Trimble Business Center

Does anyone use the Overexcavation tool in the Take-Off module?  On my workstation it bloated my take-off model from 17 mb to 257 mb.  Curious if anyone else has experienced this.  

I would have to look at the data to see why that was - If the 17MB file had an OG and FG surface with or without Subgrade Adjustments, I would be surprised if the additional size was caused by the Overex surface model - you could set that to Rebuild Method Show Empty and save the project to see if that does reduce the project size back to 17mb - I would like to get the file to take a look at to see what is happening there if that is the case.

Alan

were you able to get my file?

Microsoft OneDrive - Access files anywhere. Create docs with free Office Online. 

I have it and I will be looking at it this PM

ALan

On Wed, Sep 23, 2020 at 7:21 AM thomas@byardconstructionllc.com <

It does the same thing in anytime we use this tool as well.

So Thomas

I have analyzed your project by Creating all of the surfaces first and saving the project and seeing what the file size is and then progressively turning off surfaces by setting their Rebuild Method to Show Empty - then saving the file again to see the effect on the File Size.

You have to look at the surfaces first to see how many triangles and vertices there are in each surface because this will have a major factor on the file size. What you will see in your Project are that these are the Number of Triangles and Vertices and Independent Vertices in Each Surface

Your CF Map is between the Adjusted OG and the Adjusted FG Surfaces but your Isopach is dependent on the Adjusted OG and Overex surfaces - so it is the combination of the Overex and the Isopach Surface (the two largest surfaces) that cause the bloating of the file, because without the Overex Surface you dont have the Isopach surface because it is a dependent object. 

Add those two objects together and you have 6.4 million triangles and 3.2 million vertices and 3.1 million independent vertices compared to the whole project combined which has 9.1m Triangles and 4.6m Vertices and 4.2m Independent Vertices - so you can see that the two surfaces combined account for ~70% of the Surface Based Data. 

After I turn off all the surfaces - the residual project size is just 7-10MB. So the remaining 245MB is all Surface Data. Take 70% of that and that gives you 168MB which matches what you are seeing.

So to reduce the file size you can eliminate the ISOPACH surface which takes out 111MB of the size. 

The CF Map accounts for 53MB of the file size 

The Overex accounts for 70MB but because you have it linked to the Isopach Surface it seems that much more because of the surface dependency. Below is a summary of the contribution to file size that each surface makes

The reason that Overex is so large is that it has to compute all of the intersections between all of the triangles in the source surfaces (OG with TS Adjustments and Demolition) (209000) and (FG w/ Subgrades Removed and Topsoil Absent) (140000) (and for all of the closed lines that you are considering) - this creates a large multiplying factor for the Overex surface in terms of the number of vertices and the resulting number of triangles.

Hopefully this explains what you are seeing and gives some ideas on how to mitigate the file size creep. These are extremely complex computations and we have to create all of the additional triangles in order to get the numbers right.

Is there a way to set it to not save the isopach all the time?  As you mentioned, it can easily be a very large amount of data and I rarely have any use for it after the earthwork quantity has been computed.  I thought turning off the option to save intermediate data in the earthwork report options would do it, but it still saves the isopach.

As a follow on to our phone conversation, I started to look at the Overexcavation calculations and alternative ways to compute this. Since the areas that you want to compute the overexcavation for are just the buildings, and they represent a fraction of the area of the entire project, in this case I would agree that computing an Overex Model over the entire site is "overkill" and is creating unnecessary amounts of data as a result.

You can compute the Overex surface that we discussed using the following method as an alternative approach

You said your conditions were as follows

1. You have to excavate at least 4' out from beneath the buildings areas. This is 4' below the lowest subgrade adjustment in the buildings
2. If the 4' below the buildings above is less than 1' below Original Ground with Topsoils Removed, you have to remove at least 1 foot below topsoil.

So the Overexcavation surface is actually a composite of the lowest surface of Adjusted FG - 4' and Adjusted OG - 1'.

1. Use the Offset Surface command to create an offset surface within each building area for the Adjusted FG - 4' and the Adjusted OG - 1'
2. Use the Merge Surface command to create a merged surface combining the two offset surfaces created in (1) using the Keep Minimum setting. This will create the Overex Surface required

Note:

I would offset the building lines by 0.01' inside and use those as the boundary areas for the Offset Surface, that way you will eliminate the vertical walls around the subgrade adjustments in the merging operation which will result in a better overex surface.

The video shows you how to do this process

Alan