How to create a terrain model for curved slope lot and vicinity?


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I want to create a sufficiently representative 3-D model of the sloped lot for an existing structure and its immediate vicinity. The site is a trapezoid with one rounded side, which rises more less uniformly from the southwest to northeast. The frontage will preserve these contours, while new paved areas will slice through it adjacent to the house and garage. 


The attached sketch shows what I'm trying to do. This assumes that the baseline terrain specification level is 0, then layers & contours are added following the increasing height noted.  


I've tried to construct this using splines for elevation, retaining walls, and terrain breaks. The HD Pro model (attached) is a mess that does peculiar things when I try to add-in more features (I've removed most of that.)  I've looked at the help, docs, and tutorials, tired many hours of experiments, but I can't get much better than this.


I have many specific questions, but the main one is this:

What exactly are the steps to create a model that is stable (doesn't become distorted when I change/add something) and which represents the desired slopes and flat regions?




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17 hours ago, rvbinder said:

The attached sketch shows what I'm trying to do.

Is this sketch plan you have here drawn to scale ?

Can you place a few dimensions on it so it can be modelled?

Thanks in advance.

I'm not a fan of opening random plan files on offer at this forum  - would rather start from scratch on it.


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  • 2 weeks later...

@Robborito:  The sketch is roughly to scale. The upper edge of the terrain boundary is about 200 feet, to allow placement of street, sidewalk, and adjacent buildings. I posted the .plan file as I have been asked by the forum admins to do that in the past. 


The plot boundary (lite green) is 120' at the top (north) side, 95' on the east (right side), 28' on the vertical west edge. The southwest curve has radius ~50'. The south edge is about 95'. The retaining wall at the street is about 2' high at on the northwest gradually increasing to about 4' at the southeast corner. The 0 level of the house is about 7' over the zero level of the terrain. The garage apron should be about 1 foot below this, i.e., about 6' over the zero level. The northeast corner is about 8' over the terrain zero level.


@DavidJPotter: I looked at the videos again, and found a few more clues to this puzzle. I was able to get a terrain model that sufficiently corresponds to my site, although it took a lot of trial and error as all of the tutorials use only rectangles, noting that placing elevation objects inside of the terrain boundary might not work (that's an understatement.) My model starts with two rectangular terrain elevation areas of height zero at the and left and bottom, which extend beyond the terrain boundary. This leaves an undefined triangle at the apex of the curve, as I cannot see how to make a flat elevation area with a curved side. That seems to be producing undulations in the otherwise flat street (6" high) and sidewalk (12" high) that I've drawn over the zero level.


After getting to a close-enough model (street, sidewalk, retaining wall, and curved upslope) I have been trying to model a cut for the 12' wide driveway shown in the sketch. It should start at street level, then climb up to the flat apron area with acceptable transitions and a linear rise (i.e., just following the terrain as shown in the tutorials is not acceptable.) Using a straight retaining wall and a flat terrain region for the apron, I can get the west side of it to look reasonable. However, I cannot get the east side of the driveway to look anything other than bizarre. I tried placing terrain breaks at both the sides of the cut, and drawing in 12' long elevation lines between them corresponding to the top and bottom of driveway elevations. This produces even more weirdness. 


Please provide an example of how you'd model a cut for a linear rise of a driveway with this non-rectangular and sloped terrain.


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  • 1 year later...

Did you ever get an answer to this?  I am trying to do something similar and am finding that retaining walls work reasonably well on a linear slope (with elevation lines that run uniformly vertically OR Horizontally) As soon as I introduce any angle across the terrain to the elevation lines retaining walls just stop working and become some kind of weird stub  wall that follows the terrain contour and does nothing to "retain" anything :(

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