The TrimmedCurve declaration can be used to reparametrize an edge of a shape to shorten or extend it. To use it either set the shape to the edge you want to reparametrize or embed another curve within the node. Then set the new u and v values for the start and end parameters.

Note: The current parameters of a curve can be obtained by using Topology(shape=edge).curve_bounds which returns the min and max of the curve.

# Created in DeclaraCAD
from declaracad.parts.display import Axis
from declaracad.occ.api import *

enamldef Assembly(Part):
    Axis:
        pass
    Box: segment:
        transparency = 0.8
        dx = 10
        dy = 5
        dz = 3
    TrimmedCurve:
        color = 'red'
        u = -10
        v = 10
        shape = segment.topology.edges[1]
    TopoShape:
        color = 'blue'
        shape = segment.topology.edges[1]

Reparametized curve