DITTO:

An image (or occurance) of the geometric elements of a detail which is transferred into another workspace is called ditto.

A ditto can be used as a single element, but its constituent geometric elements can be used for further creations in the receiving workspace.

If the geometric elements of the initial detail are modified, all the dittos are automatically updated

The ditto mode is useful:

1. To keep a subset independent from the rest of the model

2. To place several identical subsets in the model, while creating them only once in the model (memory space saving)

3. To allow easy modification of a repetitive subset. Such a modification is applied to each occurrence of the model

Applns.: Mainly used in designing

1) Piping and

2) Tubing

DRAFTING:

Dimension is composed of several elements called dimension components,dimension line,extension line, leader,tolerence,associated text, numerical value and end symbols.

Dual dimensionis created like a simple dimension, the tolerence is displayed in the numerical format as expected. Main value and dual value are tolerenced with deffer-

Ent tolerence types.

Dimension system is a set of simple dimensions created one after the others. To create a dimension system, the presentation mode has to be defined. Either chain mode or stacked mode must be used.

In Chain mode, simple dimensions appear one after the other

In stacked mode, simple dimensions are positioned one above the other,in parallel, all dimension values are expressed in relation to acommon reference point.

DESCRIPTIONS :

Descriptionse groups of parameters which are used to defined asingle concept and are managed as a whole. There are five types of descriptions.

1) numerical display format , which enables youn to express numerical value of a model in the unit we want.

2) Framing of a dimension text can be constant or can vary according to the extent rectangle.

3) Character graphic aspects, ie character font, slant, spacing, hight ,width and width/hight ratio.