Trimble Business Center

I had to adjust an old mode lthis morning that either myself or one of my colleagues prepared 4+ years ago. I did not have the original data but I did have the ttm that we provide to the field crews. I needed to adjust the model because there were some field changes made on grades and I needed to accommodate for these in our phase 2 ties. 

What is the best way of going about this?

My process:

1. Imported ttm
2. Imported spj from field crew
3. Used a label point style to label points and visual highlight elevation differences from the installed surface (field mapped) to the model surface 
4. Created breaklines for the new tie
5. Created boundaries around these areas
6. Used the explode surface TML
7. cropped out the old data
8. added the new tie in data

This worked but it seemed slow and the exploded surface is a resource hog. Has anyone found a better way of doing this is the original data 3D data isn't available?

Typically with our field models, I provide the 2d linework un-elevated and the modeled surface. If the linework was elevated this may have been easier. 

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This seems to always be one of the most difficult things to do as a revision.  I always make it a practice to include the 3D linework just for this reason.  Your workflow seems to be the best approach and I would love to see some responses to this thread with more ideas.  It is usually hard enough to revise a surface model when you have the original data, much more difficult when all you have is the .ttm file.  I like your use of the point style labels to see where a point is different from the surface.  On another note, I used to be a field guy, so the 3D linework was almost more valuable to me than the surface, so I can't really see ever using a model that does not have 3D linework.  I know everyone has their own persprective, but I always found more information was better than less.

I think the use of VCLs in the future with Siteworks will help address this issue because I believe by default it exports the 3D data that composes the surface. Similar to a LandXML but smarter.

I agree the 3D lines are useful but it is always hard determining what is valuable and what isn't. The lay sorting in SCS900 also was not sorting alpha-numeric and made it hard to turn of specific layers. This has since been addressed in Siteworks and is a lot easier to turn on and off unnecessary linework.

I have found it is easier to export the 2D linework and drape it over the surface.  We are still learning but at the moment this seems to work well and we don't get too many issue with user missing data.

I may pick your brain on some modeling ideas at another time.

I would rebuild the tie in portion of the model from scratch with linestrings and spot elevations as needed using any field shots. Build that smaller area as a new surface then merge surfaces to get it back to one surface file. If the new surface needs points to match the existing surface then just use the right click elevation of surface option or whatever that feature is, either spot elevations or when tying in with a line, using the vertical part of the linestring. That way when you merge surfaces the tie in shouldn't be too dramatic.

I agree with the other points about using 3D lines, being out in the field it's much nicer having the 3D line, even if the data collector handles surface at 2D line. Especially when staking vertical changes in a curb or EP you can see those points and stake them as to not miss any grade changes. 

All my models included 3D linework for proposed design. This make it easier like Mike mentioned for revisions and in the field. My template in TBC has layer groups set up for the machine file export and a rover export. This way I can send out the 3D line work that is labeled and joined together for all the interior curb islands as an example, for layout with the rover, even though the surface blows right thru them for the machine.

How do you address arcs? Arcs become corded and you can not create radius points for them anymore in Siteworks? 

I would rather not have to create stakeout points for all of the arcs in a project because I find those tend to be user specific. 

Still on the subject of everyone has different tastes, I have been very cautious about draping because it is very easy to get something wrong in areas of quick grade changes like the back of curb.  I took a model I built, long enough ago that I can't remember which one it is it anymore, that I draped the 2D curb line onto the surface I built.  Because of the cording of lines and maximum sampling distance, my line did no drape perfectly at the back of curb.  This caused my back of curb line to have dips in it because it did not perfectly match the triangle breaks that the surface made, even though the 3D line that the back of curb was built on was copied from the 2D curb line originally.  Because of this, I usually only drape at tie ins or an area where the grade breaks are not that extreme, unless I have no other choice

I have not seen what Siteworks does with VCL Files Pat but theoretically if it is supporting VCL properly it should handle 3D arcs now if you use VCL as the transfer mechanism - I will have Steve DiBenedetto comment here and will let you know what I find out

Alan