# ZY Card

This card defines a surface mesh in the form of a cylindrical segment.

On the Construct tab, in the Surfaces group, click the Cylinder icon. From the drop-down list, click the Cylinder (ZY) icon.

## Parameters:

- S1
- The start point of the axis.
- S2
- The end point of the axis.
- S3
- A point on the corner of the cylindrical segment.
- Normal vector directed
- The triangles can be created so that the normal vector is points Outward or Inward.
- The angle $\phi $ (degrees)
- The angle in degrees, which is subtended by the cylindrical arc.
- Maximum edge length on arc
- Maximum edge length of the triangles along the curved side in m (is scaled by the SF card). If this parameter is left empty, the value specified with the IP card is used.
- Scale second half axis with
- If this parameter is empty or is set to 1 , a circular cylinder is created. If set to
$\frac{b}{a}$
, an elliptical cylinder is created. Here
$\frac{b}{a}$
gives the ratio of the two half axes, where a is the
distance S
_{1}–S_{3}. It is not recommended to generate elliptical cylinders with extremely small or extremely large axial ratios with a CAD system as the distortion formulation used in PREFEKO may fail in these cases.

_{1}–S

_{2}and S

_{1}–S

_{3}are perpendicular), the segmented area (shaded in the figure of the cylinder) is obtained by rotating the point S

_{3}around the axis S

_{1}–S

_{2}through $\phi $ . For $\phi =360\xb0$ a full cylinder is created.

An oblique cylinder (that is the
circular or elliptical rim is not perpendicular to the axis) can also be created. Then
S_{1}–S_{2} still represents the axis, but the top and bottom planes of
the rims are defined by planes perpendicular to the plane defined by the three points
S_{1}, S_{2}, S_{3}, and parallel to the line
S_{1}–S_{3}.

## Examples of ZY card usage:

The cylindrical section below was created with a single ZY card.```
**
IP: : : : : : : 0.4
DP: A : : : : : 0.0 : 0.0 : 0.0
DP: B : : : : : 0.0 : 0.0 : 2.0
DP: C : : : : : 1.0 : 0.0 : 0.0
ZY: A : B : C : : : 180.0 : 0.35
EG: 1 : 0 : 0 : : : : : : : : : : 1
EN
```

The elliptical cylinder below was created with a single ZY card.

```
** Example for an elliptical cylinder
** General parameters
#a=1.5 ** first half axis of the elliptical cylinder
#b=2.5 ** second half axis of the elliptical cylinder
#h=4 ** height of the cylinder
** Segmentation
#kanl=0.4
IP: : : : : : : #kanl
** Define points
DP: A : : : : : 0 : 0 : 0
DP: B : : : : : 0 : 0 : #h/2
DP: C : : : : : #a : 0 : 0
** Define the geometry
ZY: A : B : C : : : 90 : #kanl : #b/#a
** End
EG: 1 : 0 : 0 : : : : : : : : : : 1
EN
```

The non-orthogonal cylinder below was created with a single ZY card.

```
** Example for a non-orthogonal elliptical cylinder
IP: : : : : : : 0.3
DP: A : : : : : 0.0 : 0.0 : 0.0
DP: B : : : : : 0.7 : 0.0 : 1.0
DP: C : : : : : 1.0 : 0.0 : 0.0
ZY: A : B : C : : : 360.0 : : 1.5
EG: 1 : 0 : 0 : : : : : : : : : : 1
EN
```