Elevation / Terrain doozy

[JoeinNorCal]

Hi all.  I picked a challenge for my first CA project, a very complex remodel.  I am the owner, working closely with a contractor.  I'm in Phase 3, seeking a permit to excavate a garage into a hillside, the roof of which will be a front yard.  There are existing stairs (public) that go up the hill adjacent to my property, as shown.

 

I've looked at terrain in help, watched videos, etc., and I'm getting there, with combination of foundation walls, terrain breaks, stairs, elevations regions, points, etc, but this is a GRIND for me.  I'm trying to get the terrain between the garage and the stairs to be a few inches ABOVE the height of the garage roof.  The garage roof will actually be artificial grass.

 

1.  Are there PARTICULAR videos or help topics that you can suggest to move me along at 20 mph, rather than just 5 mph?

2.  Similar question about elevations for house floors and terrain.  Floor 1 starts at 0", but elevations are absolute to sea level.  Ugh.  In my plan, they seem out of sync.  Street at front of upslope site is 98 feet above sea level.  Chief is showing it at -41 feet.  My first floor, at 0", is about 20 feet above the street, or 120' above sea level.  How do calibrate terrain to sea level?

 

Thanks,

[robdyck]

4 minutes ago, JoeinNorCal said:

My first floor, at 0", is about 20 feet above the street, or 120' above sea level.  How do calibrate terrain to sea level?

All terrain elevation data is relative to the elevation of the TERRAIN PERIMETER. You can enter all terrain elevations using the correct geodetic data. You THEN adjust the elevation of the TERRAIN PERIMETER relative to the main floor. Just like surveying...up is down and down is up! That is to say that a larger positive number here (screenshot) will lower the terrain relative to the structure and a smaller, or negative number will raise the terrain.

[JoeinNorCal]

Thanks Robert.  Perimeter has no elevation associated with it, per help.  So I put an elevation line in at the entrance to the first floor.  To have the ground be at Floor 1 = 0", I had to make the ground elevation be -280".  Then I created other elevation data above and below that to build my slope. The result is that Chief is telling me that the front of my lot is 32' below sea, when in reality, it is 98' above sea level.  ???

[robdyck]

27 minutes ago, JoeinNorCal said:

To have the ground be at Floor 1 = 0", I had to make the ground elevation be -280

To clarify Joe, there is no "Ground Elevation" in Chief. For terrain elevations there are:

• points
• lines
• splines
• regions
• breaks ...and
• Subfloor Height Above Terrain

Perhaps when you say 'ground elevation' you are referring to one of the above terrain elevation tools?

 

My point was simply this...You can initially model your terrain to match real world conditions without any regard for the building. Then, using "Subfloor Height Above Terrain", you can adjust the entire terrain up or down to your liking. Once it's close to your desired elevation, then its a good time to make the necessary adjustments to the elevations as it relates to the structure. It can also be handy to make a symbol of your modeled terrain and place it on its own layer as a point of reference.

 

By contrast, if you have started to model your terrain, and somewhere along the way started modifying elevations based on the structure, it will get out of whack quickly. It's also helpful to create a hierarchy of interior lot elevation requirements to help with prioritizing the modification of the interior portions of the terrain. Often the grading percentage of the driveway to the street is the #1 requirement....

[JoeinNorCal]

8 minutes ago, robdyck said:

By contrast, if you have started to model your terrain, and somewhere along the way started modifying elevations based on the structure, it will get out of whack quickly.

 

By your accurate description, I am whacky.  But you have provided me with a map.  Thanks.

 

And yes, by "ground elevation" I meant the level of the terrain in my model, as set by a line, at the entrance to Floor 1.

[parkwest]

I like this one the best...

 

 

[JoeinNorCal]

Hi David!  I'm getting closer....  Have spend shelter in place watching a lot of videos and reading a lot of Chief help pop-ups.  I'm much improved.  Still, Chief can be frustrating.  But not nearly as bad as the local planning department...

[Charles]

I agree manipulating terrains in Chief is frustrating! 

Here in Hawaii, we have challenging mountainous regions and I wish they would use a terrain mesh that could be directly manipulated rather than all the workarounds we have to endure......

[KimHist]

I am newbie too, but my solution for terrain was to set the lowest point above sea level at zero and subtract the difference from each other point and terrain line.  It was pretty easy.  For example, my low point was 500 feet, and my high point was 554.  The low point became zero, and the high point became 54.