Acute Angle/Triangle

an angle/triangle with an angle smaller than 90°


the material needed for a specific component-“We must allow this much extra”. Usually a seam for connection


the intersection point of a cone, as seen in the elevation view


a portion of a circumference

Auxiliary Line

an extra element line added, different from the standard divisions


to divide in half


a straight line from 2 points on a circumference


the distance around a circle, perimeter of a circle


the distance across a circle at center, twice the radius

Elbow Rule

the number of pieces of a round elbow times 2 then minus 2(# of pcs x 2-2) gives us the number of gores in the elbow

Element Line

a line representing an edge or bend

Elevation View

looking at the front or side of something, to have elevation (height), 2D


a cone with the top cut parallel to the base


a part of a round elbow which allows us to calculate the miter angle


a line/plane level with the horizon. Flat, level


an intersection of 2 pieces- an irregular cut on the end of something

Obtuse Angle/Triangle

an angle/triangle with an angle larger than 90°


a line/plane that is equal distance from another


the shape of the object, still in 2D form


a line/plane which is 90° to another

Plan view

looking down at something, a “birds eye view”, “floor plan” (2D)

Point of Tangency

a straight line that touches the circle at only one point


a half of a plan view, drawn on the outside of an object


a sector which equals one quarter of the area of a circle


the distance from center to any point of the circumference, half the diameter

Right Angle/Triangle

an angle/triangle which has a 90° angle


the area of a circle bound by 2 radii and an arc


the area of a circle bound by an arc and a chord

Slant Height (small or large)

the hypotenuse of a cone, outside edge. The slant height is always a true length in the elevation view


a shape which has been “stretched out”, to take a perimeter and make it straight

Stretch-Out Angle/Arc

the angle or arc which encompasses a radial line pattern


a line which touches only 1 point of a circumference

Triangulation from Plan View

the length of an element line, set 90° to the vertical height, gives the true length of that line

True Length

a dimension or line that is not distorted by the view

True Length Diagram (TLD)

a 90° corner in that we use to find the actual length of a line


the point at which an angle is formed


a line/plane straight up and down, vertically level (plumb)


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Pattern Development: Sheet Metal Level 1 Copyright © 2021 by Brian Coey is licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted.

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