dtm and existing foundations

[digitalcarbon]

i had to use the site modifiers to get the existing foundation hole. now i have to use "proposed" to show it. hence it is no longer "existing"

[Miguel Barrera]

mechanix,

In order to modify the existing dtm, you need to add 3D polygons to the source layer. To make a hole, you add 2 concentric 3D polygons. The outside polygon would be the top of the hole and the inside polygon, which would be offset from the outside by a minimum amount such as 0.01, would be the bottom of the hole. The general rule is that the 3D polygons may not cross or be on top of each other.

[digitalcarbon]

ok, but will not my grade be set to the top 3d poly? which would be a flat plane.

the grade around the top of the existing foundation varies in height. what needs to be done is some type of subtraction tool for the DTM

[Guest]

When you create a pad, you can control the slope of the pad. You can also create several pads, all with various heights.

All the pads will be identified as modifiers when you switch to the proposed site model.

[digitalcarbon]

thanks for the thought but it is not really going to work well.

first and formost a "pad" is for proposed not existing foundation work.

we need to be able to subtract a solid from the DTM while not destroying it's DTM features. then we could cut out existing foundation holes and what not.

[propstuff]

ok, but will not my grade be set to the top 3d poly? which would be a flat plane.

the grade around the top of the existing foundation varies in height.

If you do what Miguel says but first select the top Poly and run Send to Surface; what happens then?

[digitalcarbon]

also need to cut out an underground "hole" for septic tank and bomb shelter.

the above is not really true, but i think we should have the ability to show things that are buried in the DTM

Edited July 16, 2007 by digitalmechanics

[Miguel Barrera]

I did not mean to use a polygon with just 4 vertices but rather a polygon with multiple vertices at varying elevations that would conform to the existing terrain. Granted that the more vertices that are included, it becomes more tedious to do a simple hole.

I agree that there should be a simpler way to do this. I know it can be done through programming because I have developed the tools to do something similar.

MIguel

[propstuff]

also need to cut out an underground "hole" for septic tank and bomb shelter.

You'll need to wait for the VW Fortification module to be released. ;-)

If you do what Miguel and I suggested you can get exactly what you want (minus the septic tank) in the Existing DTM. I just takes a little bit more work.

N.

[Guest]

I'm sorry, I didn't understand you needed the hole as part of the existing, not for a proposed project.