Cylinder#
A cylinder is a truncated cone whose apex is at infinite distance. So it is the geometry defined by the extrusion of a surface by translation.
To construct a Cylinder geometry, use parameters _basis and _direction. _basis parameters, as for trunks, take any surface object: Polygon,
Triangle, Quadrangle, Parallelogram, Rectangle, SquareGeo, Ellipse or
Disk. _direction parameter takes a vector of real numbers (Point or Reals objects) or a single value (in this case, it is like a direction parallel to x-axis).
As for a trunk, a cylinder with elliptical basis can be defined by another way, using parameters _center1, _v1, _v2 and _center2, taking a point or a single value (in this case, it is like a 1D point). _center1,
_v1 and _v2 parameters are used as for a Ellipse or Disk object (see Ellipse or Disk for details). _center2 parameter is used in this case instead of _direction parameter,
as it is easier to give the center of the second basis, instead of the direction vector.
_nnodes can take one single value, an explicit list of 3 or \(n\) values or a Numbers object, where \(n\) is 3 times the number of edges of the basis. _hsteps can take one real value,
an explicit list of \(p\) real values or a Reals object, where \(p\) is the number of points defining the trunk. If required, give names of main domain and side domains as explained in Geometry definition:
Cylinder c1(_basis=Disk(_center=Point(0.,0.,0.), _v1=Point(2.,0.,0.), _v2=Point(0.,2.,0.)), _direction=Point(0.,2.,1.), _nnodes={10,10,10,10,5,5,5,5,20,20,20,20}, _domain_name="Omg",_side_names={"Gam","Gam","Sig","Sig","Sig","Sig"});
Cylinder c2(_basis=Disk(_center=Point(0.,0.,0.), _v1=Point(2.,0.,0.), _v2=Point(0.,2.,0.)), _direction=Point(0.,2.,1.), _scale=0.5, _nnodes={10,5,20}, _domain_name="Omg",_side_names={"Gam","Gam","Sig","Sig","Sig","Sig"});
Cylinder c3(_center1=Point(0.,0.,0.), _v1=Point(2.,0.,0.), _v2=Point(0.,2.,0.), _center2=Point(0.,2.,1.), _scale=0.5, _nnodes={10, 5, 20}, _domain_name="Omg", _side_names={"Gam","Gam","Sig","Sig","Sig","Sig"});
These are 3 definitions of the same Cylinder object, explaining the ability to give 3 values for _nnodes , instead of 12.
Let’s summarize information about geometrical keys on cylinders:
key(s) |
authorized types |
examples |
|---|---|---|
|
|
|
|
|
|
|
|