Cut Fill Volumes under specific elevation?

[isaac.ernst]

Hi All, 

I have a situation where I need to balance Cut/Fill below a certain elevation (10.90m) - the majority of design levels for the site sit higher than 10.90m and the existing surface sits lower than 10.90m. 

To do this currently I have extracted user contour of 10.90m from my design surface, created a 2 separate surfaces where the area inside the 10.90m contour is a flat pad at 10.90m and the other surface is simply the design surface with the area which exceeds 10.90m in height hidden - I've then pasted these together to create a surface that I can use for volume comparison to the existing surface. 

Does anyone know of an option that would skip this step? i.e. a bunded surface on volume dashboard or similar that only analyses the surface below a specific RL? Does something like that exist? i.e. I could just do a normal comparison surface between EXIST and DESIGN but only tell it to analyze under the specific RL of 10.90m? 

Thanks very much in advance for any help! 

[nkiakas]

Hi @isaac.ernst 

From what i understood, you want to calculate the earth works between a "normal" surface and a plane surface.

To create a plane surface, no need to add user contours. You need just a closed polyline with your desired elevation in your plane surface boundary and add this polyline as break lines

Regards

[neilyj666]

@isaac.ernst I think the workflow you are using is the only way to achieve this.

[isaac.ernst]

Sorry I probably didn't explain it as well as I would have liked with just words. I don't think its that simple unfortunately (please let me know if I am wrong though) 

The model below is the Finished Surface Model (you can see steps in building pads etc) 

Given that there are portions of the design that sit under the RL 10.90m I still want those included in the volumes as well so the surface I have created to check volumes under the specific RL of 10.90m looks as below - you can see the large flat pad at 10.90m but still a good portion of the design sits under 10.90m with varying levels 

Profile view below to try and demonstrate a little clearer as well 

Would a Plane Surface assist? 

[fcernst]

Add a design surface build definition to not use elevations greater than 10.9.

[isaac.ernst]

Hi Fred - great last name! Haha. 

Appreciate the suggestion and sounds like it might work really well - I've tried to do this but it seems to be triangulating incorrectly (see below) - essentially I would want it to stop at 10.90m and any elevation over 10.90m would be replaced with 10.90m level which I was hoping was what your suggestion would do. At the moment it seems to be not including anyhting over 10.90m and triangulating itself which is not really what I was after.

Am I missing a variable somewhere that could tell it to do this? 

[fcernst]

Can’t see what it’s doing.. saying it’s nonsense?

[isaac.ernst]

Any better now? Screenshots should be attached?

[fcernst]

Sorry I can’t see it. I’m on my phone now

[fcernst]

You still may want to just sleep

on it and see if excluding this data is at all helpful for the specific balancing exercise. 

[neilyj666]

@isaac.ernst I've been doing this type of thing for years and there is no simple way of achieving it—unless I've missed something obvious.

Remember that Volume surfaces are only showing relative levels of the base and comparison surfaces rather than an absolute level above your datum

[dkennedy]

create an alignment through the site, and cut sections where needed, and use subcriterias to generate the necessary hatches for your average end area volume calculation