Grading Optimization: Making Choices that Benefit Automatic Grading

RUSS NICLOY: Welcome, everyone. And thank you for joining us. This is the Grading Optimization session, making choices that benefit automatic grading. My name is Russ Nicloy. I am a civil solution specialist with Mesa Technologies. I've been there about five years.

Overall, my career is about 30 years in production as well as a significant amount of time with a reseller. Because of those things in my career, I've been able to work with all aspects of the civil industry. And that includes working with the site design groups that Grading Optimization is going to be the most important to for that group specifically.

A short agenda about what we're going to look at today. First of all, I'm going to do a short overview of what Grading Optimization is to make sure that we're all on the same page and understanding what to expect out of the tool. And then we will be looking at the visualization tools to supervise the progress. That way you can kind of watch how things are developing as you're using it and understand what you're looking at.

Then we are going to look at Zones, Lines, and Points. These are objects that are used by grading optimization to do the optimization work under the hood. Then we will look at how to encourage drainage. And you see encourages in quotes there. This is where you put your thumb on the scale and kind of adjust things so that things are flowing in the right direction from your grading. And then finally, we will look at balancing volumes and other objectives. These are a little bit stricter rules about what your intent is so the Grading Optimization is working in that direction as well.

With that, let's take a look at a short introduction of Grading Optimization. This tool is for optimizing. It's not just a clever name. It is actually what it's doing. It's going to make the best out of the parameters that you give it. And you as the user will be providing an envelope of parameters for it to work with.

Basically, Grading Optimization is like a very large room full of engineers and you're giving each of them the task of giving you their best grading. Now Grading Optimization does one better there because it does that first of all very quickly. But then it also looks through all of the results and finds the best one for you. Otherwise you'd have to sort through them and find that one and go with it from there.

The other thing is that-- I mean it does give you that optimal result from the options but you can decide at any time which one is the one that you prefer as well. So you can move from there.

Some suggestions for use on this because Grading Optimization is not actually a one size fits all kind of tool-- it is not for the overconstrained projects. A lot of projects are so tightly constrained that it basically tells you what kind of grading has to happen and where rather than being open enough so that you can make choices through it. And so those are the types of projects that Grading Optimization really doesn't shine. Grading Optimization shines when it's got room to run and room to work with, maybe not a lot of room but enough room that there are some options that it can find for you.

I am going to suggest that you limit your limits. This is the parameters that you give it. If you need something to be 3% but it's acceptable to be up at 5%, I recommend giving it as much room to run as you possibly can. A lot of times, the 3% will be just fine and you will hit the numbers that you want, but there might be little areas of local need that need a little bit extra room and that will allow it to run without errors and without a problem.

Also do grading in phases. Now this is something that was told to me very early on and really has changed the way that I operate inside of Grading Optimization all the time, quite frankly. And that is you don't have to do the entire project all at once.

You can do the larger area first and then start to focus in on more localized areas. That way the overall site is getting what it needs but then the localized area is getting a little bit more detail. Even running grading optimization several times over the course of a site is faster than all of the grading that you would have to do in the manual version of grading.

In terms of phasing, you do want to change the grading limits because we'll do a grading limits on the outside edge of the project so the rest of our surface isn't touched but then when you go to the more localized areas, you want to move that grading limits in there so it focuses on that and leaves the outer area alone. So that's just something that kind of works well with the phasing idea.

Also you can set preferences for speed versus quality. This includes things like is the mesh being finished off, are you refining the surface, how many iterations or how many options are you going to run through in the optimization process. If you're early enough in the project and you just want to see is this project something that we should pursue, are there going to be any surprises in it, I'll run it for speed and turn some of the quality options down.

Later on in the project when you want something a little bit more refined, a little bit more finished, maybe turn those back up. It'll take a little bit longer but you will get a more finished result out of the optimizer. Also, before accepting results, make sure that you don't have to adjust and try again. There are points where you could stop while it's running if you see things are going in the wrong direction or, at the end, if you just don't like what's going on or you realize, oh, I need to make this adjustment over here, make the adjustment and rerun the optimizer. Again, it's faster just by rerunning it than it is if you are trying to make the manual changes on your own.

So with that, let's take a look at the visualization tools that are going to supervise the progress of the optimizer. In here there will be a toolbar at the top of the optimizer screen. I've broken it down into little areas here. The violation or results area will show color-coded triangles where they might not be meeting the parameters that you've given it.

