CREATE A SECOND DATUM FOR ROAD CORRIDOR

[Westhills]

Back in LDD sections were simple. I would create my typicsal secitons with several datums representing finished ground, sub base, excavated surface etc. 

In my c3d model I have creted my typical assembly for finished grade and it works great. Our site is alomost all bedrock that requries blasting and now I want to create a second "datum" for my corridors so I can calculate blating quanities for my entire site. its in the order of 250 000 cu.m. of blast so this is important. I know there are a hundred ways of doing this and there is probably a better way. However I have to work within my familiar skillset to actually get things done aswell. All I need to get out of this are cogo points for my new datum into mydrawing so I can merge them with the points I have already created for the non corridor areas. Then voila, I have my blasted surface that I then can use to calculate a volume surface.

What I need is some guidance on creating this second datum. See the attached image where i show my assembly, finished ground subassemblies and below the second datum(or sub assembliy) I need.

Many Thanks

[Westhills]

Ok so I created another corridor for my blast surface starting ith a new assembly, then add a vertical link to get down to my reference point on my blast surface, then used two linkmulti for left and right to create the surface/datum i needed.  I now have points created for my finished ground centerline that need to be filtered out when bringing in points. I do alot of this sort of thing and would really like to hear of any better methods. I would really like one assembly with multiple datums.

Thanks

[Ed.McGriskin]

Depending on the level of detail in your sub assemblies, it may be possible to create mutliple surfaces from one corridor.

For example, with a generic pavement structure for a roadway, you can create an Finish Grade surface using the Top Link from you assembly and a Subgrade surface using the bottom link of the granular material. This way, both surfaces are tied to the same corridor and will both update with any edits to the corridor.

[mathewkol · Accepted solution]

Your section is very easy to do with a single corridor. You've actually done it already except you've split into 2 separate corridors. Just add the same subassemblies to a single corridor and you're done.

You would then create 2 different surfaces, chosing different link codes for each surface.

The trick is to change the names of the link codes for the generic links.

[Westhills]

Thanks Matt

Makes sense enough.