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It appears that when you import a C3D drawing TBC does not properly interpret these as 3D polylines.  it appears to convert them to elevation zero.  however, if yu explode them in C3D and import them, they are true 3D polylines.  Has anyone else experienced this?

Ron: I have the same experience. We just make a habit of exploding the Feature LInes from C3D and firing them off to TBC.

Marshall

I don't believe TBC will import any C3D proprietary entities, e.g., feature lines, cogo points, corridors, gradings, surfaces, alignments, etc.  Most of these things can be transferred via XML to TBC.  

I would be careful importing C3D files with any special entities drawn.  TBC will import the file but can do weird things with the resulting C3D entities; sometimes it will create text literally millions of coordinates away, among other things.  I spend a great deal of time filtering all the C3D entities out of the DWG before I import to TBC.  You can use QSELECT in Civil 3d to ensure you have all the civil entities exploded or removed prior to importing to TBC.  Be careful of your order of exploding, too, as the civil entities are usually dynamically linked so any modifications to, let's say a surface, can change other things like gradings or corridors.  

Well, i use C3D for every DWG CAD file to dumb it down to basic objects.  however, when i gave my presentation and was going to include a little bit about this, i was told to remove this and TBC could handle this.  experience tells me, there is no way around using C3D to clean and extract the information.  there is no way i can get the design engineer to do this for me.

i am really just pointing out that a direct import is not clean and a lot is lost.

I agree with this Ron. We ended up buying Civil3D because sometimes we can't wait for and engineer to run the commands or they flat out wont. I've been told we're taking their jobs, and they won't do anything to help us out. I have noticed AGTEK will import most of the CAD information, but you lose layering. So that's inefficient if you need a lot of data from it. Having Civil3D is almost a must.

we have a significant procedure documented and we spend from 30 minutes to a couple hours.  first thing we check is the units US ft vs International, this can really mess up an XML

I’ve found that many, if not most engineer/architects I interact with use C3D. I was also told by a few users that C3D is a piece of software that requires 10K-15K of hours to become proficient. Therefore I find that the CAD drawings I receive are in varying degrees of usability and accuracy. It seems that the designers are not necessarily making fully construction grade drawings. Their scale is broader and somewhat more generalized. I have found their 3D work (like LandXML files) can require them to do addition work for it to be accurate. Particularly if the drafter is not a long time user of C3D. So I generally do not trust any 3D linework I receive and end up redoing the lines anyway. I did try making use of their work and found I spent hours only to learn it had enough flaws to not use in the end. I also found that some of the LandXML surface files would have their materials layering mixed and give bad values. Fortunately I can generally get them to send me “dumbed down” AutoCAD drawings with useable 2D linework. I also do not own/rent any Autodesk software. I bought Bricscad a few years back which helps me deal with CAD files. In a recent update I noticed that C3D files were being interpreted better. So CAD files that were once full of rectangular boxes were now mostly useable linework.

I think that until agencies and project owners fully comprehend the value of machine control for construction we will keep getting half baked plans. It is expensive to have engineers and architects build fully usable constructable models. It is cheaper to give it to the contractor who ends up having to finish and create workable plans. More work for me and I know the data I give to field works and is accurate.

If I had more use for C3D it might be valuable to have. At this point though the extra expense and time spent learning it don’t pencil out.

There is a setting in Civil 3D called Proxygraphics, it is a toggle and can be set to 1 or 0.  If you set it to 1 and save the drawing you can import the drawing into TBC and the AEC objects (Contours, Points, Corridor section lines, profiles, etc) will all import and be CAD lines in TBC.  Combine this DWG with the Project LandXML and in most cases you will have the data you need. 

The the Civil 3D Feature Line object will import as a 2D line and maintain its Curve Geometry. (but lose its 3D Elevations) This is because Autocad does not support a 3D curve.   

If you want the Feature line to keep its 3D property then there is another method and command called "Civil 3D Export" This will convert the Civil 3D AEC objects into CAD objects and the Feature Line will maintain its 3D elevations. Trade off is if the feature line has curves you will get a tessellated 3d lines string. (No curve geometry).  In most cases this is probably fine as these feature lines are breaklines or pads and may not contain curves.

From my experience the Save Proxygraphics option works everytime and then take advantage of the Elevate Line command in TBC to quickly convert feature line back to 3D.    The Export Civil 3D Command is prone to crashing Civil 3D, but does work most of the time.

I did a class at Dimensions on Understanding CAD Object where I went over and explained what happens with CAD when imported into TBC.   Here is a link to the Knowledge App in the Trimble Library where I've documented this information.

Mike, the issue is you have to have C3D to change those settings.

i have found it is well worth the price to own C3D to extract and or dumb down the elements.

it is virtually impossible to get the engineer to do this for you.  either they won't or don't have a clue what you are talking about.

Ron,   Asking the engineering to supply the DWG with the Proxygraphics variable set to 1 is a simple request and is not asking too much. The Export process is where the Engineers have a rub because it crashes and doesn't always work so they won't spend time to fix the issue with the drawing to get it exported.   The Landxml issue you bring up is an easy fix as well without having to go to Civil 3D as it can be edited in xml editor or notepad.

I understand where you are coming from with your perspective on needing Civil 3D,  as building models is your business. So having every tool to deal with any issues with the multitude of drawing issues you may come across would make sense.

Simply asking for the data with the Proxygraphics variable set to 1 and a Landxml I don't feel is impossible and the more  and more we educate the engineering industry on this the better it will be.  

you are assuming the engineers are our friends and will communicate with us.

Hi all

I'm working with 2018 C3D and 2019 Trimble Access - General Survey. 