Now as the optimizer is running, you'll see those flashing back and forth as they're trying different options. And hopefully, those go away but you can watch for problems. Also, you can switch that area over to Cut Fill and you can see the cut and fill heatmap of your surface as it's developing as well. If you turn that area off, then you can go over to the theme area.

This is where you're going to color code things like elevations or slopes or even face directions. That way you can get a better understanding of what's going on to your surface there. Now the theme goes along with the contours and triangles right next to it. You can see my screenshot there. I've got the elevation theme and contours turned on. But there might be a time when you need to turn on triangles for some nitty gritty little area that you're trying to figure out what's wrong. And so you can switch between contours and triangles at that point.

There is an area called hydrology here. Now this is very similar to the slope arrows in the Civil 3D surface analysis, one arrow per surface triangle. And I found that very useful for figuring out where these surface faces are pointing and where the drainage is going to be. And you can find problems earlier on by taking a look at that.

Now that area does not engage unless you're using one of the parameters that we will be discussing called drain lines. But I'll show you that when we get to that point. But that area really doesn't do much unless you have drain lines involved in your grading. Next to that is settings. That's where you control the contour interval as well as advanced settings like ranges or colors for the theme analysis that you can have assigned to the surface.

Finally, there's the vertical exaggeration slider. Now I put a note on that because it just looks like a bar on the side there but it's a slider. You can slide that up and down. In the screenshot there, I'm about halfway up. But what that's doing is while contours provide a great story as to what's going on with your surface, the vertical exaggeration will give you a little bit of a nitty gritty look at what's going on with different areas, maybe areas that are between contours or help explain what's going on with the contour. You can see the edges a little bit better and figure out where things might not be working as well with that on.

Now with that understood, let's take a look at zones, lines, and points. As I said, these are the objects, you're going to use to create your grading in the optimizer. There's things like the zones are going to be areas of grading, larger areas that you're going to be working in. These are generally going to be closed shapes.

What's nice is you can use just a regular old polyline to do them. Nothing special about the object as long as they're closed and then you assign a zone to it. You can do quite a bit in a zone with different parameters for the grading. Lines are going to be linear areas of grading, usually open shape although you could close them I suppose in some situations, but generally open. They're going to feel like break lines as you create them. They're not break lines per se.

In fact, the drain lines that I've talked about already are line objects in there. Also retaining wall. I'm going to put in a retaining wall. And again, it'll feel like a break line but it will then grade off of that as if there's height to that wall and set that up for you so lines are an important addition to this. Then also there's points.

These are locations of specific or bounded elevations. You can go in and say, well, I have a drainage structure at this particular elevation at this location. And then the grading will keep that in mind as it's moving around it. You could also say I want a low point or a bounded elevation, which is going to give you a low elevation between elevation points that you provided, that envelope that you provided.

So with that, let's take a look at Civil 3D. And in here, I've got a very, very small project, just something, a good demonstration of the tools here. I'm going to highlight these three lines that I have here, closed shapes, to show you that they are polylines and the elevation is at 0. There's nothing special about them. I'm going to let Grading Optimization do the elevation work there but I just need those closed off. I am going to go to the Analyze tab, Grading Objects.

And in here, the Grading Objects browser, when we create objects or assign zones and so forth, they'll be listed here. We'll be able to get in and change parameters if we need to. This list over here is the list of objects that we can use. I'm going to use the grading limit first. That's going to be the extents of the grading for this area.

What I found is naming them is very important, especially for later on in the project. I'm going to use custom slope constraints in here. I am going to go with a minimum grade of 0 but a maximum slope-- I actually like 33% but I'm going to open up that envelope some and let it go to 50 if it needs to. I've got kind of a big hill here and want to make sure that I've got enough room for the grading to work nicely.

So with that, I'm going to go into zone. Now a zone is a zone. It is kind of a more miscellaneous type zone that you can do quite a bit with in here. I'm going to name this pad one like it's one of several pads I'm working on. I'm going to go to the Customize Slope Constraints. And here the minimum drain slope I'm going to set to 1 and the maximum slope I'd like it to be about 3% but I'm actually going to set that to 5%, again opening that up as much as I dare to let Optimizer run through there.

