size of a edge or face.
Types of building drawings
Location Plans
Site Plans
Floor Plans
Elevations
Sectional Views
Location (block) plan
The location plan identifies the location of the building or construction site in relation to its surroundings. It also helps the builders to plan the layout of the building.
Location plans include:
All neighbouring buildings and their plot boundaries
Street names
Roads, pavements, footpaths etc.
A north direction arrow
The scale of the drawing.
Location plan scale
1:1250
Site plan
Site plans show the site boundary and
the outline of the proposed development. Site plans show a larger view of a plot, normally highlighted in the location plan. The builder needs to know exactly where the plot of the building is to be constructed.
Site plans include:
Boundaries of the plot
The position of the building within the plot
Access paths
Trees
Drainage information; pipe runs, manholes etc.
Contour lines, indicating the slope of the ground
A north direction arrow
The scale of the drawing
Site plan scale:
1:200
Floor plan
The floor plan is an internal view of a house from above. It is used by all trades to plan their work.
It allows us to see the arrangement of the rooms, the position of windows and doors as well as the thickness of internal and external walls etc.
It gives information to trades people (builders, joiners, electricians, plumbers) but also used to show the client or customer the layout and dimensions of the house before it is built.
Floor plans include:
The layout and dimensions of rooms
Positions and sizes of windows and doors.
Layout of the kitchen and bathroom fixtures and fittings
Lamps, switches, sockets etc.
The scale of the drawing
Floor plan scale
1:100 or 1:50
Elevations
Elevations are orthographic views of the outside of the building that enable clients and customers to see what the finished building will look like.
Elevations include:
The style of the building
The external proportions of the building
The external features of the building; windows styles and wall finishes.
The type of roof
The position of the doors and windows from the outside.
Elevation scale
1:100 or 1:50
Sectional views
Sectional views are detailed technical drawings showing a slide through a wall. The section is normally taken through a part of the building that will show most detail.
A cross section through the side of a building gives builders, joiners and roofers all the information about how the building should be constructed. For example, details like the choice of materials, the design of the foundations and how all the different parts fit together should all be shown
on this type of view
Sectional views include
The materials used: brick, timber, concrete etc.
Construction details.
Dimensions
The scale of the drawing.
Sectional view/section scale
1:20
Illustrations
Rendered illustrations promote the house and give potential buyer an idea of what it will look like when it’s complete. The aim is to make the image look realistic and attractive to clients; this can be done by creating a pleasant surrounding.
These illustrations are easier for the public to understand as there are no technical graphics to over complicate them.
Nowadays, technology has advanced to allow 3D animation ‘walk through’ videos, to give an even clearer representation of a building.
Schematic drawings
Heating engineers, electricians and plumbers all work from drawings called schematic diagrams. They are used to present complex 3D installations in an easy to read 2D format.
