Good Morning,
I am having an issue with a corridor model. The alignment has several turns in it and if you try to use a vertical alignment to transfer elevations to a 2D line inside of the job, the surface will overlap itself because it is attempting to assign grades from different parts of the alignment. Is there a way to stop this from happening?
What do mean by “transfer elevations to a 2D line”? Post a screenshot.
It was a rough way of saying to create a vertical alignment and then use “offset/elevation” to bring the elevations to a 2D line by selecting the 2D line as the offset and delta elevation of 0 using the vertical alignment as the node to offset from. If you don’t select it as a finish feature it’s fine but I need to continue building further out from this line. When I try to build out to another line, the surface tries to connect with other parts of the lines thousands of feet apart from each other seemingly because they are in line with each other due to the alignment being “C” shaped.
It’s hard to understand exactly what you are saying. It’d be best to share the file if possible. But the one thing you can try is to decrease the maximum offset values in the templates properties. Also decreasing the maximum edge length of the corridor surface.
Hey Adam,
It sounds like you are having issues with your Corridor Alignment geometry. I would edit your alignment and look for Non-tangent bearing deflection in the Horizontal Geometry. This would be where your Bearings/Azimuths are changing outside of a curve. This can also happen if you have taken a 2d Cad line that has corded curves and converted it to an alignment.
If you are transferring alignment information from CAD to TBC it is best to use an LandXML format to preserve the curvilinear nature of your alignment. If this is not an option I would recommend building your alignments by hand from the alignment data in your projects plans.
Let me know if this helps you.
In these images you can see the issue. All I have done is connect 7 to 10. It should just produce a flat bottom between the two lines. Instead, it is carrying the surface across to other parts of the surface. I have to build it this way because I need to ensure that the bottom of the canal elevation is correct and the elevations on the top of the levee are correct. There will be a 3.3:1 from 7 to the East for 10.5’ and then I need to connect that point and 8. That slope will vary based on the canal bottom and the top of the levee. I’ve had success doing this in the past but there seems to be an issue with it this time.
It built out the top of the levee just fine, but when I connect these lines this issue occurs.
Try doing what Modelmysite said
“It’s hard to understand exactly what you are saying. It’d be best to share the file if possible. But the one thing you can try is to decrease the maximum offset values in the templates properties. Also decreasing the maximum edge length of the corridor surface.”
It’s under the properties of the template.
That fixed it. Thanks guys.
The problem you are seeing is typical of alignments that create ambiguity because of their shape, ie when you have a right angle corner like you do here, a point on the inside of the corner can be at two different stations on the alignment so which one is correct from an automation standpoint.
The limit of the offset stops the corridor looking too far for the station for a point so that reduces the ambiguity - see the post / Video on modeling Horseshoe Roads - this is where we see the biggest problems where an alignment loops back on itself entirely - there are a few settings that help to control that
Click Here for the link to the post on Horseshoe Roads