I'm going to close out that one and then I'm going to set the building pad which is another zone. It's a more direct zone. It's about building footprints directly. In here I can set an elevation. So if you've been given a footprint elevation here, you can give that elevation directly here or I can ask it to optimize between a minimum and maximum elevation.

In my case, I'm going to go a step further than that and turn off elevation altogether so that building footprint will be optimized with the rest of the grading that's going on in this lot. I am going to level the grading with the pad. The depth of material is just how much concrete or whatever my material is. I'm going to zero that out for today. I will add that in later in a later phase perhaps.

The drain away, I'm going to turn that off. If you've used Grading Optimization in the past, Drain Away is a new feature here which will allow the grading to always run away from the building. Now if I'm in an early enough phase that I don't want that used-- I will be using that later and you'll see me turn that on at a later time because the results are great when you use that. So I'm going to leave that and now I'm going to go to Optimize with those three items included in here.

I'm going to orbit around just a little bit so we get a better look at this as it's running. On the left hand side are all of the objects that I've assigned in here. Here's the building pad and so forth. I can click on them and get to the parameters if I need to tweak them at all.

Over here is the visualization bar. When it starts out, it'll start off in the violations but then I can turn that off and go to theming or something else if I need to. I am going to use the exaggeration here to exaggerate that. It helps my eye understand what's going on even with the contours there. I find that helpful.

I'm going to optimize this and then you can see there's only a couple of errors. This area is really coming in nicely here. I'm going to turn that off so I can look at the theme. It's actually still running here. In fact, the bar down here is indicating it's running.

But I can go in and say, well, instead of a color scale, I want to see a gray scale of the elevations or the slopes. I can see, well, there's quite a bit of slope here in this area right here. I could go to Aspect. There is a key down here that indicates what direction each of these faces is facing over there. And as I said earlier, I could also change to the triangles if I find that helpful in a situation. And again, I can't use the hydrology just yet but I will be using that soon.

Now I've talked long enough that the optimizer has run through all of what it needs there. And I'm a little concerned with the slope in between here from the grading extents down to the pad. And I think we need to put in a retaining wall in that area. So again, instead of accepting those results I'm just going to close the optimizer and then draw in a polyline along the south and western edge here.

And then I'm going to come up here into retaining wall and select on that line. Now the direction that I drew it is important. You'll see that there is a shadow there indicating the top of the wall. If I drew this in the wrong direction, I can simply come over here to reverse the retaining wall and that shadow goes the other direction.

So you can always tell which direction that is. I did actually draw it in the right direction there. I'm going to go with a minimum height of 1 foot. The maximum height I'm about, what, nine or so feet here. 10 feet is probably plenty but I'm actually going to be a little bit ridiculous and give it way more room to run, 15. I don't expect it to go to 11 let alone 15. But I'm kind of getting out of the optimizer's way and letting it figure out what the best option is going to be here.

So with that set, I will now optimize again and then in here we're going to move it around so I can see that better. And I will exaggerate that a bit and then I'll click Run. And now the wall is here but now that surface over here is much flatter. And it's much closer to what I'm hoping for, what I'm expecting here.

We've got a bit of a steep incline over here. And I'm probably hitting two to one over here on that slope but I can see how that's going and if I like it. In fact, it's not done. I could stop it at this point. In fact, I think I will and say, yep, that's done as far as I'm concerned. I'm close enough there to what I need that I can progress with that.

So with that, however, I am going to close that out so that we can talk about other aspects of Grading Optimization. And that is going to be the encouraging drainage. You see that I've got the grading as I want it but now I want it to slope in certain ways so that water is draining appropriately off of this. Lines that encourage drainage start with that drain line. It's one of my favorites.

In my screenshot there, I've actually got two drain lines there outside the extents. What those do is those attract the slope of the triangles so that they encourage that drainage. That's where the term is coming from here. I've got two of them there so triangles are going towards the one that they're closest to so I'm getting a nice drainage off of two different sides of our site there.

Aligned edges are used when you need a consistent slope away from a line. It kind of creates a break line type idea through there and then translates the triangles away from that line. Bend lines are there for surface triangles that you need to relax the parameters. Autodesk says relax and I'll say ignore. It basically will go into an area that you need to make a tweak to but you don't want to mess up what else that's gone on so you can use a bend line to relax or throttle back those parameters in a localized area.

