mlthrift

Elevation datums

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Good morning, 

 

I am currently working on a plan and am trying to add elevation datums to floors. 

 

I have a few questions - 

 

My first floor is showing at 0'-0", so is my grade level, even though my terrain is about 2' lower than the first floor. How do I get the auto story pole to see the terrain?

 

Second, is there a quicker way to make the 0'-0" for the first floor to reset to 100'-0"? 

 

Thanks in advance!

Marsha

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Move the whole model up 100'.

 

Edit:  No, that won't work.  Sorry.  You can do this using structure, but it's best to begin early.

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Thank you Gene,

 

I'll have to just let it go as is and remember to start at 100' with the next one. Dp you know is there a default I can set so that it always builds at 100' instead of 0? 

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I use first floor set to 0 as the program was intended.  Everything else, including terrain is set relative to the building.

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In order to change the dimension for grade in the story pole, open up your default settings, go to dimensions, then auto story pole dimensions. Once you have the dlbx open, go to the locate elevations tab. There is a spot called grade level marker where you enter the grade height. 

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Thank you Chris_Kelly, I was able to get the grade set and though it's still showing negative numbers below 0'-0", it split the grade. Thanks again.

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2 hours ago, javatom said:

I use first floor set to 0 as the program was intended.  Everything else, including terrain is set relative to the building.

 

javatom,

I'm trying to use 100'-0" as the first floor level as that is what the contractors are used to seeing. I'm not sure why a -# below grade is difficult to understand, they can measure down instead of up with no math involved. It seems a negative number would prevent errors.

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19 minutes ago, mlthrift said:

 

javatom,

I'm trying to use 100'-0" as the first floor level as that is what the contractors are used to seeing. I'm not sure why a -# below grade is difficult to understand, they can measure down instead of up with no math involved. It seems a negative number would prevent errors.

 

I really think you need to readjust your thinking and not try to make the floor 100'-0" from the default 0'-0" Z coordinate Chief starts at, but rather set your terrain information accordingly.  There are training videos showing this in the library.

 

I've also never heard of contractors using a set 100'-0" first floor levels - is that a regional thing?.  I know that above sea level or OHWM some start at 100'-0" instead of 0'-0", but you'd always then set the floor level in relation to the actual above sea level elevation plus the 100'-0".

 

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5 minutes ago, johnny said:

 

I really think you need to readjust your thinking and not try to make the floor 100'-0" from the default 0'-0" Z coordinate Chief starts at, but rather set your terrain information accordingly.  There are training videos showing this in the library.

 

I've also never heard of contractors using a set 100'-0" first floor levels - is that a regional thing?.  I know that above sea level or OHWM some start at 100'-0" instead of 0'-0", but you'd always then set the floor level in relation to the actual above sea level elevation plus the 100'-0".

 

I'll have to ask my boss if keeping the 0'-0" is acceptable as previous plans used 100'-0". It might be a regional thing. Here they teach to make the first floor at 100'-0" as the architectural drafting standard. The logic the instructor gave for it, was that it makes the elevation of below grade floors a positive elevation and not a negative. Honestly, the negative seems easier. 

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Your instructor is wrong.  I have never seen a first floor plan show at an elevation of 100'.  I doubt if it is a "standard" in any region.  Elevations on plans are set to show a construction crew how to build it.  Maybe you could post a pdf of a plan that used 100'.  Perhaps we are just not understanding what you are doing.

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It seems that surveyors commonly use a 100' benchmark and not necessarily sub floor level but whatever they feel is convenient.  I have had plans rejected by the building department because they were not done that way but feel that the negative numbers represent a fall in elevation much better and give a much clearer presentation when we can show them in red.  Just bureaucracy.

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3 minutes ago, javatom said:

Your instructor is wrong.  I have never seen a first floor plan show at an elevation of 100'.  I doubt if it is a "standard" in any region.  Elevations on plans are set to show a construction crew how to build it.  Maybe you could post a pdf of a plan that used 100'.  Perhaps we are just not understanding what you are doing.

 

I can assure you the instructor is not wrong as I have seen it on numerous plans, all drawn by local licensed architects. 

 

I can not attach a pdf, but here is a picture of one with the elevation datums shown. The first floor is at 100'-0" with the other floors and the footing with elevations referenced from this number.

UNADJUSTEDNONRAW_thumb_1ce.jpg

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Looks like it is regional, but your instructor (and the architects) aren't doing it 100% correctly - and for homes in your area perhaps its just fine. 

