Re: 2024 topography - cut is fine, what about fill?

amarkovi · ‎04-21-2023

I understand the advantages of the new way of manipulating the topography, however pads were a much quicker solution in modelling a terrain.

Prior to 2024 if you wanted to "dig" a part of the terrain you made a shape in plan view and placed it at a desired height - cut or fill it did what it needed to do - for example, on a sloped terrain you could have half of the pad in the cut and the other half filled, all in one action.

Now in 2024 you have to create a void to cut part of the terrain, and then model the filled part separately. And if you have a simple shape of the building in contact with the terrain it's a few points (you still have to align each point two times to get it exactly to a corner, for example). However if your foundation has a more complex shape, the only solution is to place a whole bunch of points and then micro-position them? Is there a quicker option to create fills?

This new workflow, it seems, is just so time consuming...

Also, it is cool that the new topography "wraps" around the foundation of a wall, however that representation is not accurate. Revit will subtract the volume of the wall and its foundation from the total volume of the topography, however in real life the digging (cut) would be bigger than the volume of the concrete, and then there would be a fill on top of the foundation. The total (net) amount of earth will be the same, the net cut/fill number in Revit - however in a bill of quantities the digging and filling are two different works...

Like I said, the new topography tool certainly has some advantages - but I sometimes wonder if developers communicate with real users when making decisions.

barthbradley · ‎04-21-2023

@amarkovi wrote:

Also, it is cool that the new topography "wraps" around the foundation of a wall, however that representation is not accurate. Revit will subtract the volume of the wall and its foundation from the total volume of the topography...

Switch Join Order

amarkovi · ‎04-21-2023

The wall (and foundation) cut the terrain just fine, and the net cut/fill is accurate. However this is not how real life construction works - I mean this way you can get the volume of earth that has been removed (initial volume - new volume). In real life you would have to remove a greater amount of earth, build the wall and then fill up the remaining hole.

I have attached a diagram:

1) is what Revit does A (terrain) - B (wall) and you get X which is the volume of the wall that is in the terrain.

2) is how it really works: A (terrain) - B (excavation) + C (fill) and you still get X, however now (in BOQ) you have exactly how much you have to dig and how much you have to fill

This new option might work well for a tunnel or to make a nice looking drawing, but it is not much help in the whole parametric world, in getting quantities of the model you are building.

barthbradley · ‎04-21-2023

@amarkovi wrote:

In real life you would have to remove a greater amount of earth, build the wall and then fill up the remaining hole.

Yah, I know perfectly well how it's done in real life. A hole is dug deep enough and wide enough to accommodate forms - by eyeballing it. After foundation is set, then the hole is filled. Sounds like you want Revit to calculate the exact amount of earth moved by the "eye-baller". If so, then you need to model it by eyeballing it yourself.

Maybe, I'm misunderstanding what you are trying to calculate, but Revit is giving you a net difference only between 2 phases of construction.

barthbradley · ‎04-21-2023

...to do what I think you are saying, you would need a phase/condition in the middle of those 2 phases.

Mike.FORM · ‎04-21-2023

Technically this can actually be done with the new toposolid tool since you can join one toposolid to another. This is how they show water infilling a pond or a lakeshore. The bottom of the water is removed by the toposolid it is above. Thus taking the shape of the shoreline.

First make your existing topo. Then do your graded region to remove all the land required for all the formwork and other required space to do the construction.

Then create a brand new toposolid to infill the space which was dug out and have your foundations and footings joined. Then you can join the 2 toposolids together (join order matters).

You now have the net cut to construct the building and the new additional toposolid would represent all the backfill.

barthbradley · ‎04-21-2023

Why would you do that? I would use graded region copies and phases. Phase 1 = Existing Topo. Phase 2 = Excavation Work. Phase 3 = Backfill Work. No?

Mike.FORM · ‎04-21-2023

That is how I would do it also, However if you do not want to introduce a new phase just for the excavation work it can be done how I described.

Either way though I would leave it up to the contractor to figure all that out anyway. Some can work with less space some need more. Its up to them how much cost they assign to that work when they price or bid a job.

All comes down to Ways and Means.

barthbradley · ‎04-21-2023

mpukas · ‎04-24-2023

Back to part of the OP's original question, what's the best way to add fill when a slab-on-grade is above existing grade? Model-in-place a new toposolid extrusion and join it to the actual site? Or, add new points?

Also, using the method of two linked files - one for building and one for site - the toposolid in the site file will not be cut by the foundation walls and footings of the linked building file. The toposolid graphic fill pattern is overlaid on the foundation wall and footing graphic fill pattern. I had to create void sweeps for every foundation and footing (in this particular project on a sloped site, my structural engineer has several footing sizes and depths and walls thicknesses). It's a lot of extra PIA tedious work. And, as expected, Revit freaks out over some void extrusions overlapping, and not others, so I had to fiddle and fiddle and fiddle with them to get them to play nice and make Revit happy and not want to delete them for no explicable reason.

Toposolids are creating a lot more headaches, frustrations and extra work than the programers/coders/developers planned.

amarkovi · ‎04-27-2023

This a great way of dealing with backfill, thanks, never thought of doing it that way.

However I still have not found a way to do a quick flat surface (the pad in 2023) which would automatically create both a cut and a fill part of the topography - like in the attached image (this would be a surface to place a building on a sloped terrain).
With pads this takes seconds: you outline the shape and place it at the desired elevation - done.

Without pads in 2024 you have to first create a void and cut it from the terrain, and then you would have to model the fill part by placing a point at each corner of the slab/pad?

Also would it be possible to create the vertical part of the fill? Having two points in the same X,Y coordinate but different Z coordinate?
It just seems a lot more work without pads.

barthbradley · ‎04-27-2023

I don't deny that it is different from a modeling perspective, but from a construction perspective, it makes more sense. We are now literally able to remove and add volumes of earth. Frankly, it's been on the wish list forever. Autodesk finally came through. We got our wish. Learn to love it.

P.S. Regarding modeling vertical faces in Toposolids; model them the same way you model vertical faces in any geometry - by joining solid/void geometries together in the correct join order using Join Geometry.

Paulo.daRosa · ‎06-28-2023

I'm just trying to get a simple cut/fill schedule going. I create a graded region and make mass voids to subtract from it and the cut works out great. When I need to fill some earth, I create a topo solid and join to my original. The fill is added in my schedule however there is a large cut quantity that is also added even though I'm only filling. Any advice?

barthbradley · ‎06-28-2023

@Paulo.daRosa wrote:
I create a graded region and make mass voids to subtract from it and the cut works out great.

Mass voids? You sure about that? Don't you mean Solid Mass?

Regarding fill quantities being reported when you are cutting the Toposolid Graded Region Copy with a Solid Mass; that doesn't make sense. Are you sure the Schedule is reporting the cut/fill properties of the Graded Region Copy?

Post your file if you want us to look into it.

Paulo.daRosa · ‎06-28-2023

Admittedly I'm new toposolids. I've researched some and I'm creating in-place mass voids and then cut geometry to calculate the cut of the toposolid. That's working although tedious. You can see I've added a toposolid and used split surface to add some fill. If you check the cut/fill schedule, you'll that a bunch of cut was also added with those. Thank you.

barthbradley · ‎06-28-2023

Everything looks right on my end.

pdarosa · ‎06-28-2023

Those last three toposolids from the schedule are the stairs and two raised planters you see if the 3D view. They are strictly fill. As you can see in the schedule, they calculate a large quantity of cut which throws my net off. I asking to know how to calculate the fill accurately. Thanks