The dsh Terrain Building Test

[Glenn Woodward]

D. Scott,

You missed a very important think in your latest video.
When you did a simple building on a flat terrain with no elevation data, you opened the Terrain dbx (Auto Calculate still checked) and the Pad Elevation box returned zero.
Well, this is wrong - as Gerry pointed out, the box has not updated.
Build the terrain and have another look.
Mine now says 200mm - which is correct according to "the formula", meaning that Chiefs zero floor level is 200mm above the terrain - THE TERRAIN BEING ZERO and Chiefs zero floor level being 200mm above a flat terrain at zero..

As far as I can see there is one thing that needs to be changed:
Get rid of the words "Pad Elevation" and call it "Chiefs Zero Floor Level" or similar.

This is the most important bit:
If you always think of "Pad Elevation" as what you want Chiefs zero floor level to be, you won't have any problems with relative, absolute, auto calculate, no auto calculate, etc, etc. - it will always work.

Try a few exercises using this method and you will see how easy it is.
This is the thought process I use and how I use Pad Elevation, and it always works easily.

If others want a way to change all the levels once specific site data is available, then this may be another improvement, but it's not important to me and is another issue.

[louis]

I do the same Glen and always have and I have taught it this way as well. Thanks for the post.

[Glenn Woodward]

Louis,

If Chief made that one little change to the nomenclature of Pad Elevation and everyone started thinking that way, we wouldn't be having this discussion - because there would be no confusion!

[dshall]

For over 4 years I have always set the PAD ELEVATION at zero. For the last 4 years I have always added a terrain region to then modify the PAD ELEVATION ht. It works great.... until I want the contours to read as my topo from surveyor, something I rarely get until after my house and pad has been built. Which now means I need to change the pad elevation and the terrain regions accordingly. I get that, I get that, I get that. No problem, easy peasy.

Glenn, you want to start building your new project but you do not have a topo, what do you set your pad elevation at? Probably zero. You still do not have a topo yet you want to drop your pad down below the f.f., how do you do it? Probably terrain regions. You now have your model built and your terrain built and now the surveyor gives you the actual topo map, how do you update your model.

The explanation for this line of thinking, and I have said this before, 97% of the time my model and building pad is built before I get the topo. Should I get the topo prior to beginning model, maybe, but it rarely happens.

You do not need to answer these questions, I am assuming you do it the same way I do.

EDIT: Glenn, I retract the statement that you probably do it the same way.... we get to the same place but take different routes. 99.7% of the time I initially build my building pad relative to house and then adjust later if I get a topo map.

[perryh]

The 6" added to the auto pad elev. is still wrong.

[gteacher]

Scott’s Terrain

Scott’s procedure sets the terrain reference point under the floor structure at 0”with a local region (His local marker point). The local region establishes the build pad and any needed landscaping in case drainage is a consideration. This assumes that the local site survey data will reference to that point, which it rarely does. Usually, it’s at some local corner, which means that all elevations planes would have to be multiplied by the relationship of actual marker height vs the building zero height (bias). An easy calculation, but a source of error.

Scott also requires that a surveyor will review his plan at some point and determine sea elevation at the building footprint. An hour or two of work, but something an Owner may not want to pay for. More likely a local marker is near in which the owner is aware. As in road center height, or top of sewage line height, etc. Using a local marker, not necessarily at the pad location, would require that the terrain zero point be translated to that location causing another bias(s) if building pad elevation is to be maintained at zero. Another source of error.

Finally, in not using auto-calc, you must determine “center point” terrain height yourself and do the math. All are 2minute cals, but another source.

Scott’s use of terrain regions for a bias source is advantageous, but regions are not always possible to use. Particularly, in W PA and W VA. If you cannot use regions, you multiply the number and type of data sources to keep track of.

In any event, even with this method, turning on auto-cal simplifies everything and eliminates “forgetfulness”. The only problem with auto-cal is Chief’s use of a fixed foundation bias of 6”. This simple limitation seems to be the reason for the confusion and why people will not use a valuable tool. Chief saved one input text box but effectively wasted hundreds of hours of programming on this – penny wise.

But this problem can be solved by just waiting until the end of the design, than open the DBX Pad Elevation, and add whatever to the reading. I agree that Scott’s method is viable, but with the various applied practical conversions and cross checks, not more so then anything else.

