Help me correct this proposed TIN / Surface

[Chaznsc]

Using a mixture of polylines, featurelines, corridors to make a surface. Every so often I end up with these mitered contours where they should be at right angles. I see the irregulatity causing them, just not sure what to do about it. 

See image below:

[tcorey]

Polyline Contour or Feature Line, you say. How do we know the feature line elevations aren't such that the contour needs to cut the corner to be accurate.

As a general rule, decreasing the size of your supplementing factor will help. This will add TIN Points, making the surface seem less blocky.

[stevenh0616]

Hi @Chaznsc 

To answer the question of why this is happening, you need to review how all the settings work when Adding Contour data to your surface. I believe the option you need to turn on for this is Swapping Edges.

https://help.autodesk.com/view/CIV3D/2024/ENU/index.html?guid=GUID-6DDF0736-9174-4F05-9D7B-5A60E68D4...

However, with that said, it appears you are just adding contours to the surface instead of using breaklines to define your surface. Why?

The best way to grade a surface in Civil 3d is to define where the grade breaks are using Feature Lines and add those to the surface, then let Civil 3D draw the contours. Yes, there are a few situations in that it's helpful to add some contours - but in most scenarios, you get a much better surface when you actually use breaklines. If you profile two different surfaces built in these methods, you'll see the difference when you cut a profile through the surfaces.

Here's an example of where you should have some breaklines in blue:

[Chaznsc]

Thank you borth for rthe replies. Im still learning with every project. Another brick in my wall today. 

[stevenh0616 · Accepted solution]

I was able to replicate.

Swapping Edges = False

Swapping Edges = True

[stevenh0616]

Great to hear that @Chaznsc.

Keep going - but I would try to get away from mindset of drawing contours. With break lines, you'll have more control defining the critical points of your design and when it comes to making edits, you're adjusting slopes/elevations instead of contour spacing. Civil 3D will do all that for you, if you allow it.

[Chaznsc]

Since you asked 🙂 ............... I start with a profile --> Corridor --> Feature line --> Surface. Then I level off the lots using polylines added to the previous finished surface. The lots we develop are slab on grade, so we need a level pad on each lot. This is where the real struggle begins. And if the centerline changes, well, its a lot of rework. 

See below:

[stevenh0616]

Makes sense. Might want to take a look at my Lot Grading Tools

https://apps.autodesk.com/CIV3D/en/Detail/Index?id=6076719345115153828&appLang=en&os=Win64

[Chaznsc]

That looks like a nice application. Unfortunately, a company our size wouldnt purchase it without some kind of proof on return. That said, I frankly wish Autodesk would focus on this sort of thing rather than churning out releases of "more of the same" every year. 

Thanks for your help and willingness to listen.