DRAW110 Drawing a Volume -- Case 1

CALL GDRAW (CHNAME,THETA,PHI,PSI,U0,V0,SU,SV) Draws an orthographic parallel projection or a perspective projection of volume CHNAME according to the options set via the routine GDOPT and all its visible descendants (see routine GSATT to alter the visibility of a volume) at position U0,V0 (user coordinates), with the scale factors SU and SV; the object is seen from THETA and PHI angles, and the resulting 2D projection is rotated by an angle PSI on the screen plane. These parameters, as well as zoom parameters set by GDZOOM define the current view parameters, and they are copied in the common /GCDRAW/. Attributes like colour, surface fill, line width, line style, visibility, etc. can be set by calling the GSATT routine for CHNAME and its descendants [GEOM 500]. An example of the result of the call:

CALL GDRAW('ARM ',40.,40.,0.,nx,ny,0.015,0.015)

is given in fig for various values of the attributes and graphic options.

Figure: Examples of use of GDRAW

Drawing with hidden line removal and surface fill shading is also possible, but the drawing time may increase substantially for complicated objects.

When using the interactive interface it is possible to cut the object to be drawn with cutting volumes (command CVOL). This is particularly useful to visualise the contents of an object drawn with hidden line removal. Another feature which is available only interactively is the possibility to draw each decendant of a volume shifted along the axis which goes from the centre of the local coordinate system to the centre of gravity of the descendant itself. This again is useful to improve the visibility of the details of a complicated setup (command BOMB). Please see the interactive interface description for more information on this part.

CHNAME

( CHARACTER*4) volume name.

THETA

( REAL) theta angle between the line of sight and the Z axis of MAster Reference System ( MARS).

PHI

( REAL) phi angle between the projection of the line of sight on plane X Y and the X axis of MARS.

PSI

( REAL) psi angle by which the projected image will be rotated on the screen plane.

U0

( REAL) u coordinate on the screen of the volume origin.

V0

( REAL) v coordinate on the screen of the volume origin.

SU

( REAL) scale factor for u coordinates.

SV

( REAL) scale factor for v coordinates.

P.Zanarini, F.Carminati

DRAW115