[lbuttery]

Glenn:

how would you do the Denver challenge in post #68 ???

I think your last reply covers it but I'm not sure ???

I thought Scott was going to do a video for this challenge ???

Lew

[gteacher]

IF yous Guy want to know what the confusion is here you might want to look at Scotts video in his Post # 71. I just did. Scott's video in which he was critical of Lew's plan, perfectly shows that Lew is using Chief correctly and was correct in the video even though Scott did not realize it. Scott was simply insisting that Lew do something which you normally would not do. Set terrain at bottom of f.f wood structure.

Chief made the correct adjustment when Scott changed elevation - my point and Lews

Scott, there is a difference between setting elevation for a monoslab and a wood floor w/foundation. Also, with a monoslab, Terain is set at the bottom of the slab, not the footer.

Lew: I don't think I have to make another video, I couldn't improve on Scotts.

Auto-calc works perfectly well. Another feature, seldom used because it's limited and confusing. OOPS --- said that before.

[lbuttery]

my point and Lews


Gerry:

for the record I was trying to comply with Scott's challenge with auto-calc off and with auto-calc on

I made a mistake with the auto-calc on plan which is the one Scott used in his video

so my "getting it right" was by accident


Lew

[Bradley Boltz]

And at the end of this long and interesting thread, I still don't know how to properly or accurately use contours and house elevations. Probably because of a minor dislexia but using a positive number, 12" to indicate that the "building pad" is 12" below the 0'-0"(relative first floor hgt which is now finish floor hgt or rough floor hgt?) always seems wrong to my brain. Then it goes downhill from there.

Will have to read that chapter in Terry Munsen's new book and get back to you. Sorry Doug, but as intuitive as many functions in Chief are, the lack of a real "sill plate" for foundations and the way the contours etc work are far from intuitive and this last monster thread from some relatively intelligent and tech savey Chief users is evidence enough.-Brad

[Doug Park]

So as I understand it.

1) "Pad Elevation" is confusing. Got it. Not sure what wording would be best. To be clear this is the offset between the vertical terrain coordinates and the house coordinates. Suggestions on a better name are welcome.

2) There is a bug somewhere with terrain not updating. If someone could report those steps directly to support I would appreciate it.

3) A feature request to specify the relative offset from the house zero for the auto calculation.

Anything else?

[gteacher]

Doug

You missed the MOST - MOST - MOST important talking point and request here!!!!

Add a option bias (input field) to raise/lower all terrain elevation data by "x " amount

Second point Pad elevation (pad bias - better) needs to be set on a individual floor structure bases, to account for different building floor structures on the same Topo at different locations.

Third - Allow the user to determine the pad center point as an option. This would eliminate all "guesses" as to what the terrain elevation actually is at "what" point. This is VERY important is deciding cut/fil.

Last - See my comment about adding a local marker and data being rel to that.

[lbuttery]

Scott:

excellent video !!!

I now agree with your method 1000%

and with your suggestion for doing the contours in relative terms to the house

thus, Chief needs to add the suggested setting so that we can display those contours as absolute sea level values if we need to match the survey

Lew

[gteacher]

Scotts method ONLY works if you are using regions to set your elevation data. A region is mandatory to establish the building pad and drainage. But----

If you use shot point data as most lots do here, Scott's method does not work because regions do not modify shot points(and user entered anything). Keep in mind that the shot point data comes before the house location, since with a initial lot or a development, you have no idea where to locate the house until you analyze the contours. And cut/fill is a prime consideration.

Also, if Scott had simply left on auto-calc, he would not of had to modify the out building floor level. Still 5 1/2 vs a dozen. Scott insist that contours be related to floor level- his personal preference. I do not, but if Chief adds the concept of a local marker, the issue is moot. Hope Doug reads ALL the posts -- Hmmm probably not.

[lbuttery]

Gerry:

thanks for the info

I've heard the recommendation to avoid "elevation points'
which is what I think you call 'shot points"

I've not had any survey using those but who knows some future project may ???

good to know

I also wonder about elevation lines
as the method my partner and I have been using (per recommendations) is to use regions to get a rough draft of the terrain and then use elevation lines to fine tune

it would probably be a reall PITA to have select all of the various regions and the various lines and set them to absolute sea level
and then flip back to relative values again

for now until chief offers a "switch" it would probably be best to use relative or absolute and not switch back and forth

Lew