Data referencing from alternative grid layout

[Anonymous]

Looking for a solution to an ongoing issue we have with Civil3D data on different grids.

All our alignment design for major infrastructure projects is traditionally produced on a local grid - this local grid is not arbitrary but the parameters match the UK's Ordnance Survey grid (US equivalent would be State Plane Coords) with an Easting, Northing and combined scale factor.

Despite almost all our design work being done in this Local Grid, there is some Civil3D data that has to use the OS grid, notably that produced by our geotechnical team.

So . . . .  what I need is a solution that the strata surfaces created by the geotechnical team in Civil3D and on the OS grid, can be data referenced into the rest of the project on their "local grid".

We cannot move the geotechnical data - it has to remain on the OS grid and not the local grid.

I know how to produce the grid transformation, in Edit Drawing Settings, we already use that for setting out labelling - but how can we use two different alternative grids to data reference data between each DWG?

[rl_jackson]

I'm not exactly sure what OS Grid is but to the best of my knowledge you can only use a single system. If this OS Grid for the geotechnical work can be changed that my be your best option for all the data

[Anonymous]

We cannot change the grid system (UK national Ordnance Survey) of the geotechnical data; most of it is sourced from borehole surveys on the project site, the remainder is from the The British Geological Survey database, which is of course on OS grid.

Putting all other design data; alignments, drainage, structures, etc. on the OS grid is not acceptable (too long to go into the arguments here), so I need a method to have one set of data in local, and the other in OS grid, but able to data reference using a northing/easting "shift" as if it were a traditional CAD Xref.

I honestly don't know what real use the grid transformation function is in Civil3D/Map3D, it really only deals with points and subsequent point labeling. If it could resolve the issue of allowing you to overlay or data reference disparate grid based data then it would be a really valuable tool.

[rl_jackson]

Well here is a thought.

You could look at the standard grid (Cartesian System) as your geotechnical system. Then set your drawing to the local BGS grid and St a transform utilizing the Transform Tab.

Now by doing this you would need to have to different import/export point formats. One for NE and one for Grid NE (BGS). This would allow you to label and import/export in both systems

[rl_jackson]

Now let me add one more comment to the above statement. Your drawing will be on the Cartesian System. But it will give you the ability to provide information and points in both systems

[Anonymous]

Thanks - but as I said Points aren't an issue, we have used that very method you describe for setting out, but our geotech team use the HoleBASE extension for Civil3D, creating surfaces of strata - that is what we need to data reference.

[tmachado]

Hi @Anonymous, if you want to transform the surfaces location LandXML can be the solution for you.

Take a look at this short video that I created for you https://www.screencast.com/t/hu0RTfSWEJdt

[Anonymous]

Tatiana - thanks, that is an interesting workflow, and I will probably use it on other requirements, probably GIS > AIM data.

However, that is creating a duplicate copy of the same data on a grid shift - which is precisely what I am trying to avoid. I could have just "inserted" the DWG applied the grid shift (and the scale which is 0.999790629657) to create a duplicate of the Geotech surfaces in Local Gird - and vice versa; a minus grid shift with a negative scale factor for all the other Civil3D data for the Geotech team to use in Ordnance Survey grid.

Effectively I would have two datasets on the same project, Local Grid and OS grid - which is poor data management and almost impossible to validate when there are amendments, route optioneering, etc.

There has to be a better solution. 

[tmachado]

I know what you are saying unfortunately sometimes you don't have other options, precisely last year I worked on a very big project with Disney and they work on their own grid so to coordinate everybody and be able to work in IW as well it was a royal pain and an incredible amount of duplicated data.

[Anonymous]

Agreed - I don't know why Autodesk haven't addressed this issue, it isn't new, and quite clearly is an ongoing issue on many big projects - I had previously been working in the middle east on oil refineries, and there you have UTM grid data, but also "plant grid" - any infrastructure and building elements of the project must be designed on UTM, but also tie-up with the plant design grid.

Having the ability to grid shift, rotate and scale from a data reference DWG should be straightfoward?

[tmachado]

Post it on the C3D Ideas station and I will gladly vote for it

[Anonymous]

Tatiana - I've posted it, cheers.

https://forums.autodesk.com/t5/autocad-civil-3d-ideas/data-references-to-have-an-insertion-rotation-...

[tmachado]

Please share the link so we can all vote for it!