Using the GeometryBuilder

Multipoint

First, call GeometryBuilder.create_multipoint3(). Use GeometryBuilder.add_point() to add each point of the geometry.

The following example creates a multipoint geometry consisting of three points: (5, 0, 0), (7, 1, 0) and (3, 0, 1).

from GSTPy import GeometryBuilder, RawPoint3

gb = GeometryBuilder()
gb.create_multipoint3()
# point 0
gb.add_point(RawPoint3(5, 0, 0))
# point 1
gb.add_point(RawPoint3(7, 1, 0))
# point 2
gb.add_point(RawPoint3(3, 0, 1))

Multilinestring

First, call GeometryBuilder.create_multiline3(). Use GeometryBuilder.add_point() for each point of the linestring. Finish the linestring by calling GeometryBuilder.new_simplex(). Repeat this for each individual linestring of the multilinestring.

The following example creates a multilinestring geometry consisting of two linestrings as follows:

linestring1: (5, 0, 0) -> (7, 1, 0) -> (3, 0, 1)

linestring2: (2, 0, 0) -> (3, 0, 0)

from GSTPy import GeometryBuilder, RawPoint3

gb = GeometryBuilder()
gb.create_multiline3()
# linestring1 (5, 0, 0) -> (7, 1, 0) -> (3, 0, 1)
gb.add_point(RawPoint3(5, 0, 0))
gb.add_point(RawPoint3(7, 1, 0))
gb.add_point(RawPoint3(3, 0, 1))
gb.new_simplex()
# linestring2 (2, 0, 0) -> (3, 0, 0)
gb.add_point(RawPoint3(2, 0, 0))
gb.add_point(RawPoint3(3, 0, 0))
gb.new_simplex()

Tin

To create a geometry of type Tin3 you can use one of two variants. In both examples we are going to create a geometry with the following two triangles:

triangle1: (5, 0, 0) -> (7, 1, 0) -> (3, 0, 1)

triangle2: (3, 0, 1) -> (7, 1, 0) -> (1, 1, 0)

Variant1

Variant1 is used by calling GeometryBuilder.create_tin3(). Use GeometryBuilder.add_point() 3 times, once for each point of the triangle. After this call GeometryBuilder.new_simplex() to finish the triangle. Repeat this for each individual triangle in the TIN.

Example:

from GSTPy import GeometryBuilder, RawPoint3

gb = GeometryBuilder()
gb.create_tin3()
# triangle1 (5, 0, 0) -> (7, 1, 0) -> (3, 0, 1)
gb.add_point(RawPoint3(5, 0, 0))
gb.add_point(RawPoint3(7, 1, 0))
gb.add_point(RawPoint3(3, 0, 1))
gb.new_simplex()
# triangle2 (3, 0, 1) -> (7, 1, 0) -> (1, 1, 0)
gb.add_point(RawPoint3(3, 0, 1))
gb.add_point(RawPoint3(7, 1, 0))
gb.add_point(RawPoint3(1, 1, 0))
gb.new_simplex()

Variant2

Variant2 is used by calling GeometryBuilder.create_triangle_net3(). Use GeometryBuilder.add_point() to add all the points of your TIN. Afterwards call GeometryBuilder.add_triangle() to create the mesh of the TIN, using the ids from the GeometryBuilder.add_point() calls before.

Note

GeometryBuilder.add_point() returns the id of the added point. This id should be used with GeometryBuilder.add_triangle()

from GSTPy import GeometryBuilder, RawPoint3, IdxTriangle

gb = GeometryBuilder()
gb.create_triangle_net3()

# point 0
v1 = gb.add_point(RawPoint3(5, 0, 0))
# point 1
v2 = gb.add_point(RawPoint3(7, 1, 0))
# point 2
v3 = gb.add_point(RawPoint3(3, 0, 1))
# point 3
v4 = gb.add_point(RawPoint3(1, 1, 0))
# triangle1 (5, 0, 0) -> (7, 1, 0) -> (3, 0, 1)
gb.add_triangle(IdxTriangle(v1, v2, v3))
# triangle2 (3, 0, 1) -> (7, 1, 0) -> (1, 1, 0)
gb.add_triangle(IdxTriangle(v3, v2, v4))

This variant has the adavantage that you can share the same point in multiple triangles. Notice how points (7, 1, 0) and (3, 0, 1) were added only once, instead of twice, as in the example of variant1.

Note

You should always prefer using the second variant if possible, because it will result in a much smaller size of the transferred geometry data.

