Look Direction

The View’s line of sight is fully defined by any two of:

• Looking Direction

• From Point

• Through Point

which are defined by the attributes DIR, THPO and FRPO. Setting one of these unsets one of the other two, assuming they are both already set.

DIR (Direction) specifies the Looking Direction, down by default. The attribute is set by commands, for example:

LOOK E

LOOK N45W

ISO3

PLAN

DRAELEVATION N

IR D

Note that the picture produced by changing the Looking Direction does not necessarily fit into the VIEW frame.

The THPO (Through Point) attribute is set to the Design coordinates corresponding to the centre of interest of the view. These are calculated automatically from the VIEW’s related Id List by the AUTO command.

FRPO (the From Point) is the position (in Design coordinates) at which the observer is deemed to be.

The Through Point and From Point can be set explicitly by commands, for example:

LOOK THROUGH N53426 W632764 U2125

LOOK FROM N53426 W632764 U2125

FRPO N125671 E67342 U11254

THPO N125671 E67342 U11254

Changing the Direction, Through Point or From Point makes the existing VIEW graphics out of date, so this must be updated by typing

UPDATE DESIGN

before any change in the picture is seen.

The 3D view direction equivalent to 2D Sheet direction can be queried using

Query VIEWDIRection <sheet-dir>

where <sheet-dir>is Left, Right, Up or Down. The command gives an error when the VIEW has Perspective or the current database position is not at or below a VIEW.

For example, in a plan VIEW with RCODE UP (the default), then the query

Q VIEWDIR LEFT

gives:

Viewdirection Left W

However, for a plan VIEW with RCODE LEFT, the result is:

Viewdirection Left N

and for a plan VIEW with ADEG 120 (and RCODE UP) the result is:

Viewdirection Left E 30 N