Hidden Line Representation

The VTYP (view type) command controls the hidden-line representation of pictures. Six possible VTYP settings are provided. These give progressively greater graphical accuracy at the expense of increasing processing requirements. The facility allows you to produce preliminary and intermediate drawings (where graphical accuracy can be of secondary importance) quickly, leaving only finished drawings to incur the greatest processing overhead. The default VTYP setting is WIRELINE, which gives a conventional wireline picture.

Modelled Wireline representation gives slightly greater realism by blending the intersection of primitives, but without incurring the computational overheads of removing hidden lines.

Wireline Hidden Line Removed representation produces a View where hidden lines are removed from individual significant elements (EQUI or SUBS) but not from items hidden behind them.

Local Hidden Line representation gives a picture where hidden lines are removed from individual significant elements (EQUI or SUBS), but not from items hidden behind them.

The representation differs from Wireline Hidden Lines Removed because individual significant elements are properly modelled so that intersections between primitives and holes display correctly.

Global Hidden Line representation gives a picture where all hidden lines are removed.

Universal representation gives a picture where all hidden lines are removed (as in Global HLR), but in addition intersection lines between clashing significant elements (for example, EQUI and STRU or SUBS and SUBS) are generated. Whether you need to use this View type depends on the way in which you have created the 3D model. The need for VTYP UNIVERSAL is greater if the 3D model is composed of a large number of significant elements each with a small number of primitives, rather than vice versa. It is also more likely to be needed in non-orthogonal Views, where missing intersection lines are most noticeable.

Alternative methods of setting VTYP are: