Grading Small Lots - Best Practice Suggestions?

[mikeshick]

Most of my grading projects involve single family residence and usually nothing too complicated.  However, due to the nature of custom lots, I generally find myself grading with mostly feature lines, gradings, and generally a corridor for most of the driveway.  I'm curious if others have any suggestions for this type of project.  I've attaced mine for a sample.  Would love to hear your ideas.

Maybe this should be a seperate post, but I've also got a question about possibly superelevations.  Generally my driveways consist of have a single cross slope, but sometime I need to converge drainage in the middle or change cross slope the opposite directions.  What's the best way to accomplish this, and provide transition between these cross slope changes?  Is superelevation tool the key?

If you take a look, I may benifit using the layer state manager for alternating between my design setup.

Here is the link for the DWG.

Thanks.

[Joe-Bouza]

Hi Mike,

I'm not in front of Civil3d now, but I have bee having excellent results with grading object! I used to shy away due to stability and gaps that's I could not figure out how to resolve.

The stability is getting better, I use judicious sites and audit and purge frequently. For the gaps I could not resolve; I finally figured out that "infill" is not only for the bottom of a basin. A few grading can be tied together with FL's and unfilled. No more unresolved gaps.

Maybe you already know that, but it took me 3 years to get it to click.

Maybe that professional trainer would have given me that tip way back

[ralstogj]

Hi

I typical use grading and featurelines here are some links

http://c3dxtreme.blogspot.com/2011/05/urban-infill-subdivision-lot-grading-on.html

http://c3dxtreme.blogspot.com/2011/12/quickly-removing-breaklines-from.html

http://c3dxtreme.blogspot.com/2011/06/another-grading-paper.html

Regards

Justin Ralston

[Neilw_05]

I'll concur with the others about using gradings. Corridors are very capable but they are tedious to set up and manipulate and they don't handle transitions as well as gradings & featurelines. I'd also consider how the contractor is going to build the driveway. Is he/she really going to use superelevation parameters? I would think some slope labels and spot elevations at key locations are all that are needed.

What I would do is use the driveway centerline alignment and profile to create a featurline and then use that as a reference for applying elevations to the edges.

BTW, Nice job modeling that site Mike.

[mikeshick]

Thanks, Niel.  I appreciate everyones comments.  Sounds like we're all using it pretty much the same way.  I'll dig into John Mayo's AU class and Justins blogs. Yes...gradings have become much more stable the past couple of versions...thank you Autodesk! 

Also, I understand your point about how it will actually get graded.  In fact, I imagine that the majority of the time, these grading plans for customs lots are largely to get everyone pretty close, with final grading generally different based on the contractors hand's on preference.  Most of the contractors I work with will make field changes plus or minus several inches or even feet...so my approach has always been give them something that can work...if they change it, that's on them. 

Because I've spent most of my last several years in structural work, I've not kept up with C3D the way I prefer...so I hope there were some workflows that provided more dynamic/automatic flows.  Even though feature lines are wonderful advancement from LDD, and corridors, dynamic labels, etc, this type of site is still incredibly tedious to set up.  Then, once changes start up, ie. (contractor wants to change the grade at various parts of the driveway, architect wants to change the FF due to height limits, (both of these have happened on this project), because of no real dynamic element in the design, some tedious tasks ensues.  I would never want to use LDD again...I love C3D and the many advances it's made...but always looking for more automation 🙂 

As for the corridor or changing cross slopes, I have usually just made abrupt changes in my corridor, like I did on this project.  Sometimes, I'll space out my frequencies a little to aid with a perceived transition.  But what I'm really after is being able to set up the model and then fly by with my spot grades without having to put much thought into them.  I only recently starting using spot elevation that are "mostly" dynamic with the surface.  I

Let me throw one more bugging question I've had for quite some time.  I used to be really good with standards.  I have played an integral part of CAD standards at 3 different companies...and always made a strong effort to stay organized.  With the advent of C3D, use of object styles, I have lost some control in recent years.  I've found it incredibly difficult to manage layers like the days of LDD and Softdesk.  I suppose much of this struggle is attributed to my working now primarily as a one-man-shop, splitting my time between running a company, providing structural engineering, keeping up with AutoCAD Architecture, trying to learn Revit, etc. etc.  But just wondering, after all this ramble...do you all have a similar challenge in this area.  In bringing this out, one of the CAD elements I miss the most about more simple days, is I used to leave the discipline letter off the layer, and go straigt to the description of the layer.  This made a search for the layer quick, as I would click the toolbar layercontrol and type a couple of letters....and wala, I was there.  The tool still works, but it's very difficult to type C-Tin....quickly enough for that tool to be effective.  Maybe this should be a differnent topic as well...but any thoughts on layer control. 

I appreciate all your input. 

[Joe-Bouza]

Hi mike,

Not sure  I followed your question on standards fully, but perhaps adding some judicious layer filters in you template would be helpful.

[jamesmac1200]

Everyone's contributions are great. I've attended Autodesk University 2011 (3rd one) and attended a class called CI5241 - "Island in the Asphalt: Parking Lot Grading for Commercial Site Projects". This particular class was recorded and the video was great. The presenter introduced a workflow for grading a site keeping it very simple. If you have the access, I suggest watching it. Its about a hour and a half. Although the class indicates "commercial sites" you'll find it helpful. I've used the workflow with much success.

James E McClendon

CADD Tech

[Neilw_05]

Mike, most of my work is on sites just like your example so I completely understand your points. I'm amazed at how your comments are just the issues I've had and have.

