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I have started using the Utility feature to estimate trenching and backfill quantities however I am running into issues where I am doubling up on quantities where trenches overlap. Is there a current function in the utility module that deals with overlapping trenches? Ideally I don't want them in a common trench because I still want the material between them as I would not be excavating that out. Does Trimble have a surface trimming function or what would be the best method to deal with trenches that are far enough apart that they should not be in a common trench but the side slope in each trench surface intersect?

Brittany - there are a couple of answers here I guess

1) If you are doing Takeoff Calcs, and you want to keep the 2x Trenches separate then there is no "Merged Trench" solution for Takeoff Calcs. Where the two trenches come together, you could use a different Trench Template to model the "Combined Trench" in the section where they interact. You can apply different Trench Templates at different stations along the trench and that is gong to give you the best solution I guess when it comes to Takeoff. For example You could just do a Vertical Wall on the side where the two trenches merge together and the normal Trench with sideslope on the outside - and do that for both trenches - that will give you the right quantities for Excavation and Backfill materials.

2) If you need to create a combined surface model from the trenches that you create, then you can use the editing commands to clean up the Linework of the Trenches to make a combined Surface that you could use to run the machines, however that will not affect the Takeoff Computations in any way. If you are going to do this, I would make a copy of all the Trench Linework and make an all new surface from that linework that provideswhat you need for the machines, since if you refresh the Trenches the Linework will keep getting re formed etc.

I hope that this partly answers the questions - if you want to share the trench model with me I can take a look at what you have to work with and can look at how to best create the additional trench templates to meet your needs.

alan_sharp@trimble.com

Alan

Thanks Alan for getting back to me. I have a follow up question regarding this. If I am going to manually clean up the line work where the surfaces intersect,  is there a command that does the surface trim. I am familiar with Autodesk that does have a surface trim command (similar to a line trim command) where it trims at the intersection point. With trimble it is very difficult to “trim the surfaces” or create a line at the intersection point. Is there a method to find this intersection point of the two surfaces?

Regards,

Brittany Koebel, E.I.T.

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You can use the create sideslope command to project a sideslope from a line to a second surface and it computes the line you need - you can then add that line into the surface you are building up.

The create surface tie command also does something similar but I prefer the create sideslope command for all those kinds of details

If you get stuck, share the parts of the model with me as a VCL file and I will record you a video of the workflow that I would use to do this

There are many modeling "Tips and Tricks" that over time you get to learn - I wish I could just pour them all out on a table for you but each scenario is different

I would like to take a look at your merging Trench issue if you could share it as that is a tricky problem to solve (but doable) and I haven't tried that personally but could take a while to look over it and give you some ideas

When playing with surfaces - I try to do it with linework and then form the surfaces from the linework - so using the Trim, Extend, Clip, sideslope etc commands would.

typically be where I start and then try to compute the surface intersections using sideslope etc

Alan

Sent from my iPhone

Brittany

Which Autodesk Civil 3D command specifically are you referring to that you say allows you to "simply Trim the surface". I had our resident expert on Civil 3D take a look at this in C3D and he does not know which command you are referring to.

What he showed me in the form of a video was the ability to add a boundary to a surface and edit that boundary to "trim back a surface" and TBC has an identical function - the only difference that we can see between the two is that TBC uses its boundary as the physical limit of the surface whereas C3D seems to remove any triangle that crosses the boundary leaving a "Smaller surface" than the boundary area - TBC basically computes new points where the triangles cross the boundary and re triangulates accordingly - see the video below

What am I missing here - please advise so I can assist you (a short video would be helpful

Alan

Alan,

I think this is what Brittany is referring to. In AutoCad's command line it is called: SURFTRIM. C3D 2018

I have no idea how this function works but if I had to guess I think it is probably some combination of:

• TBC's surface edge breakline
• appending the intersection
• combining the two
• then adding it as a boundary to the surface you are "trimming" 

I agree that this would be a useful tool for overlapping trenches, especially for machine control. I can also think of several other cases where this would be extremely useful, such as subgrades. The one downside like you mentioned is that this would not update the quantities for takeoffs. 

I agree that the side slope command has been a great addition for situations like this but it is not necessarily the easiest when things vary.

For instance:

• stockpiles
• dentition ponds
• Rock Faces
• Design type work

The video below shows a couple of examples that I came up with this morning.

I think we should discuss after PUG in April - The New Sideslope Capabilities (in Corridors and Sideslope Command will help a lot as you will be able to add any surface as a Material Layer or use as a Target Surface, and then you can Sideslope to a Material Layer and the Material Layer does not have to be above or below the Hinge point if you know it is a Cut or a Fill specifically - You can also have Slope and Max Depth / Max Width Tables for all elements you are trying to design so I think you will find it a lot easier to model these types of scenarios.

I will ask Mike to look at Trim Surface in Autocad and get his comments - he has looked at this since Bethany's first post - and it really did not look like that would help much for this type of work - however he may not have used that specific command - I have to go back and look at his videos

I am not 100% clear from the videos above what exactly a Surface Trim command would do for you - in Autocad it is cutting one surface back to another surface - but it will give you steps in our world - it wont force a nice tie shape / slope between them etc. which is what I think you want. This would be a good discussion area for the PUG Class I think to identify the real requirements here.

Alan

I ran into this problem last week. The way I was able to calculate what the over lap was. I'm assuming they're running parallel to each other.

1)Merge the two trench surfaces with the option - Keep maximum option.

It will generate the above surface where they overlap. You can then run an earthwork report to whatever surface you have on your target surface set to. This should give you that triangle information.

Great to see Erik

Alan

Hi, 

I was just thinking that since it is possible to find the isopat line/ intersect line between the trenches (surfaces). Then this line can be copied to the natural surface directly above. Now use these two line as members of your trench surfaces. This method will only create an intersect line where they meet and won't need to do section by find the trench overlaps. You may be able to not delete the existing trench lines also. I have not tested this, only theory.