Dealing With Grading Site

[TerribleTim]

How do you guys deal with grading the site for a building pad? And how do you deal with that in terms of "phasing". I have a site that we are building basically 3 different buildings spanning 3 different phases. What I did was modeled an existing conditions model as my "base plan". I then linked that into a model for phase 1 and created all of our phase 1 stuff there. Same thing for phase 2, linked in phase 1 and modeled all of phase 2 in that one, so on and so on.

Here's my dillema. I had to create a building pad in the base model for each new building. Even though I set the parameter of the building pad to the phase it will be created, I still can't figure out how to get the site plan to show correctly. It shows the ground with this huge cut in it where the phase 2 building pad would be, even though I'm looking at it for phase 1.

Any ideas? Am I going about this totally wrong? How do you do this?

[patricks]

I think it would be easier for you to use the Phase tools, at least in your site model. Each building model could still be a separate Revit file, but you'll have to decide which file will host all your details and such. Or if the buildings aren't too complicated you might consider having them all in a single, phased Building model.

In the Site file I would set up phases for each Building construction phase. Set up your existing topo surface on the Existing phase, and then in a Phase 1 view start a graded region. Copy the points from the entire existing surface, grade as necessary, and place pads as necessary.

Next go to a Phase 2 view in your site plan. Start a Graded Region for that phase, copying the Phase 1 surface and grading as necessary. The trick here, though, is that it appears you will have to select your Phase 1 pads and set them back to Phase 1. For some reason when you start a Graded Region and tell it to make it like the previous one, it also changes the previous phase's pads to be on the current phase. A bit odd, but after getting it all set up your grading plans for each phase should appear correct, with no "holes" in the site where future buildings go.

[TerribleTim]

Sounds like I'll need to brush up on "Graded Regions". I've never done them before and I think I tried that with no success before going to the building pad method.

I already have separate phases set up for each construction phase. So if I follow what you are saying, I will end up with multiple topo surfaces in the model, each in a different phase and each only showing when the view is showing that phase, correct?

[patricks]

That sounds right. We usually show our Grading Plans as Show All so that both the demolished topo (dashed lines) and new topo (solid lines) show up.

[TerribleTim]

Thanks Patrick. Looks like my goal for today will be learning everything I can about graded regions and making this topo look right in each phase. Appreciate the direction and the tips.

[patricks]

Graded Region is the same as creating a toposurface. The difference is that when you select an existing topo after starting the GR tool, it will automatically demolish that existing so that you can create your new one, and the two will be linked such that it will report cut/fill volume data. You also get the option of creating a new surface exactly like the original as a starting point for you to modify (my usual choice) or creating a new surface by copying over the perimeter points only and no internal points. I would not do the latter unless the topo you're modifying is quite small and relatively simple, or you're modifying everything in that area.

If you have a toposurface that doesn't get changed, you might even consider splitting your surface out to only include what will be graded, and do a graded region of that area. The hitch there is that if the area to be modified ever changes, it's quite difficult to change the areas of the existing to remain and existing to be demolished portions of the topo, and likewise the new graded region perimeter.

[TerribleTim]

Good info there too Patrick, thanks. I have a topo that is quite large so I think I'm going to split it into a subregion that includes only the site itself, so I'll create the subregion picking the property lines as the boundary for that. Then I can create my graded regions of just that subregion.

Maybe this doesn't seem as complex as I thought.

[nancy.mcclure]

Tim, some best practice guidelines at our firm:

Overall Best Practices:
• Create the SITE model separate from the BUILDING model. Link them into each other Origin-to-Origin, but know there will be some manual coordination across Levels/rotation. This allows the site to be built/developed at a true north orientation (easier coordination with updating Civil files), and allows the building design to be reviewed for optimal site orientation for daylighting/shadows. (This also keeps each respective model file to a manageable size).

• Consider split surfaces along property lines of a larger area toposurface. This prevents altering grading beyond the property, and tracks cut/fill for the legal lot ONLY, rather than over an extended area. Each split off toposurface should have a Graded Region created to track it's cut/fill.