 

If a contractor comes out to a site and wants to set the floor elevation, how does starting the datum at that sub-floor actually help him?  Typically you'd use the actual site elevations, local survey monument, OHWM (if close to water), or some other marker that is already defined as the basis for the first floor datum.

 

Example:  A local monument in the street is 350.20' above sea level, and you want your FFL 10.50' above that elevation point, so the FFL is 10.70' and you note on the site plan, or site section where the 0'-0" point is coming from.

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Yes, ideally we would use the actual elevation of the site. These plans are for homes and in the bidding stage, so there hasn't been an official survey done. I'm actually not sure if or when a survey is even required here for new homes. The 100'-0" is simply a theoretical number. I'm thinking I'm going to add the datums in the detail and not use the story pole.

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Now that is a good idea.  You will satisfy the odd local requirement without screwing up your plan file.  That's what I call a win / win.

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Quote

I'll have to just let it go as is and remember to start at 100' with the next one. Do you know is there a default I can set so that it always builds at 100' instead of 0? 

You can change the terrain height (and the houses relative floor height) to 100' without redrawing or starting again.

Create a terrain and use some terrain elevation data that relates to your 100' reference - say across the middle of the site at 100', across the top of the site at 120', and across the bottom of the site at 80'.

This will build the terrain 100' higher than the house.

Open the terrain dbx and set the Subfloor Height Above Terrain to 100' (or as you want - 100' will set a flat terrain at the house floor level - Chiefs zero floor level).

If you generate Auto Storey Pole Dimensions, the levels will relate to the floor level being at zero.

This is probably not what you want - you probably want them to relate to your 100' which is your actual floor level.

Go to your Auto Storey Pole Dimension defaults...Locate Elevations...Grade Level Marker...change this to 100' and change the Elevation Reference to 1st Floor Subfloor.

Now all your elevation heights will relate to your subfloor at 100'.

 

Using 100' as an assumed datum used to be the norm down here.

100' was used mainly to keep all levels around the site a positive number.

We now mainly use an Australian Height Datum that is related to sea level.

Most jurisdictions now require this as it allows for easy relationships to adjoining sites and other services.

 

PS.

You can also set Chief up so that the Absolute floor and ceiling levels are reported as relative to your 100' elevation which means that the Room Specification dbx the Absolute Elevations will use platform levels relative to 100'.

But, from memory, I think you then need to set room floor levels on a room by room basis because the default floor level for level 1 is zero and cannot be changed.

You would not need to redraw to use this method - depending on how complicated the design is, you should be able to change your plan through the dbx's.

One advantage of using this method is that if you open a dbx for an object like a roof, the heights are reported as relative to your 100' height. ie, the roof ridge might report as something like 115' instead of 15' (relative to Chiefs zero floor level). This might be particularly important when you are using real world levels for your terrain.

 

In short, there are many ways (probably at least 3 or 4) that you can use to relate the building platform levels to the terrain.

 

If you are having trouble, post a plan and describe exactly how you want your terrain and building platforns to relate.

Or, let me know and I will do a quick Skype session with you to explain as it can get a bit involved.

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6 hours ago, glennw said:

Go to your Auto Storey Pole Dimension defaults...Locate Elevations...Grade Level Marker...change this...

 

I was waiting for somebody to give this answer.  I am not surprised in the slightest that it was from you good sir : )  I was away from my computer all day and couldn't answer because I couldn't rightly remember off the top of my head which tab that setting was under or what exactly it was called.  Here's one extra little tidbit though for whatever it's worth...

 

You don't actually have to go to your Auto Story Pole Defaults.  You can go to ANY of your dimension defaults and change the setting there.  Easiest way is to simply double click on any one of your manual dimensioning tools.  The reason you can change this number in any of your defaults is because Chief only allows you to set one Grade Level Marker number and Elevation Reference.  

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13 hours ago, glennw said:

You can change the terrain height (and the houses relative floor height) to 100' without redrawing or starting again.

Create a terrain and use some terrain elevation data that relates to your 100' reference - say across the middle of the site at 100', across the top of the site at 120', and across the bottom of the site at 80'.

This will build the terrain 100' higher than the house.

Open the terrain dbx and set the Subfloor Height Above Terrain to 100' (or as you want - 100' will set a flat terrain at the house floor level - Chiefs zero floor level).

If you generate Auto Storey Pole Dimensions, the levels will relate to the floor level being at zero.

This is probably not what you want - you probably want them to relate to your 100' which is your actual floor level.

Go to your Auto Storey Pole Dimension defaults...Locate Elevations...Grade Level Marker...change this to 100' and change the Elevation Reference to 1st Floor Subfloor.

Now all your elevation heights will relate to your subfloor at 100'.

