I need to model a complex profile with gradient.
From the top view, the alignment line have various curves and its not straight. From the side view, the alignment line is straight and sloping downwards at 2% gradient. The percentage doesn't matter the key question here is the sloping downwards while maintaining the top view profile.
For illustration purpose, i made a comparison showing what happen when its a straight line with gradient.
What you're after is a helix. use the helix tool to define your path, but you'd need to work out hard numbers for the top radius, base radius and the pitch which relates to your gradient.
it is not actually a helix. i simply draw it for easier understanding of the question and clearer illustration. In the actual drainage project i am working on, i have various lines of different curvature. The pipes or the scupper drain need to slope down at 2% gradient constantly so that the water can flow from higher point to lower point.
can u show an example of how you do this?
if you can post a sample of the alignment string I'll try to have a go.
Bentley Question 2.dgn
sure. here is a sample of the alignment line extracted from the file
Here you go.
Bentley Question 2_helix.dgn
can u describe how this is done?
each horizontal curve (Ch) corresponds to a helix.
Helix radius = Ch radius
Helix height = Ch radius * Ch sweeping angle (in radians) * gradient
Helix pitch = Ch radius * 2 * Pi * gradient
Answer Verified By: Kang Teng Teng