Tetrahderon Net

To create a geometry of type Multipolygon3 you can use one of two variants. In both examples we are going to create a geometry with the following two tetrahedrons:

tetrahedron1 (5, 0, 0) -> (7, 1, 0) -> (3, 0, 1) -> (4, 4, 0)

tetrahedron2: (3, 0, 1) -> (7, 1, 0) -> (5, 0, 0) -> (1, 1, 0)

Variant1

Variant1 is used by calling GeometryBuilder.create_multi_polygon3(). Use GeometryBuilder.add_point() 4 times, once for each point of the tetrahedron. After this call GeometryBuilder.new_simplex() to finish the tetrahedron. Repeat this for each individual tetrahedron in the tetrahedron net.

from GSTPy import GeometryBuilder, RawPoint3

gb = GeometryBuilder()
gb.create_multi_polygon3()
# tetrahedron1 (5, 0, 0) -> (7, 1, 0) -> (3, 0, 1) -> (4, 4, 0)
gb.add_point(RawPoint3(5, 0, 0))
gb.add_point(RawPoint3(7, 1, 0))
gb.add_point(RawPoint3(3, 0, 1))
gb.add_point(RawPoint3(4, 4, 0))
gb.new_simplex()
# tetrahedron2 (3, 0, 1) -> (7, 1, 0) -> (5, 0, 0) -> (1, 1, 0)
gb.add_point(RawPoint3(3, 0, 1))
gb.add_point(RawPoint3(7, 1, 0))
gb.add_point(RawPoint3(5, 0, 0))
gb.add_point(RawPoint3(1, 1, 0))
gb.new_simplex()

Variant2

Variant2 is used by calling GeometryBuilder.create_tetrahedron_net3(). Use GeometryBuilder.add_point() to add all the points of your tetrahedron net. Afterwards call GeometryBuilder.add_tetrahedron() to create the mesh of the tetrahedron net, using the ids from the GeometryBuilder.add_point() calls before.

Note

GeometryBuilder.add_point() returns the id of the added point. This id should be used with GeometryBuilder.add_tetrahedron()

from GSTPy import GeometryBuilder, RawPoint3, IdxTetrahedron

gb = GeometryBuilder()
gb.create_tetrahedron_net3()
# point 0
v1 = gb.add_point(RawPoint3(5, 0, 0))
# point 1
v2 = gb.add_point(RawPoint3(7, 1, 0))
# point 2
v3 = gb.add_point(RawPoint3(3, 0, 1))
# point 3
v4 = gb.add_point(RawPoint3(4, 4, 0))
# point 4
v5 = gb.add_point(RawPoint3(1, 1, 0))
# tetrahedron1 (5, 0, 0) -> (7, 1, 0) -> (3, 0, 1) -> (4, 4, 0)
gb.add_tetrahedron(IdxTetrahedron(v1, v2, v3, v4))
# tetrahedron2 (3, 0, 1) -> (7, 1, 0) -> (5, 0, 0) -> (1, 1, 0)
gb.add_tetrahedron(IdxTetrahedron(v3, v2, v1, v5))

This variant has the adavantage that you can share the same point in multiple tetrahedrons. Notice how points (7, 1, 0), (3, 0, 1) and were added only once, instead of twice, as in the example of variant1.

Note

You should always prefer using the second variant if possible, because it will result in a much smaller size of the transferred geometry data.

Simplex Properties

In the following we present two variants of how to add simplex property values to a geometry. Other call orders are possible, but these are the most generally useful ones.

Both examples create the same geometry:

Point	gold	silver
(5, 0, 0)	3.0	2.0
(7, 1, 0)	0.5	NULL
(3, 0, 1)	NULL	50.0

Variant1

Here we first add all the points. Afterwards we create the properties and add the property values for each point.

from GSTPy import GeometryBuilder, RawPoint3, PropertyTypes

gb = GeometryBuilder()
gb.create_multipoint3()
# point 0
gb.add_point(RawPoint3(5, 0, 0))
# point 1
gb.add_point(RawPoint3(7, 1, 0))
# point 2
gb.add_point(RawPoint3(3, 0, 1))

gb.create_vertex_property("gold", PropertyTypes.TypeFloat)
gb.create_vertex_property("silver", PropertyTypes.TypeFloat)
# gold for point 0
gb.add_property_value("3.0")
# silver for point 0
gb.add_property_value("2.0")
# gold for point 1
gb.add_property_value("0.5")
# silver for point 1
gb.add_property_null_value()
# gold for point 2
gb.add_property_null_value()
# silver for point 2
gb.add_property_value("50.0")

Variant2

Here we intermix the add_property_value with the add_point calls.

from GSTPy import GeometryBuilder, RawPoint3, PropertyTypes

gb = GeometryBuilder()
gb.create_multipoint3()
gb.create_vertex_property("gold", PropertyTypes.TypeFloat)
gb.create_vertex_property("silver", PropertyTypes.TypeFloat)
# point 0
gb.add_point(RawPoint3(5, 0, 0))
# gold for point 0
gb.add_property_value("3.0")
# silver for point 0
gb.add_property_value("2.0")
# point 1
gb.add_point(RawPoint3(7, 1, 0))
# gold for point 1
gb.add_property_value("0.5")
# silver for point 1
gb.add_property_null_value()
# point 2
gb.add_point(RawPoint3(3, 0, 1))
# gold for point 2
gb.add_property_null_value()
# silver for point 2
gb.add_property_value("50.0")

Notes

The general order for add_property_value is as follows:

With

m the number of properties.

n the number of points.

First call to add_property_value is the value for the first property of the first point.

Second call to add_property_value is the value for the second property of the first point.

[…]

(m - 1)-th call to add_property_value is the value for the last property of the first point.

m-th call to add_property_value is the value for the first property of the second point.

(m + 1)-th call to add_property_value is the value for the second property of the second point.

[…]

repeat n times.

Or in code:

for p in points:
    for prop in properties:
        gb.add_property_value("example_value")