The points that encourage-- oh, I'm sorry. Offset points. And again, offset points seem like they should be in the points area but really it is a line tool. You create a line of a certain distance and then tell it what the difference of elevation should be. Then over that distance, it figures out where the surface should end up for that grading. So you are identifying points but it's using a line to do that work. And so that's why it's in the line category there.

Points that encourage drainage-- low points. You could put in a point that's specific to an elevation like a drainage rim location or a low point. So as the grading is going, it's always keeping that point lower and making sure the drainage is always going to that location no matter what else is going on. A bounded point does that same idea only it keeps it between an envelope of elevations there.

So with that, let me switch back to civil 3D so I can throw some of those in here. First of all, I am going to create polylines for my drain line. Now I'm going to create a drain line right here. And what's going to happen is the triangles of this area here, because I have a minimum drain slope, my outside the extents here had a zero in there so they won't be involved but the minimum drain slope is at 1% so all of these triangles will be faced towards this line at at least 1% and maybe more, probably more in some cases. Now on the east edge of that line, those triangles are also pointed back towards that line. And then any triangle that touches the line goes from the first point to the low point-- the second point, which is the low point.

So basically, I've got a ditch about to be created here and that's not actually what I want. What I want is to move this outside of our extents. Now the entire area here will be pointed to that line, to that drain line. And depending on where I have this situated, a triangle back here is going to point towards the line but it'll make it a little bit more north and east. If you want it due east, you can move this line back and adjust it so that those are more in line. I actually do want it a little bit more up in front here. And I'm going to draw a second polyline like that screenshot you saw earlier there. I want to encourage the triangle faces to go in two different directions.

I'm going to grab the drain line tool. This is one of those weird areas where I can grab as many drain lines as I deem necessary because the only setting is what the name is and what the break line setting is. I'm going to leave both of those on. Then I'm going to draw in another polyline here. I'm going to attach this to the front of the building. I'm actually going to draw it outside of the extents there.

Now you wouldn't normally put it out like that. In fact, this is going to cause a problem later on. But I want to show you in context what it's doing. I'm going to set this as offset points. And then in here I can set an elevation difference or a minimum/maximum elevation difference. So again, it's got some play. I'm actually going to turn it back to fixed and set that to a negative 3 so that over this distance, it will drop at a 3 foot drop there.

And finally, I am going to put in a point. I'm going to use a surface point here on this point right here. And I'm going to select on that point. Let me edit that point so that you can see exactly what it's got there. It put it in at an elevation of 849.25. And I want you to remember that number. 849.25. And then with that, I am going to tell it I want a bounded point there. I'll select on that point object. And in here, 849.25. So it did immediately reflect the elevation that it had been given or that I gave it, whichever. So it's reflecting that number there.

Now I'm going to turn off the fixed elevation and I'm going to go in and put in an 845 for the minimum, so way down, or an 847, at least two feet down, for the maximum there. That way that point has an envelope to stay within depending on what's going on with the rest of the grading here. With those set, I am going to go back to the Analyze tab and optimize. And then in here, you'll see those new objects are now listed in here or displayed in here. And I'm going to exaggerate the surface because this one's going to be a little bit chunkier. I'm going to go to Optimize.

And then in here and this line, you can see that we've got quite a bit of drop here. It's not going all the way outside the extents because the extents is the end of grading but it is reflecting that distance for that three foot drop over there. It's making it quite chunky over here. In fact, it's chunky on both sides here. Another one is this point is staying low enough that it's creating a drain point here from all around.

Now at this point, I look at that like, well, no, that's not acceptable, what I've got here. I've got to make a change or my parameters have to change or something. I'm actually going to go to my Object Browser. And down at the bottom is where the offset and bounded points are listed. And the offset point here, I actually want to deactivate that. So I'm going to click this slider button here to deactivate it. Now it's still there so I could always come back and try it again later. Maybe I make some other changes in it.

OK. Let's see if this is going to work now. But in this case, I'm going to leave that deactivated. In fact, I'm going to turn off the visualization so the line no longer shows up in here, now just kind of a clue to myself that that's no longer active. The bounded point I'm going to do the same. I'm going to deactivate and then turn the visibility off.

