GeoMax Zoom20 Pro Series - Page 71

Applications Zoom20/30/35 Pro | 71
Vertical geometry
elements
For onboard input Road 3D supports the following elements for vertical alignments.
Spiral types • Entry spiral (Spiral in = A): Spiral with a radius of infinity at the start and a given
radius at the end.
• Exit spiral (Spiral out = B): Spiral with a given radius at the start and radius of infinity
at the end.
• Partial/Ovoid spiral: A spiral with a given radius at the start and another given radius
at the end.
AEntry spiral
BExit spiral
Element Description
TSOX_112
A
B
Element Description
Straight A straight has to be defined by:
• Start chainage and start height of P1.
• End chainage and end height of P2, or length (L) and slope (%).
P1 Start point
P2 End point
LLength
%Slope
Transition
curve
A circular curve has to be defined by:
• Start chainage and start height of P1.
• End chainage and end height of P2.
• Radius (R).
• Type: Convex (crest) or Concave (sag).
aConvex
bConcave
P1 Start point
P2 End point
RRadius
Quadratic
parabola
A quadratic parabola has the advantage that the rate of change of grade is constant,
resulting in a "smoother" curve. A quadratic parabola has to be defined by:
• Start chainage and start height of P1.
• End chainage and end height of P2.
• Parameter, or Length (L), grade of entry straight (Grade In) and grade of exit straight
(Grade Out).
P1 Start point
P2 End point
LLength
%Slope
TSOX_113
P2
P1
P1
-%
L
P2
+%
L
TSOX_051
P1
R
a
R
P2
P1
RR
P2
b
TSOX_114
P1
+%
-%
P2
L
TSOX_115
+%
-%
P1
P2
L