AutoCAD Civil 3D

[#1]

I'm doing a small design for a footway/cycleway across an embankment behind an existing retaining wall with a tie-in to an existing car park.

• H-alignment done (LHS edge alignment, chainages working from west to east)
• H-alignment target extents to retaining wall
• V-alignment done, with target to RHS offset design levels beyond crest and into car park
• Combined surface created by pasting existing ground and finished top surface (shown in contours).
• Some anomalies corrected by swapping edges in the EG surface.

As can be seen, I appear to be missing triangles from the design corridor.

I'd be very grateful for any advice about what I should experiment with in order to improve the corridor model. This will improve the accuracy of the earthworks calculations. Thanks in advance.

[#2]

Thats some frequency

Have you verified all targets for all regions?

[#3]

It looks like you might have a boundary problem that is causing triangles to be deleted.  How is the surface boundary defined?

[#4]

Thanks for the swift replies.

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Joe-Bouza wrote:

Thats some frequency

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Thanks, yes, I could reduce the frequency, but it's only 50m long and I wasn't confident with the 1m frequency. I really need to compare surfaces for different frequencies (probably finished contours would do it).

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Have you verified all targets for all regions?

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Yes, but I've not removed all the region definitions and retargeted from scratch. I'm not sure if it's correctly designed or not. Maybe these further screengrabs will be informative.

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sboon wrote:

It looks like you might have a boundary problem that is causing triangles to be deleted.  How is the surface boundary defined?

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The surface is created from the corridor, with no additional edit operations listed in the surface properties.

(The remaining Edit operations are Yes, except 'Use simplify'.) Some of the missing triangles cross region boundaries, but some are within single regions, with correct triangles either side running to the start/finish of the region(s).

[#5]

Do you have any more pointers on this, please? Thanks.

[#6 · Accepted solution]

To clarify my original question.  Is the surface boundary defined in the corridor by polygon, by featurelines or by corridor shrinkwrap?

[#7]

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sboon wrote:

To clarify my original question.  Is the surface boundary defined in the corridor by polygon, by featurelines or by corridor shrinkwrap?

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The boundary was undefined! I've added it as corridor shrinkwrap and it now seems to be sorted! Thanks so much