axonometric pictorial + 3 types
object is rotated relative to the picture plane and projected with parallel projectors
(no vanishing points)
- isometric
- dimetric
- trimetric
explain how a cube would differ amoung the 3 types of axonometric pictorials
for all boxes, the edge would face towards the viewer.
The following is referring to the axes placed on this top most corner:
1. trimetric: no equal angles. no equal axis scales. none of the sides will look actually square
2. dimetric: 2 equal angles, 2 equal axis scales. two of the sides will look actually square
3. isometric: 3 equal angles, 3 equal axis scales. all of the sides will look actually square
oblique pictorials
parallel projection but one face of the object is kept parallel to the picture plane; appearing as true shape and size
axonometric vs oblique pictorials
axonometric: an edge/axis will be facing the viewer
oblique: a face will be facing the viewer
cabinet oblique + advangtage
half depth: reduces depth exaggeration
perspective pictorials
projection lines converge and create vanishing points.
true measurement is not preserved
(think of drawing lines from a dot to draw cubes in art class for “perspective”)
2 categories of linesin isometric drawings
- isometric: lines are parallel to one of the three isometric axes
- nonisometric lines: lines that are not parallel to one of the three isometric axes
best axonometric view for hand sketching
iso
boxing in method
- draw a box using isometric axis.
- each face of the orthogonal view coincides with a side of the box
how to draw circles/ellipses in isometric view
- draw a cross that is parallel to the iso axis. this is used to find the centre of your ellipses
- draw a v-shape with the centre in one corner. each line goes to the intersection of the radius of the circle/positioning cross. This should be opposite to the centre of the v, to the left or right
- repeat, putting the centre of the v shape in the corner directly opposite of the original.
- use the v-shapes to draw 4 arcs. connecting from cross line to cross line
isometric view, hidden edges rule
hide unless necessary
should you dimension an isometric view
typically no. if it is, never use as scale
ANSI rule when dimensioning (rare) iso views
use unidirectional dimension text
(parallel to the bottom of the page, even if dimensions are at an angle)
aligned dimensioning
dimensioning text in line with dimension lines
isometric projection foreshortening percentage compared to actual + how do we deal
81.6%
drawings are down at a 1:1 scale, which results in a drawing that is ~22.5% larger than a true projection
how is a sphere affected by isometric drawing
its the same (a circle)
