DXF, Feature Lines & Staking... Oh my

[n2itive]

Our survey crew would like to upload a dxf file into their data collector in order to stake out linework such as curb & gutter with elevation. They have given up on using stakeout points as a standard procedure long before I arrived (being the cad guy I just figured everyone used points for stakeout) and up to now they would just use the 2-d linework and manually calc elev on their own. From what I understand our RLS didn't "trust" the data collector to use elevation for staking. Now that we finally talked our RLS into "trusting" the data collector as far as using elevation for staking we are running into problems with our feature lines when exporting to a dxf file. As you may or may not know when exporting to a dxf file it explodes our feature lines into lines, p-line, and arcs. Feature lines that have different elev & no curves turn into regular line segments and they still have the correct elev on each end vertex. Great. Featurelines that had the same elev for all vertex turn into a polyline with no elev or a whacked out elev. No Good. Featurelines that had a radius turn into polylines and/or arcs (I don't know what it's using to determine this) but either way the elev is zero or whacked out once again. No good!

So, is anyone using a dxf file in their data collector to stakeout linework with elevation? If, so what is your procedure? What am I doing wrong? Any other suggestions

Further more I find it absolutely ridiculous that... oh never mind, it does no good to complain about the complete lack of transparency between C3D, surveyors, and surveying equipment.

I have tested the dxf file with both C3D 2011 & 2012. I have not tried it with 2013, maybe that has changed? Our survey crew is using a Tsc2 data collector.

Any thoughts would be much appreciated. Thanks

[mathewkol · Accepted solution]

DXF files do not support feature lines as DXF is a very old format.  But they do understand polylines and 3d polylines.  Feature lines with no curves can be expoded into 3d polylines quite easily,  Feature lines with curves cannot be converted into 3d polylines because 3d polylines do not support curves.

Your feature lines cannot have curves if you want to lay out using DXF informaiton in your collector.

I think you'd have better luck exploding curveless feature lines before turning the file into a DXF.

Exploding FLs with curves does result in a tesselated 3d polyline, but I'm not sure what controls the tesselation.

If you NEED curves, look into making them alignments and profiles and then using Trimble Link to export these to the collector.  Yes, this will be different and perhaps awkward, but DXFs don't support FLs nor do 3d polylines supports curves.

[n2itive]

queer!

That was our crew chiefs response... I thought it was quite funny

Thanks for the explanation though. I did have a quick discussion with them about creating alignments and profiles and this seems like a possible route. Like you said our problem really is just with the curved areas. Unfortunately our parking lot has to have a 2' min radius on all corners in addition to the curve entrance.

Thanks again for the explanation and suggestion!

Shane 

[sboon]

We have had some success with exporting surface data to dxf files for use on the data collector.  We are running TDS software - which was bought out by Trimble, so it's possible that the newer software works the same way.

The process we use is to change style of the design surface one that includes the TIN lines only, and then export the file to ACad.  Open the exported file - the TIN should now be a set of 3d faces.  Clean up the drawing and purge everything possible so that these faces are the only objects in the file.  Finally, save this file as an R12 dxf format.

Upload the dxf to your data collector and see what happens.

[dgordon]

a dxf file with 3d faces in it can also be converted to a dtm using the survey data connection link.

which is how we get tin's into our older data collectors.