Need help creating surface from polylines and building outlines

[Anonymous]

I have contours and building outlines. The contours generally end at the building. I need to create a surface of the site. I have done this using JUST the contours and spot elevations with no problem. This is trickier for me as I now have to diplay the surface utilizing the building outlines as well. Do I need to"add" contours around the building outline, or do I simply make the building outline some sort of "boundary" that will still result in the surface accuratley showing the site? Same question for how to handle the walls.

To elaborate, contours range from 22' down to 10' elevations. Some contours will begin against a building wall and end at another building wall.

Please see attachment example.

Thanks!

[Pointdump]

Mike,

You can use a "Hide" Boundary.

Dave

[Neilw_05]

If you only have a few building then as Dave suggests, hide boundaries should do the trick. If there are a lot of buildings then it becomes a tedious process since you have to select and add each hide boundary (bldg) one at a time.

[tcorey]

Dave is right, you will accomplish this with Hide boundaries.

To elaborate, for those less-familiar with Surface Boundaries, when you add a boundary to a Surface, on the dialog is a dropdown list for Type. Drop this down and pick Hide. This will create a boundary that terminates all surface activity inside itself, perfect for buildings. If you want the contours to reach exactly to the boundary object, be sure Non-desctructive breakline is checked.

If there is an island within a Hide boundary, where you do want surface data displayed, use a Show boundary.

[Anonymous]

Thanks so much everyone!! I will give this a shot...I have 3 buildings and a few walls (I assume I would use the walls the same way)

[Anonymous]

OK..Follow up question. In between two of the buildings I am provided with contours going from the buildings to a swimming pool in between. The contours end at the pool, but I have the spot elevations of the pool. I assume I use the outline of the pool as a "hide boundary" for my surface, and then create a second surface of JUST the pool, using the outline of the pool with the assigned elevation, and the spot elevations of the pool itself.

Is there a way to then COMBINE both surfaces?

Thanks!

[Civil3DReminders_com]

Yes, if the question is to combine two surface you will find that under the Edit Surface drop down on the ribbon when you seelct the surface (or right click on the Edit portion of the definition in Prospector). 

If the surface is a part of the whole surface and you want to see them, then add your hide boundaries like you are doing and then do a Show boundary for the pool data.

[Anonymous]

Thanks! And to be clear, the contours are not required to go "through" the building in order to generate a surface that ENDS at the building when using the HIDE BOUNDARIES feature?

[Civil3DReminders_com]

Contours are a symptom of a surface and not usually the source of surface data. If you wanted accurate it would be to draw the existing building pad at elevation and then add it the resulting breakline to the surface. This would then have the contour go around the building rather than using brut force to erase it. Usually surveyors don't shoot both elevations (pad and adjacent grade), so we use the hack of adding a hide boundary instead of fixing the surface to reflect what is actually out in the real world.

[Anonymous]

The building outlines include different spot elevations at each corner. Is it possible to redraw the outline of the building and apply a different z-elevation at each corner (assuming thats what you mean)?

Or are you saying to just apply a single elevation to the building outline (the building pad?) That elevation information is not shown on the drawing. 

I just have this funny feeling that because the contours just end at the building, the resulting surface will contain some very erroneous peaks and valleys due to interpretation? 

[Civil3DReminders_com]

If later on I want accurate quantities by comparing the existing surface to the proposed surface, then the hide boundaries will cuase me not to calculate between in the areas of the buildings.

To get around this I'd take the shots the surveyor took around the building, offset it a small amount (0.1') to the interior of the building. I'd then adjust the elevation of the shots to an assumed elevation of the building pad at the bottom of the concrete pad. So I might say the concrete slab is going to be a total 6" below the surface and then assume that is the elevation for the entire building. This way I get rid of the obvious contour going through the building and still be able to have no contours going through the building. 

This is all surveyor and engineering judgement on how to approach it and what the deliverables are going to be. Me personally I usually don't care if the contours are going to through the building since it's probably close enough. Other people freak out about it since they think something has to be totaly wrong and then they question the rest of the survey. Which is wrong since the hide method ends up with the result they are looking for, but gives bad quantity values later on. 

I'm from hilly Southern California, so contours are crazy numerous most of the time. Other places are crazy flat like Texas where the contours going through buildings is less frequent.

[Anonymous]

OK...the purpose of this excercise is to compare the new surface to the existing for cut/fill calcs.