Grading Problem, with pictures.

[GreeneSWCD]

I have a problem getting a grading to work on two perpendicular earthen berms.  There is a main berm that is 20' tall, and another berm that meets this berm at a right angle that is only 10' high.  Both Berms have the same side slopes and top width. 

I've tried to methods.  The first thing I did was draw a feature line in an 'L' and then set the elevations at all the corners, including the slop from the tall berm down to the connection point of the short berm.  Well, that should have worked, but then my corners had funky triangles that I couldnt' get worked out.  And, these got even worse when I did an infill on the topwidth. 

The second thing I tried was to get around the funky triangles.  I put the short berm into its own site and surface and then created a merged surface with the tall berm and the short berm surfaces pasted in.  I thought this would work, but there isn't any blending between the two surfaces.  See pictures. 

What's the best way to do this?

[ericcollins6932]

I'd recommend filleting those L corners just a little and connect the two berms. Looks like you have them as separate features right now. Or build one berm in one site and build the second berm targetting the first for daylight.

[GreeneSWCD]

Gotcha, I'll try it.

[GreeneSWCD]

I've filleted that inside corner, but I have a new problem now.  I can't get the feature line to grade down to the existing surface now.  It acts like I put a vertex on my feature line at 0 elevation, but a 0 elevation vertex isn't listed in the elevation dialog box of the feature line any where. 

I'll attach a pic of the infill inside of the new filleted feature line.  It's a 10' radius. 

If it helps, this is a rifle range restoration for a local police deparment.  The main berm is at 1085' and it needs to go to 1094'.  Then a new side berm on the range needs to be installed perpendicular to it at 1081'.  The existing ground is about 1071'. 

[GreeneSWCD]

Wait, I see you added a little to your response.

If I use the first berm for a target to daylight the other berm, how do I also use the existing ground to daylight the rest of the berm that doesn't touch the main berm? I didn't know I could use two daylight targets for one feature? Or am I misunderstanding you?

[Neilw_05 · Accepted solution]

My approach is to use separate berm surfaces.

1) Model the taller berm first (Berm 1). Make an intermediate surface by pasting the EG first then the tall berm surface.

2) Model the lower berm (Berm 2) and target the intermediate surface above. The intersection should blend perfectly.

3) Create the final surface by pasting EG, Berm1 and Berm 2.

[GreeneSWCD]

That could be good! Here I go...

[Neilw_05]

I am revising the workflow. It will work better if you model the lower berm first. That way you won't have to be precise with making the lower berm fit the taller berm. Just make the lower berm encroach the taller berm enough for the taller berm to intersect it entirely. When you paste the surfaces the overlap will get wiped out and you'll have a perfect intersection.

Be aware that you'll need to use different sites for each berm so they don't interact with each other.

[Neilw_05]

Here is a screen recording showing the gradings and the results.

http://screencast.com/t/8PQwtnYw1TJ6

[GreeneSWCD]

Neil, I got to work on something else for the rest of the day, but I'll get back to this in the morning!  Actually, can't wait to try your suggestion.  The video is very easy to follow! 

While we are at it, I'm getting these frustrating corner holes in my surface gradings.  How do I get triangles in the TIN up in those corners?  Here's pictures:

[Neilw_05]

It's hard to diagnose the problem without knowing how you created the gradings. I assume you have applied an infill to the enclosed area. Somehow you have ended up with additional areas that need infills. How that came about is the unknown. If you want to post a drawing I can take a look at it. 

[GreeneSWCD]

I can tell you how I did that pretty easily.

I drew a feature line up the center with one end on the surface and the other end on a 1% grade. Then I drew box around it grading all the corners into that line. I then took the box line and the center line and applied them to a new surface. Then put an infill in it, and that infill didn't get to the corners.

Oh, I filleted the corners of the box before infilling, hoping that would keep tha from happening. 😉

[Neilw_05]

It may be a workflow issue. Typically you create a surface from the gradings by toggling on the Create Surface option for the grading group. The infills should make the enclosed area part of the grading surface so you would not need to add the longitudinal and perimeter featurelines as breaklines to the surface. In fact C3D would not allow you to add them since they are already included from the grading. That tells me your surface is not built from the grading. Again I'd have to see your drawing to diagnose it.