Site model on parking lot

[aheimann]

I am working on a project in which we are building a campus on a parking lot.

I want to create a site model which will sit on the model of the parking lot. The ceiling of the parking lot is complicated and has several inclines and different heights.

I thought about a couple options how to do it, but none of them seems to work properly.

1. Create a site model as existing with the heights of the parking lot ceiling and then add the contours of the final topography as proposed contour lines. The problem is, that I can not set my already imported 3D polys as the proposed contour lines. Additionally, I do not want to show any "skirt" which is lower that the ceiling of the parking lot.
2. Is there a way to cut of visible parts of the "skirt" of the site model? In a way erasing the lower parts, which I do not want to show.
3. Are there any other ways to reach my goal?

 

The thing is, I need to export the model as an IFC in order to import it into a Revit model of the Architects. There it needs to sit of the parking lot building and show in some kind of way the depth of the soil I have from the surface to the concrete of the parking lot.

 

Thanks a lot for any help.

 

 

[Jeff Prince]

So you are developing the roof of a parking structure?  I’m a little confused by your description.

[aheimann]

Yes, we are developing a park on the roof of a parking lot.

[Jeff Prince]

So is it a multistory parking structure with the roof above grade or do you have to tie into the existing natural grade at some point?

[aheimann]

The roof is basically above grade and on top of it we are planning our topography.

Additionally we need to develop the adjacent sidewalks. Therefore, there will be also development outside of the borders of the parking lot.

[Jeff Prince]

So this is basically a roof garden.  Why don’t you constrain the site model to the extents of the parking garage roof edge in plan view, disregard the actual natural grade, and turn off the skirt?  Wouldn’t this give you a topography that exists entirely within the area of interest and represent the surface needed?  I did something similar when learning the site model tool a while back to represent a surface above an underground bunker.  I constrained my surface to curbs surrounding the area of interest and was then free to use the grading and slab tools to develop the surface above the bunker.

[aheimann]

My problem is not to to constrain the topography on the sides. I want that the lower base lines of the site model matches the heights of the ceiling of the parking lot. 

So that at any given point I can see the depth of soil I have and therefore know where I can plant trees. 

I basically need a cut-and-fill model, which shows me the depth of fill on the roof.

 

[Jeff Prince]

2 hours ago, aheimann said:

My problem is not to to constrain the topography on the sides. I want that the lower base lines of the site model matches the heights of the ceiling of the parking lot. 

So that at any given point I can see the depth of soil I have and therefore know where I can plant trees. 

I basically need a cut-and-fill model, which shows me the depth of fill on the roof.

 

 

Perhaps the site model tool is not the right one for the job for the entire process in this case.  I’m no expert on VW, but here is the a variation on the process I used to use in AutoCAD or Rhino when faced with such problems.  Before those tools, we just studied the problem in sectional drawings.  At the end of the, everything will probably change when it gets built, so don’t kill yourself on the technical means of production 🙂

 

Solid Modeling for Soil Volume Estimations & Clash Detection on Green Roofs

1. Make your proposed topographical surface using your preferred topography tool capable of generating contours, ignoring the supporting structure’s levels.

2. Keep the topographical model intact for other uses, but export contours to be extruded in the next step.

3. Extrude the site model contours as solids, making sure to create an outline of the supporting structure’s roof boundary as well , and extrude it to at least as deep as the lowest point on your roof. Join/union into a single solid.

4. turn the boundary of the supporting structure into a solid by simply extruding it downward, at least as deep as your lowest point on the site model.

5. Subtract the roof from the topography.

 

The resulting solid will give you:

accurate volume

easy means of calculating loads at a given point on the model

visual means to check for clashes

 

Hope it helps,

Jeff

[aheimann]

That sounds like a good idea, thanks!

Could you describe me how I extrude contours as solids?

[Jeff Prince]

On 5/18/2019 at 7:24 PM, aheimann said:

That sounds like a good idea, thanks!

Could you describe me how I extrude contours as solids?

Hopefully this helps more than a simple verbal description...

I did a quick mockup to test the process in VW and to try out the terrain sculpting tool for the first time :)  Wow, that is a cool tool.  Keep in mind, I am just learning VW, so there may be faster, easier, or automated ways to do this.  This is just what I know how to do from many years of AutoCAD.

 

1 - Here's a roof deck I imagined based on your description. Note the different slopes, elevations, and parapet wall.

 

2 - Here is a VW "site model" I made using terrain sculpting that is confined to the interior of the parapet wall.  To create it, I drew a polyline on the inside of the parapet wall and converted it to a site model setting vertices at 6" so I could get smooth features.

 

3 - Same VW "site model", just represented as extruded contours

 

4 - No image, numbering error 🙂

 

5 - Same VW "site model", just represented as 2D contours, turn the elevation tags off before exporting to DWG.

 

6 - I exported the site model to DWG and reimported it into a new VW file to obtain polygon contours, perhaps there is a better way to do this.  I then went into the resulting VW symbol and copied and pasted them into my parking lot document.

 

7 - Polygons adjacent to the wall will need to be closed and now is a good time to check that all are closed.  You'll build a layer cake out of them essentially, just like making a cardboard model.

 

 

8 - By putting the polygons on layers by height, you will be able to easily extrude each height easily without error.

 

9 - My lowest top of roof face was set to 0, so my terrain is build up from 0

 

10 - check your works by comparing to the VW "site model" on the right.

 

11 - combine the individual solids of the terrain you have made, then subtract the roof deck from it.

 

12 - and here is what I believe you were looking for, from the underside.

 

12b - And how it looks from up top.  From the "model" menu, you can choose "volumetric properties" to obtain the data shown here.

 

Finally, you could make a solid representing a rootball of a tree, place the tree, and then rotate the model to see if there is a clash with the roof (if you see it poking out of the terrain model).

 

 

Alternatively, there is clash detection software for such things, but this usually does the trick just fine for me.

Edited May 21, 2019 by jeff prince