In regards to the standards, for the very reasons you mentioned we decided not to implement the NCS. Since all of our work is civil the discipline code is just added baggage. We dropped the discipline code and created our own classifications. Layers begin with SITE, PROF, UTIL,TRAF,PNTS,GRAD, etc. This makes on the fly filtering efficient and we can easily isolate the info we typically need with a single filter.

As to Civil 3D's style management, I've not had time to develop a template to suit our standards so I've had to manage with the default styles. I've been contemplating making a template that has all styles set to layer zero. Then all the features would inherit the symbology of the layers. The part I haven't figuered out is how to deal with the components of the objects (i.e. layers for contours in a surface object). I don't have a solution at this time but I agree that this is a problem for us.

Lastly with regard to having a more dynamic model, I find the grading tools to be a major weakness for Civil 3D for several reasons. Gradings are unstable and prone to corruption and crashing. Also they are so slow to process that I hate using them. Too gradings cannot handle mitered corners so if you have mitered curbs with sidewalks you can't model them with gradings. Featurelines are pretty handy but they can be a pain to work with since they don't respond to standard Autocad editing tools (i.e. changing the radius of an arc to pass through a point). Since they don't have the ability to maintain relationships to each other there is no way to build a dynamic model without gradings or corridors.

Due to these issues I've favored Bentley's Power Civil product for site grading. Unlike C3D, it uses all native cad elements and it has the ability to maintain relationships between them. For example you can have 2 non-parallel elements of any complexity including splines and apply a slope and vertical offset relationship between them. If you edit the alignment or elevation of the parent element, the slope and elevation relationship is propogated to the child. Also if you drape an element onto a surface, the element updates when the surface changes. This makes it posibble to create planar drape surfaces which you can use to adjust your entire site by manipulating the drape surface. For example if you have a parking lot that slopes at 2% from crown to curb. just create a simple crowned drape surface and drape all the curb lines on it. Then if you change the slope or elevation of the drape surface, the entire lot updates. The software is very powerful in this regard but it has other problems that have made it less than an ideal solution. They have been developing new technology that will address some of those issues and if it works well in the next release it could possibly be an incredibly efficient way to model sites.

[mikeshick]

Ah...Neil...so refreshing to hear your comments.  Ditto right back!

I have vasilated and delayed setting up a more refined template file.  Some of my objects come in at 0 layer.....which I dislike the extra step of then placing those objects on their appropriate layers.  Then other objects I assign to a specific layer, but those generally need to get moved to a different layer with more description (ie.  C-Topo-Feat to C-Topo-Feat-FG).  Wouldn't mind using the suffix option in feature line creation, but tired of shaking my dialog boxes everytime I open them so I can see all of the input boxes - a problem that occurs from using dual monitors (see thread).

Better get off my griping saddle and get back to work.  Thanks....and look forward to seeing what others have to say!

[Neilw_05]

I run dual monitors and haven't had the problem in that thread. I can understand the annoyance it would cause.

As for having objects inserted on layer zero, you can control the default layer in the ambient settings and the command settings for each type of object (in case you weren't aware of that).

[jmayo-EE]

Two more thing you may want to keep in mind.

Sometimes a project will have 2d linework complete before grading is done so bulk zoning criteria and layouts can be checked first. If this is the case 2/3's of the work is done, x and y in the 3d design. Convert the 2d linework to feature lines and assign elevations. This is by far my fastest method to a FG model. There is no need for gradings, corridors or any other nonesense to slow you down. Just assign the Z values you want. 

Simple corridors with generic links can be used to quickly create feature lines for long driveways and larger retaining walls without using corridor surfaces or getting too detailed in the corridor programming for these smaller sites or retaining wall projects. I still mostly use feature lines on small sites but there are times when a corridor or a grading will get me the feature lines I need very fast. The gradings I find best on commercial and multifamily sites but I still shy away a bit and cannot comment on 2012's grading stability improvement yet. I have lost work with corrupt gradings on  07, 08, 09, 10 and 11.

[ralstogj]

Another good AU paper on grading and alot more that Paul Baker did a couple of years ago

http://au.autodesk.com/?nd=class&session_id=5510

[Joe-Bouza]

Hi Neil

what is the issue with mitered corners?

[Neilw_05]

Try it with a grading Joe.

[jmayo-EE]

Miters are for gradings but you can get similar results on a corridor by putting a very small radius curve on the daseline alignment. 😮

[ralstogj]

Joe

If I am understanding the question is it that you think the 1.64% should be 2% along the ridge.

I would of thought that what you have is correct as the ridge length is longer than the perpendicular

length therefore the same change in elevation over a longer length will give a small grade.

[Neilw_05]

This screen cap illustrates the problem with gadings and corridors. The green lines on the left are the required curb and sidewalk. The yellow on the right are the results when the curb and SW are modeled from edge of pavement (blue line) using gradings (or a corridor with small fillet). There is no way to have the curb and sidewalk dynamic to the pavement without the radius using gradings or a corridor.

[ralstogj]

Corridor with 90 degree bend

http://andrewscivil3dstuff.blogspot.co.nz/2011/06/create-corridor-with-90-degree-bend.html#more

use offset alignments and the unrdan side walk and set the inside and outside berm targets

[Neilw_05]

Justin,

Can you post a screen cap of a model with curb and sidewalks using that technique?

[ralstogj]

Neil

True the curve will offset in the alignment at the wrong length. I guess you could look into using constraints and having a polyline at the centreline and the alignment location it may work but still not dynamic.