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Patrick Fritsch

Positioning a Bldg on DTM without using site modifiers

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Maybe someone could guide me? I'm trying to figure out the best practice to position a Bldg on a DTM. I've set the X,Y tentative position easily in top plan view but my problem is to set it at the proper Z elevation. I'm trying to design the bldg in function of the natural site slopes which is pretty steep so I don't want to use any site pad modifiers just yet that will create a flat spot on the DTM at the bldg perimeter.

The other part of the difficulty is how to draw the stepped footing that follows the DTM grade while ensuring that I maintain the minimum frost protection of 3ft to underside of footing, there is a whole lot of lines to look throught the elev views of the DTM.

Any suggestion much appreciated.

Edited by Fritsch

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You could create temporarely section viewports to get what you want to know. There is also a command that gives you the dtm profile over a path, but I don't know the name.

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Create Contours perhaps in the 3d Modeling Toolset

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Patrick, I would start by thinking about how we used to do this, before computers. We would draw many sections and from those find the closest approximate 'point on grade' at each footing, foundation, etc. Then we would interpolate from one section to the next.

In VW's I would approach this problem in a very similar way. Placing the building at the correct Z height (or elevation) is fairly easy. If you know the approximate elevation, just set the Layer Z value to that number and draw a couple walls or extrudes, then cut a section or two to verify, or view in 3d to check... Then adjust the Layer Z values as needed to tweak it just so...

Also, I use Site Modifiers all the time and find them VERY useful for this type of work.

P

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I started doing exactly as you say Peter, first a rough bldg elevation position then a section viewport at every bldg face to check ground cover of my foundations...At least I don't have to extrapolate the grade section profile like I've done on a drafting table many times before!

I was kind of hoping the software could figure out the fndt stepping for me, I guess the BIM DTM/Fndt walls is not smart enough yet!

Edited by Fritsch

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I do seem to remember a feature which allowed the fitting of a retaining (or foundation?) wall to the DTM, but I can't seem to recall what or where it is at the moment. I will continue to look and post back if I find it!

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I've set the X,Y tentative position easily in top plan view but my problem is to set it at the proper Z elevation.

Modify>Move>Move 3D? Then enter Z offset.

Edited by Kizza

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You could create temporarely section viewports to get what you want to know. There is also a command that gives you the dtm profile over a path, but I don't know the name.

AEC>Terrain>Site Model Section?

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You could create temporarely section viewports to get what you want to know.

We would draw many sections and from those find the closest approximate 'point on grade' at each footing, foundation, etc. Then we would interpolate from one section to the next.

In VW's I would approach this problem in a very similar way.

In relation to this and with 3D modeling in general in mind, the need for live sections is painfully obvious.......just being able to select and edit slab/wall/window etc. OIP info through section VPs would be a huge asset.....

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Duplicate a 3d locus along the path of the perimeter & move a point to each corner

Select all loci

Send to surface.

Move 3d z= -3'

These will represent the min depth for an undisturbed terrain.

Cycle through each 3d locus on in the OIP and

drop adjacent loci below this plane to reduce the number of steps

Use 3d loci to create 3d polygons on a new layer for each of the step levels

Select foundation walls & Fit to Roof constraining the bottoms to the 3d polygon layer.

& underpin the walls

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Lo and Lo!

Send to surface also works with walls. Providing an instant trace of the surface along the lie of the wall.

Editing the wall in Elevation should then prove extremely useful in achieving this.

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what a cunning trick

ubbthreads.php?ubb=download&Number=7547&filename=Editing%20Peaks%20of%20Wall%20after%20Send%20to%20Surface.png

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Canadian's my cousin toungue!

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