Help With Terrain - Walkway beside top of retaining wall - Slope required and chief can only do flat sections


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Hi everyone,


I am stuck on a tricky terrain issue. I am designing a multi family building site that has some relatively simple grading required for the parking lot and pedestrian access which chief cannot seem to accurately process. Perhaps I am missing a trick? I have uploaded the relevant portion of my plan so you can take a look.


Basically I have a pedestrian access "sidewalk" coming on the property at a higher elevation, and a driveway leading to a parking lot at a lower elevation. The driveway and parking lot all have carefully calculated grades leading to the elevation I have set as top of parking slab (2159.00 ft). After days of messing with the retaining walls and terrain breaks I finally got the parking lot to work. Now the problem is that chief cannot seem to handle terrain topographic lines intersecting the top of a retaining wall / terrain break without creating absolutely batshit crazy peaks and valleys everywhere. Since the site requires that I have a sidewalk pedestrian access at the top of one of these retaining walls with a maximum slope of 2%, these crazy variations are screwing up my plan. I cannot seem to get rid of them except with flat terrain areas, which of course screw up the pedestrian access elevations. I can't just cheat and do stairs because this building needs to be handicap accessible. Chief cannot do terrain area's with a slope... something they should absolutely add!!!!!

How do I fix this problem?


I would really appreciate some help here as I have spent the last few days really struggling with the terrain features of chief and I am at my wits end trying to figure out this issue.




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Hello Whistler,


I made a few improvements to your plan and I know that there are issues with terrain in chief but you have a lot of overlapping data and the software does not deal with that kindly.  Stuff that you might tell your landscaper and he would just make it work out, chief does exactly what you tell it no questions asked.


You need less data and more separation between features.  As for the sloped sidewalks it seems you will need something other than a straight ramp for the elevation difference that exists.   I would have a tendency to use more slabs and ramps for things that have fixed elevations and paths for more general terrain following walkways then work the terrain to these features.


I could post the plan for you but I think we could accomplish more with a short Skype session so PM your skype name if you are interested.  Sort of need to know what is just for looks and what you got from your surveyor the can't be changed.

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My best pieces of advice when creating terrains are:

Wherever possible use Terrain Elevation Lines/Splines instead of Elevation Points.

Avoid using Elevation Points in the same are as Elevation Lines/Splines. 

Use Terrain Breaks with normal walls where you want a vertical retaining wall.

Avoid Linear Terrain Surface Smoothing - in this case, you need to reduce your terrain elevation and rationalise it as Chopsaw said, to reduce conflicts.

Use Elevation Regions wherever possible for flat areas and let Chief auto grade the terrain between the Elevation Regions.


You also need to be aware that some landscaping tools like the Straight Road tool will actually influence the shape of the terrain. In the case of the Straight Road, Chief will automatically cut and fill the terrain to result in a road which is level in cross section.

So if you want your parking area to follow your terrain levels, you may be better of by not using the Road tool, but using a Terrain Feature instead.

Another thing is to ignore the name of the tool and learn what it really does instead of assuming it performs a certaain function because of it's name.


There are many little things like this that you need to be aware of when dealing with terrains.


This is a picture of a project I am working on at the moment - plenty of retaining walls, level and sloped areas.

I will have a deeper look at your plan and see exactly what is happening and where the major areas for improvement could be. 

New Image_69.jpg


This is what a road does automatically to the terrain.




I have just had a quick look at your terrain and the first thing that stands out (apart from your use of spot levels and Roads, is that your Elevation Lines have WAYYYY to many segments.

Each segment node is really a terrain point.

How did you draw those Elevation Splines  - my guess is that you converted them from some other type of entity.


You Elevation Splines are at 12" intervals - do you really need them that close together - over the whole site?


I will keep looking.

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Hi Glenn,

I am aware of much of what you said. However, I always welcome help when I am stuck here so thank you very much for your reply. As I mentioned in my post my problem is very specific. The sidewalk at the top of the retaining wall goes absolutely crazy unless I have a flat terrain area specified, which is a problem because I need the sidewalk to slope down to a point then back up again to the entrance of the building.


This is a very specific problem with terrain breaks and retaining walls.


That said, I have always had a problem getting chief to make terrain breaks work properly.

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To get down to basics, it really isn't such a specific problem as you say - it has to do with the whole terrain and the information you have used.

The fact that you have so much elevation data in the plan is only allowing Chief to process the information as Linear.

Reduce the amount of elevation data and you will be able to choose one of the other Terrain Surface Smoothing options.


As far as the retaining walls go, I repeat - do not use Terrain Retaining Walls - use a Terrain Break with a normal wall, slab, polysolid, etc. 

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Hi Glenn,


I tried to follow your advice with the terrain retaining walls vs normal walls, and using terrain breaks. I am still getting the same problem that I had originally of terrain lines and elevation data bleeding through the terrain break to effect elevations and terrain lines on the other side of it.

The terrain elevation lines I am using are from a topographic survey of the area. I need the accuracy on most of it and have no way of reducing the spline calculations. Apparently chief just cannot process the amount of information supplied in a regular survey document. This is disappointing!

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Once again, you need to reduce the amount of elevation data - even if you have to copy over the imported contours (I'm sure you could leave out at least every second elevation line) and the get same or even a better result - sometimes less is more.

You also need to rationalise the amount of conflicting elevation data.

At the retaining wall on the side of the carpark, you have Elevation Points, a Retaining Wall, a Terrain Break, an Elevation Region.....all in the same place!

What is Chief meant to do with all this conflicting information?

Most importantly, you need to be able to select a Terrain Surface Smoothing other than Linear as that means no surface smoothing - Chief will just join the elevation points with straight lines - not what you want.


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The terrain points and elevation region in the same place were a half finished project. The points were part of a grade calculation, and the terrain region was a quick cheat to correct the horrendous peak/valley problem you get without terrain regions. It was basically a quick fix to export an image to my boss to show the basic look of the area after changes to the parking.


Reducing the terrain lines from the survey is an interesting idea, also manually drawing over them with less points. It does not sound time efficient unfortunately. I wish chief could handle more data with its terrain calculations. Sketchup seems to do a much better job of this.

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give this a try i cleaned the terrain up so that you do not have elevation data fighting i have changed a few things to make it easy for me to clean up the terrain it should either give you some ideas or get you moving in the right direction i hope terrains are tricky thing to do 


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Mark 3D. Thank you for the suggestions!

The main trick of making the parking lot as a room absolutely clears up all the problems generated by the elevation change on either side of the surrounding retaining walls. This makes the walkways actually work properly with the use of evenly spaced terrain lines. I had tried them before and it was just a mess.


This seems to be one of the best solutions so far. Unfortunately it has the issue of not being accurate when it comes to the final construction set of plans because the "room" has a flat floor elevation. This looks nice and clean, but when you need to set drain heights, parking lot gradients for drainage, and sub surface pipe elevations etc this information will all be missing. I suppose you could have it as a layer that is just the text information instead of trying to get chief to accurately do it in 3d. In my last project we did this whole system in sketchup so that our site super could show all our workers exactly where each pipe and drain element went on the site in 3D in the site office. Something that was well worth the time to setup. I just wish I could do this within chief instead of having to use two different softwares and re draw everything.

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