Topography - Site development functionality = Poor (need cut only function)

Anonymous

Topography - Site development functionality = Poor (need cut only function)

Anonymous
Not applicable

I would really love to see some better site development functionality (topography modelling)

 

Trying to do a graded region where you can implement a building pad to only cut away the topo above the specified height of the building pad, but anything below that building pad height just remains the existing topography height.

Ie. Cut only graded region option, not cut and fill (which the building pad does)
The point heights are really painstaking and frustrating to work with. I often experience the "place point" - "relative to surface" function to be inaccurate. Where I would place relative points around the perimeter of the building to retain the existing heights of the topo, and then follow that with the desired cut height inside the perimeter of those relative points. Problem is that those relative points would often change the existing height of the area where I place the point height slightly.


There are a lot of buildings we design that are built on piled foundations (floating timber buildings) where the joists need to be min. 450m above ground level, (NZ code) thus requiring a gradient cut, but not a fill.

 

Does anyone have suggestions to achieve accurate topo model for the above?

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RDAOU
Mentor
Mentor

Hi @Anonymous

 

Toposurface "place point" - "relative to surface" is accurate, so is "absolute" it is just hard to control those points are being placed (especially when the surface is variable ups and downs (organic shaped). It is not the ideal way to create a site topo (by placing points) and it is more or less an option to create a site from a pdf scan maybe where you go clicking on curves and splines ie: lines to guide where the points are dropped ... => the inaccuracy you are experiencing is a human error and not a software bug/glitch

 

On the second issue; To build up a building pad; cuts and fills are required (So the tool is doing what it is meant to do)...Maybe I am missing out on something in the situation you described above; if your buildings are floating 450mm above ground  (no fill underneath) why are you using a building pads? Piles do not need a building pad either...

 

Maybe a with a bit more clarity and some section one might be able to help better

 

 

YOUTUBE | BIM | COMPUTATIONAL DESIGN | PARAMETRIC DESIGN | GENERATIVE DESIGN | VISUAL PROGRAMMING
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Anonymous
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Thanks for your reply RDAOU.

 

However I feel that the first point is not human error, as when I do graded region and place "relative to surface" points anywhere on the proposed site and finish the topo - there is a difference in triangulation from the existing topo to the proposed, even though I did not make any changes to height, I can notice in section how some areas are different in height where I placed those points.

 

Second point:

What I'm trying to achieve is to cut the topo where the building is going to sit. ie. some parts of the topo underneath the floating building are less than 450mm below the joists, and other areas are more. I only want to cut the topo where the area is less than 450 clearance so as to achieve min. 450mm.

No filling is needed in the areas that have more than 450mm clearance.

 

Please see attached pdf sketch for clarification

 

essentially I'm looking for a fast method of doing this cut instead of using points (painstaking+time consuming)

Do you know of a better way?

 

It would be great if Revit could incorporate a function that similar to drawing a pad (just a simple sketch of area you want to cut) and then specify the height

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Anonymous
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I know the problem you are describing, and you are right, it can be frustrating. It would be nice if the PAD tool had properties that you could tick where you can tell it to cut&fill, only fill or only cut. However, until that function arrives, I often use the split surface & merge tools. 

I also use this technique to form my topo for site elements. A post from way back in 2010 explains it: http://bimtionary.blogspot.com.au/2010/02/curb-and-gutter-along-topo.html

 

Downside though, you won't get your cut/fill calcs. 

 

Until Autodesk give some love to the new Site Designer tool extension, it really is 'work-around' city! 

ChrisNeedhamNZ
Advocate
Advocate
Accepted solution

One way that I do this which is reasonably easy:

  1. In the "Massing and Site settings" dialog, add a contour line at the required cut level.
  2. Then in plan view start the pad command, select the elevation required.
  3. Trace over the added contour line, and select any building edges etc.
  4. Finish the pad command, and you should get pretty close to what you need.

 

Chris Needham
Whangarei
New Zealand