Changing profile and surface elevations when modifying datum

[Julien1992]

 Hi,

I'm hoping someone can help me as I am beginning to lose hope right now. I have a point group that I have used to create a surface as well as a profile. The original elevations of the points in my file were in the 500m range. Now I want to change my elevations in order to have them at their true elevations, about 250m lower. 

So I right clicked on points (in Prospector) and substracted 240.071m from all the points in the file, while in the "Datum" command. Now all my points are 240.071m lower, but my surface and profile elevations remain in the 500m range.

Could someone help please?

Thanks!

[MMcCall402]

Did you run a surface rebuild?

Select the surface in ToolSpace, right click and choose Rebuild

[Julien1992]

Yes, but unfortunately all that does is create an opaque gray area where my surface should be, and the elevations don't change..

[Jay_B]

Did you first right click on the "Point Groups" heading in Prospector & choose UPDATE?

[MMcCall402]

"Opaque", look closer, it may be contour lines so close together that they appear solid.  There may be something else defining your surface that also needs an elevation adjustment. (creating a 240m spike in your surface)

[Julien1992]

Yes and that also seems to do nothing, my big concern here is the profile, seeing as I have it set to "Dynamic", I thought it would update the elevations automatically?

[BushW]

Hi @Julien1992

I see that you are visiting as a new member to the AutoCAD Civil 3D forum. Welcome to the Autodesk Community!

I also suggest updating your points group that you used to build your surface. Select the points in Toolspace , right click and update point group.

Please review this AKN article To Change the Elevations of Points and video which will help you manage points and help edit and update your surface model. Hope this helps!

Please select the ‘Accept as Solution’ button if my post solves your issue or answers your question so, other Community members may benefit and thank you for doing so, and I'm here to help.

[BushW]

Hello @Julien1992

Can you post your drawing for review?  

[Julien1992]

Sure, here it is.

Thanks

[Jeff_M · Accepted solution]

The surface in the dwg is not using the Points (no PointGroups assigned) but it is using breaklines which are all at the old elevations. Move those using the Displacement method, then add the PointGroup, and all should be well.