Answer Day - Civil 3D Surfaces

[fcernst]

How old is the programming code for Civil 3D surface creation and analysis? Is it still the same code from back in the Softdesk/LDD era?

Reason I ask is that it is not performing well (or at all) on new computers with data such as that derived from the USGS or LIDAR for hydrologic and other studies. It is also not using the available processor and memory resources on the new computers.

Please see this thread:

https://forums.autodesk.com/t5/autocad-civil-3d-forum/answer-day-civil-3d-performance-vs-games/td-p/...

[Charlie.Ogden]

For a large terrain such as that you could use the Create Watersheds command in InfraWorks.  There you can also use Rational method or USGS Regression equations to compute flows.

Or you can use the point cloud tools in InfraWorks to either create a simplified terrain to bring to C3D... or to bring a simplified point cloud over to C3D.  Thus maintaining it's integrity while creating a lighter surface.

[fcernst]

We want to stay in Civil 3D though..and not have to resort to once again another back and forth workflow.

What is different about the Infraworks surface code and algorithms such that they could handle this, and not Civil 3D?

Is the Civil 3D code old? Sound like it needs to be updated.

[dgorsman]

I think part of the problem is with the data structure.  The DWG database is restricted to single-record change operations, the program cannot change multiple records at the same time (i.e. what gets done with multi-threading).  Attempting to do so would result in an unpredictable outcome (race conditions, endless loops, etc.), as it has to handle all sorts of events both in-program as well as those added by third-parties and users with LISP, managed dotNET, and ARX.  As long as its on that DWG base the code, old or not, isn't going to change much.

Infraworks is built from the ground up, including it's data structures, so it can explicitly handle surfaces.  There's a lot more restrictions on what you can do i.e. I don't think you can use it to do electrical schematics, design a timber deck extension, *and* play a wigged out port of PacMan.

[fcernst]

or to bring a simplified point cloud over to C3D.  Thus maintaining it's integrity while creating a lighter surface...

That 611 acre surface contains 4.2E6 Ground points out of the 16.2E6 points in its LAS file.

Are you suggesting to reduce the 4.2E6 Ground points for use in Civil 3D?

[Cadguru42]

Is Autodesk looking to revamp the way C3D handles surfaces? As has been noted, the TINN model has many limitations and with computing power exponentially larger than it was a decade ago, why can't Civil 3D use the core AutoCAD surface object type or even a quad mesh? 3ds max can have a million plus polygon model and the interface zooms, pans, and rotates without issue, but a C3D model bogs down a more powerful machine. 

[fcernst]

Charlie,

I am just trying Infraworks for the first time because I was curious about the Watershed Analysis capabilities you mentioned. 

This routine in Infraworks is not the same as in Civil 3D where all the 5 types of Watersheds are created across the entire surface. 

This message is telling me this is behaving like the Civil 3D Create Catchment from Surface command..

[fcernst]

Giving Infraworks Watershed Analysis another try on a different EG surface of about 70 acres.

This is a deep culvert crossing under a County road. Three tries in the depression and Infraworks keeps failing to find a Watershed. 

Nice light shadows off the discharge point markers though..

[fcernst]

Still no luck..

[fcernst]

This time I sunk a sag curve road through this EG depression area. Even selecting the entire road, or a portion of the road as the discharge location, the Watershed command fails.

This location is easily analyzed in Civil 3D (3rd below).

xx

x

[fcernst]

[fcernst]

Pictures are not uploading...

[Cadguru42]

So basically InfraWorks can't even do what little design has been built into it?

[fcernst]

Seems so ...

I'm even more disappointed now that our Design Suite fees have been going to this, and not the betterment of Civil 3D,,. Especially the needs for the improvement of Civil 3D stormwater functionality.

We need drainage analysis functionality for Corridors for inlet spacing and sizing (street capacity). 

[Matt.Anderson]

Fred -

InfraWorks watersheds service use a different method of analysis - one much more focused on a larger issue and not limited by the Catchments/Watershed code found in CIvil 3D that hangs on depressions.  

The best way to look at it to consider InfraWortks is more TauDEM (Raster) analysis than Civil 3D TIN face fold analysis.   This means it more sensitive to the settings that are not shown in your images.  The default setting would likely fail your tiny surface model.  

The inlet spacing analysis does leverage the same function methods.  It estimates the catchments from the road geometry.  

Your question on code age is irrelevant. 

[fcernst]

one much more focused on a larger issue and not limited by the Catchments/Watershed code found in CIvil 3D that hangs on depressions.  

That pretty much makes no sense. You're saying Infraworks is not designed to handle this 63 acre surface scenario? It is suppose to do roadway inlet analysis and design?

Civil 3D has no problems with the Watersheds here, and does it quickly.

Your question on code age is irrelevant. 

Do you want to elaborate? I'm saying Civil 3D is choking on my 611 acre surface created from 4.2E6 Ground points, and it's not using all the computer resources. 

[Cadguru42]

---

@Matt.Anderson wrote:

Fred -

InfraWorks watersheds service use a different method of analysis - one much more focused on a larger issue and not limited by the Catchments/Watershed code found in CIvil 3D that hangs on depressions.  

The best way to look at it to consider InfraWortks is more TauDEM (Raster) analysis than Civil 3D TIN face fold analysis.   This means it more sensitive to the settings that are not shown in your images.  The default setting would likely fail your tiny surface model.  

The inlet spacing analysis does leverage the same function methods.  It estimates the catchments from the road geometry.  

Your question on code age is irrelevant. 

---

Code age is a very relevant question. If C3D is still using the original surface modeling TINN code from back in the SoftDesk days it does matter now that multiple cores and coding languages have changed. Optimizing code for use on modern hardware is something that should be done and that's why code age matters.

As to @fcernst's issue, it seems Infraworks failed to do what is advertised in regards to the watershed analysis. It couldn't create a watershed for a sag road, which is what it's advertised as being able to do. 

[Matt.Anderson]

Fred -

Correct - InfraWorks watersheds functions were design to handle determining the watershed for those surfaces that C3D can not build.

I can not tell what values you used for grid spacing or stream threshold when you attempted your analysis.  If you did not alter your values, you will NOT get a result as its looking for a much larger watershed.  Try a smaller grid and smaller accumulation value.  

The weakness of the watershed analysis on large DEM models with Civil 3D is what the InfraWorks tools was designed to solve. It hydro-corrects the surface based on the grid spacing selected.  (Lay terms:  It's a Raster-based computation typically found in GIS applications)

Review TauDEM documentation if you want a similar explanation of the computations.  http://hydrology.usu.edu/taudem/taudem5/index.html

Code age is irrelevant.  I.E. you're asking the wrong question.

You answer the right question by answering why one can and the other can't. 

[fcernst]

Correct - InfraWorks watersheds functions were design to handle determining the watershed for those surfaces that C3D can not build.

Really..? I thought it was suppose to be inter operative with Civil 3D..?

This is a 63 acre surface out in the County. It has only 2,865 ground points in it taken by a survey crew on the ground with traditional methods.

Infraworks has got to work with this type of topo product, and subsequent Civil 3D surface.

I have been trying with the minimum threshold settings..and other values on the scales too.

[fcernst]

In Autodesk's movie, John Sayre's watershed is only 66 acres. I'm not following you Matt..