I find it easy to take a 2D dwg drawing, save it as dxf before I Import them into Trimble Access to stakeout on site, but when I have lines and curves in 3D dwg drawing, save them to dxf and then import them to Trimble Access then everything disappears. Is there not a way to export 3D polylines, feature lines or alignments directly from C3D to Trimble Access and stake them out on site with General Survey? 

It is so easy to be able to pick lines in active map and stake them out but I want to be able to stake them out at correct elevation also.

I hope you can help me with this as we recently purchased 3 sets of Trimble Total Station and T7 Tablets and we need to be able to used them as we were hoping.

Thanks 

Helgi Valgeirsson 

Helgi

One of the challenges with DXF / DWG Files is that they really dont support 3D lines that incorporate curves (Arcs, Spirals, Vertical Curves, Vertical) at all - in a DXF / DWG AutoCAD itself has to create the 2D Arcs on a tilted plane (UCS) in order to give it elevation at all. The challenge that we have is that in TBC we have Lines that are “smarter” than lines that are supported in an AutoCAD DXF file, so we have to “Down Grade” the lines to something that a DXF File can work with.

In TBC we have the following Line Types and I will try to indicate what happens to those in a DXF / DWG File and maybe that helps you to work through what to do to get what you need in Access.

1. Alignment - this includes a Horizontal and Vertical Alignment. Those can contain Spirals, Vertical Curves (Parabolas) and Vertical Arcs none of which are supported in a DXF File / DWG File. So TBC has to “chord” those lines to be able to write them as 3D lines to AutoCAD. It uses the Project Settings - Computations - Surfaces - Beakline Approximation Parameters to do that. These specify an “Arc to Chord tolerance” that when exceeded forces the export to drop a chord point into the output lines. The output line at the chord points equals the original alignment. The lines between the chord points will be “off” from the original design by as much as the arc to chord tolerance that you defined in Project Settings - ie if you use a 2mm tolerance your lines can be off by as much as 2mm from the source line at all but the chord points (mid chord). We apply these in Horizontal and Vertical - so either type of curve is chorded on output

2. Linestring - a linestring can incorporate Arcs in the Horizontal and Vertical Curves and Vertical Arcs in the Vertical. The lines can have independent elevation points defined on the line (that are not at 2D nodes of the line) and these are exported as nodes in the output line. Because DXF doesnt support 3D Curves or independent elevation points or vertical curves or vertical arcs in a line, we have to again chord these lines if they are 3D and incorporate any of these elements.

3. Polylines - typically in TBC a Polyline is a 2D line with a single elevation like a contour. If it contains Arcs and Line segments only then this will go out as a Polyline and work OK in a DXF file. If you use the “Smooth” option in the polyline properties, then it will go out to the DXF as a Spline curve.

4. CAD LINE - this is typically a 3D line that has no curves in it, if that is the case then this goes out as a 3D Line into a DXF file and should work OK in AutoCAD or Access.

So AutoCAD DXF is an Old Format to use and really is less than ideal for Field Stakeout. Access also supports two other forms of linework data which you may find better

1. LandXML - you can send out one Alignment plus a lot of 3D lines in a LandXML - however all of the lines in the LandXML are chorded and need to be made into a surface in TBC in order to output them as linework - so you will lose your curves on road pavement edges and curbs etc - so maybe not much better

2. Moss / MX GENIO - again you can send out an alignment plus multiple 3D strings - again these are chorded lines so again maybe not perfect - if you want to use this format you may want to look at the Rockpile Solutions TML for Moss / MX Export as that gives a lot of control on how to take TBC data and map it correctly to an MX GENIO file output. MX files do support what they call 6D strings that include curves but Access does not support those as far as I know.

3. What some people do is output a Surface for Elevation control and a DXF file as 2D linework - that way you get the Horizontal Curvature for linework and a surface for elevation controls. Some people output 2D and 3D lines on different layers so they have data for each type of work.

On the Construction Side we use SiteWorks as our controller so I am not as familiar with Access - you may want to check out the Geospatial Forum and ask for input there as they may have some other suggestions. We have just started to use TBC VCL files in Siteworks so that we can leverage the smart data that they contain compared to DXF, LandXML etc which all have their place but don’t really support “Site Layout” as well as VCL files do.

When you output a DXF File you can elect to output as 2D or 3D - the two options will affect what gets output to the DXF file based on the source object types in TBC.

Here is a link to a video you can download that covers this in a bit more detail

Click Here

Hi Alan

I just want to inform everyone that I have now solution to import 3D lines/arc from C3D to Trimble Access to be able to stake them out. 

The solution is to export it as 3D lines/arc in dxf format not feature lines/arc as I did. Now I can see the lines/arc in Access and stake them out in 3D. The curves will be a little bit rougher as AutoCad will split the curves into sections and make a line for each section instead of arc. In my case it is fine as I'm using this to stakeout site layout, roads and walkways. But at least I can now stake out lines/arc in dxf format and with elevations. Big relief for me.

Helgi Valgeirsson 

Mike Tartaglia posted a quick video earlier this week on Autodesk Trueview 2021 - that now aloows you to explode the AECC objects and bind XREFs and save a new DWG file. That looks like that may help those of you that do not have Civil 3D that are seeing these problems. Could someone test that out and let us know if it solves the issues on files that you know you had problems with in the past?

Here is the video link Click Here

Alan

No way Trueview lets you explode AECC  now??!!

Following this. I really don't want to have to buy Civil 3D as i get too many AECC files form engineers. And their hours never really jive with ours! haha 

Thanks Alan for everything you do!!!