Using XRef'd Lines as Breaklines for a Surface

[camden.n.dean]

Hi all,

I am doing some volume calcs, and think I've hit a software limitation, but would like the experts' input.

My volume surface will be comparing my Design vs. EG. I will then be bounding the volume surface based on the different sections of the design. See below figure and caption for a concrete example of what I mean.

Fig. 1. I will be comparing a design surface with varying depth (59' for A, 60' for D1, etc.) to an EG survey. I then want to have bounded volumes for A, B, C, D1, etc.

Easy enough.

The problem is this: I want to be able to move the boundaries in the future and have everything update to the new boundary linework. I thought that maybe I could do this by xrefing the linework into my 'Design Surface.dwg' to use as breaklines and into my 'Volumes.dwg' to use as boundaries. This doesn't seem to work since the xref is treated as a block, and I cannot select the individual feature lines from the Xref to use for either of these purposes.

This wouldn't be a problem if I could keep everything in a single file, but this needs to be done in multiple files for a plethora of office-specific reasons.

Is there any hope of having a dynamic link to my boundary plines in Civil3D, or do I have to just copy them around and chase the dragon when/if the boundaries get updated?

Thanks,

Camden

[m_kingdon · Accepted solution]

I am slightly confused when you mention break line and boundary lines.  I believe these are different entities.

If you want to draw bounded areas in one drawing and have them data referenced into another drawing in a way that you can do bounded cut and fill volumes I think it is possible if you draw these bounded areas with alignments that are in a site.  Areas that is closed and surrounded by alignments that are in a site will form a parcel and a parcel can be selected as an entity to generate a bounded cut and fill region.

But to be honest, I think this is more work than it is worth.  Is drawing a few boundaries whenever an xref is updated really that much work?

[camden.n.dean]

Hey Mike, always love getting input from you!

"I am slightly confused when you mention break line and boundary lines. I believe these are different entities."

You're right that break lines and boundary lines are different entities. I am just using (essentially) the same feature line for both purposes. Each area has a different elevation, so I drew a closed feature line for each area. Then I added those feature lines as break lines to my surface. I just glossed over the fact that we aren't properly modelling the transitions in depth, so I could just use .01' offsets of the exact boundaries for my break lines. Using the offset feature lines as the boundaries for my volumes would be totally fine. TLDR; you're right, but they are the same line in this task.

"But to be honest, I think this is more work than it is worth. Is drawing a few boundaries whenever an xref is updated really that much work?"

You're again right that it isn't much work to update the boundaries in a drawing. My real concern is that I'll have to chase the change through lots of drawings since our workflow creates lots of DWGs all using the same linework. This makes the work explode for larger projects with lots of DWGs each with lots of boundaries . Having a dref/xref that could be used for the boundaries (and preferably even the breaklines for the design surface) would eliminate that concern, and make sure that every drawing is on the latest linework. TLDR; right again, but our decentralized workflow would benefit greatly from a dynamic link.

I'll look more into your idea of using parcels! We don't use them for anything at the moment (we mostly do nav channel and beach work), but this seems like a promising solution!

Thanks a bunch for taking the time to share your wisdom,

Camden