Create Isoparametric Curve On a Face

Synopsis

obj = ISOCRV/obj{,UDIR|VDIR},num1[,TOLER,num2][,CNT,num3][,IFERR,label:]

Description

Creates an isoparametric curve at given parametric values (u,v) on a face. The minor words UDIR and VDIR represent the (u,v) parametric values.

NOTE:The resulting isoparametric curve is not a "smart" curve. In other words, it is not associative to the face from which it is created. If the face is modified, the curve does not change.

NOTE: You cannot create isoparameter curves of constant v from a blend.

Parameters

Parameter

Description

ISOCRV

Major word specifies the creation of an isoparametric curve.

obj

The face object identifier on which the curve is created.

UDIR

Minor word indicates that the isoparametric curve is to have a constant u parameter.

VDIR

Minor word indicates that the isoparametric curve is to have a constant v parameter.

num1

The parameter value at which to create the curve. This value must be greater than 0.0, less than 1.0.

TOLER

Optional minor word specifies the use of a tolerance value. The tolerance is only used when the input face is a foreign face or an offset of a non-analytic face.

num2

The tolerance value. This value must be greater than 0.0.

CNT

Optional minor word indicates the number of curves created is reported to the calling program. You may only get multiple curves if the face is trimmed.

num 3

The number of curves created.

IFERR,label:

Specifies a label to which program execution jumps if an error occurs.

Example

Creating a B-surface type sheet body, then use the ISOCRV statement to create two isoparametric curves, one in each direction.

 
   ENTITY/BS,CRVS(10),PT
   NUMBER/SPAR,CRVCT
   $$
   $$ Create a b-surface for use in isoparameter curve creation.
   $$
   &ENTCLR = &GREEN
   $$
   CRVS(1) = LINE/4.0,0.0,4.0,0.0,0.0,4.0
   PT = POINT/2.0,0.0,0.0
   CRVS(2) = CIRCLE/CENTER,PT,RADIUS,2.0,START,0.0,END,180.0
   $$
     BS = BSURF/CURVE,CRVS(1..2)
   $$
   $$ We always create a curve at parameter 0.5.
   $$
     SPAR = 0.5
   $$
   $$ Create constant U curve.
   $$
   &ENTCLR = &CYAN
   $$
   CRVS = ISOCRV/BS,UDIR,SPAR,TOLER,0.001,CNT,CRVCT,IFERR,ERR:
   $$
   $$ Create constant V curve.
   $$
   &ENTCLR = &YELLOW
   $$
   CRVS = ISOCRV/BS,VDIR,SPAR,TOLER,0.001,CNT,CRVCT,IFERR,ERR:
   $$
   JUMP/LEND:
   $$
   ERR:
     MESSG/'CREATION ERROR'
   $$
   LEND:
     HALT

Parameter	Description
ISOCRV	Major word specifies the creation of an isoparametric curve.
obj	The face object identifier on which the curve is created.
UDIR	Minor word indicates that the isoparametric curve is to have a constant u parameter.
VDIR	Minor word indicates that the isoparametric curve is to have a constant v parameter.
num1	The parameter value at which to create the curve. This value must be greater than 0.0, less than 1.0.
TOLER	Optional minor word specifies the use of a tolerance value. The tolerance is only used when the input face is a foreign face or an offset of a non-analytic face.
num2	The tolerance value. This value must be greater than 0.0.
CNT	Optional minor word indicates the number of curves created is reported to the calling program. You may only get multiple curves if the face is trimmed.
num 3	The number of curves created.
IFERR,label:	Specifies a label to which program execution jumps if an error occurs.