• Split surfaces cut a portion of the topo surface out from the whole, to allow for change of grading and material. It is then seen as a separate toposurface altogether, and can be deleted, grouped and linked out, etc. This is a good opportunity to develop grading options for a portion of a site, which can be swapped out by managing links. Final design link can be merged back into the site file.

• To track cut/fill, create a Graded Region BEFORE DOING ANY POINT GRADING. You will be prompted to copy only perimeter points, or all perimeter AND internal points for the toposurface. When to use which:
a) Copy all points (perimeter and internal) if the toposurface represents the entire site.
b) Copy only perimeter points if the toposurface is a portion cut away from the overall site, that will be evenly graded (building footprint)

• Use PADS during preliminary design phases - they create temporary 'excavation' areas without losing the original grade information. Pads are associated to Levels, so either create levels specific to key site elevations, or use offsets relative to building-associated levels. Pads cannot straddle/overlap between 2 split surfaces.

• Pads CANNOT OVERLAP. At all. Not even a little bit. Seriously.
When creating adjacent pads, use the PICK LINE tool to ensure no overlap to the previous pad. Do NOT use PICK LINE when creating pads adjacent to building walls, however, or you risk auto-deletion of your pads in the future, as wall positions change. NOTE: Curving pads adjacent to other pads WILL cause hairpulling and tears. Avoid these by following the final tip of this section.

• Consider creating a larger, single pad to depress the toposurface, and place FLOORS of a "SITE - Planting" or "SITE - Walk" type over them. You will have more flexibility to develop those features than creating them with Pads.

[TerribleTim]

Thanks for those tips. I still have a few items to work out I guess.

I originally tried using a building pad, but found that when I went back and deleted the pad, the excavated hole was still there and wouldn't go away.

I have now gone back and recreated my topo from scratch (not really, I had a 3D AutoCAD file so it doesn't take long. Revit rules!). I then created a Graded Region and told it to create a copy of my existing topo. I then put the building pads in that graded region topo. This seems to work better, but now I need to manage which one is visible in which phase. Even when I set the original one to be demolished in a given phase, it shows and needs to be hidden in each view. Just a lot of new stuff to wrap my head around, but I'm getting there. Thank you to all of you for the tips on this.

I also need to figure out how you guys deal with roads and parking lots in Revit Arch. I read a post regarding the roads that said -

Just do a sub-region and change the material.

so I went with that for the road. The problems I now have with that are the following -

• It doesn't read well when I move to a later phase. The road and topo appear greyed out. I sense a discussion coming with my Architect and I haven't even printed it yet.
• I can't set the elevation of the road to be slightly above the ground, which it would be in real life. So it just doesn't read well in the 3D views or sections. Again, discussion coming I'm sure. I considered a split region for this since that would give me some added controls for this section, and then raising it up slightly. But aren't I going to have to fake something in the sections there since it will read like ground anyway?

And I'm still not sure how to handle the parking lot and curbs around the parking lot based on my issues with the road as listed above. I was told to just use a short wall for the curbs, but that won't follow the contour of the topo, right? There has to be a better way to do this, right? Hopefully you guys will have some tips there as well. I'm sure all of this is easily solved in Revil Civil, but I don't have that so I'm looking for a way to work with what I have.

[nancy.mcclure]

Tim,
Don't beat yourself up, the site tools in Revit (aside from being able to quickly create a toposurface, and for cut/fill to track) leave a LOT to be desired.

Subregions for roads is a typical approach, although it doesn't create the elevation offset desired in 3D views. It's a site feature rarely being adjusted (unless you're in a masterplan situation) so it's not worth the time investment. If you ARE responsible for road design, use the floor method as well, and add slope elements to roughly approximate adjustments to surrounding grade. Use a SLAB EDGE with a profile of your 6" conc curb to track around the sides of the road/floor.

Topo/Pad:
When you create a Graded Region, the system creates the duplicated toposurface and deletes it IN THE SAME PHASE. I like to select it and move it to the Existing phase, so I DON'T see them both in my New Construction views. Check your view's Phase Filter to choose to see the All, or just what's demo'd + New.

Create (E) Pads in (E) phased views, and they will be depressions in NC. Create pads in NC if they are in your current scope of work.

Hope that helps.