Different Representations:

A typical axonometric view of a block (say a huge rectangular building), as if the viewer is swinging round the block in a helicopter steeply banking (with its axis inclined), so that the ground seems to be sloping, and horizontal and even vertical lines are tilting.

However, the displayed image shows even the lines that are supposed to be hidden and hence invisible, interfering with and disturbing our perception of the object. Essentially, the surfaces are all transparent and the edges are all of visible, leading to ambiguity and confusion. For instance, which of the two comers is nearer to the viewer : P or Q? This will be a problem in whatever view of the object we wish to display.

This skeletal view is called as Wire-frame Model. Although not a realistic representation of the object, it is still very useful in the early stages of image development for making sure that all the corners and edges are where they should be. For some situations such as preliminary designs, centre-line diagrams of structural frames, so on. these are not only quite' sufficient, but even preferred over the more realistic views.