Grading vs Bounderies

[j_zapata_99]

Why would you use a boundery for a buiding or other types of foundation pads?

I am still new to Civil 3D, and was wondering why you wouldn't use a grading surface to create the foundation pad, unless there is a way to change that boundery into grading?

I have ran through some tutorials and in them they use bouneries for the foundation of buildings, but in some cases the surface is not level, or should i say the grading, elevation is not level. Wouldn't you need to know what you plan to cut and fill for that foundation?

Does a boundery do that?

[ToddRogers-WPM]

Use a Feature Line, right-click on it and Add to Surface as a Breakline.

[j_zapata_99]

Addding the boundery as a breakline will do what grading does?

Can you change a boundery to a feature line?

[ToddRogers-WPM]

You can create a Feature Line from Object.  Click on the Feature Line, right-click and select Elevation Editor.  There you can assign the elevation to the Feature line (FF elevation of slab). 

[Neilw_05]

I don't quite understand your question. When you refer to a boundary are you talking about the building outline, a property boundary or a surface model boundary? Also are you talking about computing volumes for the footings or basement or for slope grading around the perimeter of the building?

Typically when grading a building pad we would use the pad outline as a baseline for projection grading to determine it's footprint on the existing ground and calculate earthwork quantities. The building itself will also need to be graded to fit the pad and any adjacent site features such as sidewalks, parking lots, etc. How this is done depends on the site. In most cases the building pad outline is not used as a boundary in a surface model because you want the surface triangulation to form across the pad. However for the actual building you probably don't want triangulation inside the building footprint (unless it is a flat slab). To prevent triangulation you would define the outline as a hide boundary. Whether you apply it as a boundary or not really depends on the grading scenario.

[j_zapata_99]

In the turorials I was in the plan view, I created a boundary - Hide. I created it for a foundation or a house or building. I understand that was done to hide the TIN in the area of the boundary. I guess my question is how does this boundary transfer to a model surface ?

I am still a noob, and was thinking about this last night. Wasn't sure if there was a step or two that I haven't done yet to get boundary that I created to match the model surface. But I guess that is where the feature line comes in. 

If i get what you are saying right, you wouldn't use the boundary - Hide for surface modeling ?

[wfberry]

Unless something has changed recently, your hide boudary area will not calcuate any earthwork.  It is easier to mask it.

Bill

[Neilw_05]

If you are wanting to model the basement or footings for earthwork then you don't want to use a hide boundary. You will instead make the building outline a breakline and then add breaklines inside for the basement or footings. If the entire basement is in cut or fill you may be able to manually calc. basement volumes vs. trying to model them.

Again how you model the building depends on your site.

[tcorey]

Like Neil said, you need to know why you're putting the geometry around a building footprint.

In the tutorials, they have you make a hide boundary around existing buildings so they don't get contoured and used in other calcs.

If you are designing a building pad, which will be used as part of an FG surface, use Feature Lines and don't define them as surface hide boundaries.