ZY Card

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 $φ$ (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 S₁–S₃. 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.

For an orthogonal cylinder (that is the lines S₁–S₂ and S₁–S₃ are perpendicular), the segmented area (shaded in the figure of the cylinder) is obtained by rotating the point S₃ around the axis S₁–S₂ through

φ

. For

φ = 360 °

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 S₁–S₂ 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 S₁, S₂, S₃, and parallel to the line S₁–S₃.

Examples of ZY card usage:

The cylindrical section below was created with a single ZY card.

Figure 2. Example of a cylindrical section using the 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.

Figure 3. Example of an elliptical cylinder using the 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.

Figure 4. Example of an non-orthogonal cylinder created with the 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