# HC Card

The HC card creates a cylinder with a hyperbolic border.

On the Construct tab, in the Surfaces group, click the  Hyperbolic cylinder (HC) icon.

## Parameters:

S1
The origin (where the asymptotes intersect) of the hyperbolic border.
S2
The pole of the hyperbolic border.
S3
The point where the hyperbolic arc and the straight edge intersect.
S4
The pole of the hyperbolic border at the opposite edge of the cylinder.
Normal vector directed
The normal vectors is directed inward or outward.
Max. triangle edge length (at hyperbolic border)
The maximum edge length on the hyperbolic border.
The hyperbolic border may require shorter mesh edges than those used for straight edges. Thus the maximum segment length specified in the IP card may be overridden along the arc by setting Max. triangle edge length (at hyperbolic border).

## Example of HC card usage

The cylinder with a hyperbolic border shown in Figure 2 is created using the HC card.