My first parking lot EVER so, 2 questions

[Anonymous]

Bear with me today a little bit....I'm laying out a parking lot with S/W, curb & gutter, and although I've done a great deal of grading, since I work in water utilities this would be my first parking lot (it's for a pump station) so I have a couple of things that I'm confuzzled about....and I so hate to be confuzzled.

1) how do you do feature lines for both top & bottom surfaces, without them sitting on top of each other, which seems to screw them up?  For example, if a curb goes straight up, you would have a feature line for flowline and one for top of curb.  Right now I offset them just slightly from each other….is that the way to do it?  The only other way I could see to do it would be to put them in different sites….but I'm not sure how that would work…..

2) when I am done laying out all of my feature lines, what is the best way to go about making the new surface?  Would you copy the existing surface and add all of the feature lines as break lines to it to create a finished surface?  Or would you try to do an infill?  Please let me know the best plan of attack.....

Thanks for any help!!  It's appreciated!

[doni49 · Accepted solution]

1) C3D doesn't like completely vertical surfaces.  So offset the top of curb line by some small amount (I usually use 0.001").  That'll allow it to triangulate the surface.

2) I have feature lines representing the outer boundary and all breaklines within the lot.  I use those featurelines as breaklines in the surface and add points as needed for critical spot elevations.  Then I use a grading object on the outer boundary that seeks the EG surface.  The featureline that generates is the final outer boundary of my proposed surface.

[Neilw_05]

One of the rules of a TIN is no point on the surface can have more than one elevation, so you cannot have vertical faces or overhangs in a TIN surface. Typically we do as you mentioned, put a slight offset as an approximation for vertical faces.

As to how to manage the surfaces, the recommended approach is to create separate surfaces for your design and merge them into a composite surface which has the original ground pasted in for the base.

[AllenJessup]

1) Curbs rarely go straight up. They usually have a Batter. Check whatever detail you'll be using for the curbs to determine how much batter you have.

I usually model the bottom of curb and the back of curb at top. That way if you show proposed contours they won't form just a solid line at the face of curb. This will not affect the drainage flow.

2) Create a proposed surface from your Featurelines, Create a copy of your existing surface and paste the proposed surface in to it. Or you could also copy the proposed surface so you'd still have an existing, a proposed and a composite.

Allen

[Anonymous]

Wow!  Such quick help, you guys are awesome!!  Thanks very much, I'll try your suggestions.  

Again, thanks for taking the time to help me out. It's kind of fun laying out this parking lot.....