 

Using 100' as an assumed datum used to be the norm down here.

100' was used mainly to keep all levels around the site a positive number.

We now mainly use an Australian Height Datum that is related to sea level.

Most jurisdictions now require this as it allows for easy relationships to adjoining sites and other services.

 

PS.

You can also set Chief up so that the Absolute floor and ceiling levels are reported as relative to your 100' elevation which means that the Room Specification dbx the Absolute Elevations will use platform levels relative to 100'.

But, from memory, I think you then need to set room floor levels on a room by room basis because the default floor level for level 1 is zero and cannot be changed.

You would not need to redraw to use this method - depending on how complicated the design is, you should be able to change your plan through the dbx's.

One advantage of using this method is that if you open a dbx for an object like a roof, the heights are reported as relative to your 100' height. ie, the roof ridge might report as something like 115' instead of 15' (relative to Chiefs zero floor level). This might be particularly important when you are using real world levels for your terrain.

 

In short, there are many ways (probably at least 3 or 4) that you can use to relate the building platform levels to the terrain.

 

If you are having trouble, post a plan and describe exactly how you want your terrain and building platforns to relate.

Or, let me know and I will do a quick Skype session with you to explain as it can get a bit involved.

Thank you! This is what I was looking for. I'm going to go as is for now, as I only have the section left to finish these plans. However, I will be adding these steps to my template to make the next home easier. You're input is appreciated!

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On 5/24/2017 at 4:32 PM, glennw said:

Open the terrain dbx and set the Subfloor Height Above Terrain to 100' (or as you want - 100' will set a flat terrain at the house floor level - Chiefs zero floor level).

If you generate Auto Storey Pole Dimensions, the levels will relate to the floor level being at zero.

This is probably not what you want - you probably want them to relate to your 100' which is your actual floor level.

Go to your Auto Storey Pole Dimension defaults...Locate Elevations...Grade Level Marker...change this to 100' and change the Elevation Reference to 1st Floor Subfloor.

Now all your elevation heights will relate to your subfloor at 100'.

Hi Glenn,

 

I can't get this to work.  I have the Subfloor Height Above Terrain set at 114' (actual height above sea level) but my Storey Pole Dims still show the Elevations relative to the first floor at 0.00'

 

I tried using Edit Area to move everything up 114' but that just made a mess of the Terrain, causing my structure to be on a 114' high pedestal.  This is a 2 storey house and editing all the room elevations may be the only solution but it will take a lot of time, starting with the upper floor and working down.  Do you have any other suggestions?

 

ps:  It would really be nice if Chief just had a setting in the Storey Pole Dims to add a value to the displayed Elevation Datum.  Maybe they could add a First Floor Elevation Datum Marker (a Special Marker) that would work similar to how a North Arrow deals with Bearings and Sun Angles.

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OK, I got this to work by setting the Subfloor Height Above Terrain to -114' (note the negative value) and specifying "Grade Level Marker" as the Elevation Reference.

 

Now my Elevation Datum is relative to Sea Level.

 

This is definitely not intuitive.  It has taken far too many hours to get this to work correctly.

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Hey Joe, I think you missed an important part of the process...You just need to go into one of your dimension defaults>Locate Elevations and change this number to -114'...

59c5377e57799_GradeLevel.thumb.png.150f97c66a336eaca74000ed95cacf59.png

This will keep you from having to move your model anywhere.

 

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7 hours ago, Alaskan_Son said:

Hey Joe, I think you missed an important part of the process...You just need to go into one of your dimension defaults>Locate Elevations and change this number to -114'...

59c5377e57799_GradeLevel.thumb.png.150f97c66a336eaca74000ed95cacf59.png

This will keep you from having to move your model anywhere.

 

 

As usual,  another nugget from Michael.

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I think you need to see post #20 in this thread.  Why does Michael get a point for repeating what I had already said?

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7 minutes ago, Joe_Carrick said:

I think you need to see post #20 in this thread.  Why does Michael get a point for repeating what I had already said?

 

 

Quote

OK, I got this to work by setting the Subfloor Height Above Terrain to -114'

 

 

Maybe I'm just misunderstanding what you said but that doesn't sound anything like the same thing to me.  I didn't suggest you change the subfloor height.  I suggested you change the grade level marker and for the record Glenn already pointed this step out up above.  It just seemed like you missed it.  

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No Michael, I didn't miss it

 

Glenn had said to change that to 100, not -100.  He also said to set it relative to the 1st Floor SubFloor vs the Grade Marker.  This was in the Storey Pole Dimension Defaults for Locate Elevations.

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