Now with those changes, I'm going to reset this back to before that run and then I'm going to optimize again. And now much smoother on the outside here. This is still flat but we've got a little bit of movement there. I'm going to turn on my hydrology and you can see that the arrows are pointed towards those lines. In fact, if I move back here, you can see these arrows are pointed towards the end of this line here. So that is their role there. Now as that's going-- and again, the feasibility is getting towards the bottom here. I like what I'm getting. I can hit Stop at any point here.

There are some other things that I need to do in here before we continue on so I'm going to stop the optimization there and go on to talk about the balanced volumes and other objectives. These are the stricter rules that it's got to follow. In the optimization options, at the bottom is the objective weights. And this is where you can say I want to either bounce the cut and fill, minimize the earthwork, or smooth the surface.

And you can see in my screenshot there, I've got 100% set for the balance cut/fill and zero for the minimize earthwork, which means there's absolutely no consideration for minimizing the earthwork. It's just going to figure out where the cut and fill is going to go. You can have these sliders set to whatever combination that you want but that may increase the time of calculation. But especially in the later phases where you want a more finished result, that might be what you need there.

Something else in the optimization options there are the global constraints. I've chosen to use custom constraints in the areas that I'm using but the global constraints are kind of an overall if you don't use custom. They now include the cut and fill constraint. Now this is also a new function inside of Gradient Optimization. Right now, by default, it's set to none. You can set it to cut only or fill only so that would make decisions in your grading area based on that choice as well.

Also in here is the optimization iterations. The default there is 100,000 but if I'm in the earlier phases, remember that speed versus quality discussion, this is where I can turn that down so I'm not running through as many options here. I'm going to get close enough that I can figure out what's going on but it might not be a finished version of the surface that I'm looking for. So that's the iteration area there.

The Preferences dialog is another area for that speed versus quality. And that's where you can decide whether you're going to refine the surface, what kind of mesh quality. The default is medium but you can throttle that up and down. You can also tell it what kind of maximum triangle size that you want. I have that turned off but you can set that if you've got rather large triangles and you need those broken down for a little bit more detail in your design.

So with that, let me switch back to this area here. Now I am going to reset the grading here. And then I'm going to open up the preferences so that you can look at that. Now I'm not going to change any here but this is where you could get that. It's the lower left hand corner of the screen. But I am actually going to go into the optimization options.

And in here I'm going to change the balance cut/fill all the way down to zero and swap that out for minimize earthworks. Like I said, I could do whatever combination I want. In fact, smooth surface I'm going to leave at 50. It's in the calculation but it's not the important one. It's only partially being used there. I am also going to turn the iterations down to 25,000 so I'm not running as often there. I'll close that off and then I'm going to click Optimize there.

And now as that's running, I'm going to open up the convergence area there. That's this button right here. That gives you the plots of is this feasible. Is it going to-- I'm going to stop this right here so I can show you something. It looks like it's still running but it's not. The iterations down here are on the volumes. And you can see that the net is way high into the cut. We're not balancing cut/fill here. This is reducing the amount of earthwork that's being done.

Now I'm actually going to go into the optimization options and swap that around. And then normally I would reset because I want a good, clean start but I want to optimize that again so you can see the difference there in that list. The net is now at zero or as close to zero as it can get. And you can see the cut and fill is now way different than what it was earlier. I still am getting the smoothness.

In fact, you can see where I started that new option here because the feasibility started over and I got down-- now it never got down to zero but it got to 25,000 and said, OK, here's what we came up with from here. So I'm going to close that out there. Now I like what I've got there, generally. It's still rather flat. I've got some good drainage here. I'm going to update the drawing from this. And it always sets me back to my slide deck when I do that.

There we are. And that opens up this optimization result in Civil 3D. I'm going to go to the feature lines and turn those off. A lot of times I leave that on. They are important tools. But I'm going to go to surface here. And I'm going to name this surface grading phase one. This is that phasing option here. So I'm going to create the surface from this.

And then you will see this now. Actually, I got rid of this line and this point earlier. I'm just going to delete those so that they're not in the way. But you can see the new surfaces here. Now I'm going to take the original existing ground and display that so that we see just that. Now phase number two here is I'm going to go in and make sure that we've got drainage away from the building, especially over here.

We've got some drainage towards that building and I see that is going to be a problem so I'm going to put in a polyline at about where I'm concerned with that drainage being there. And what that's going to do is that's also going to cut off any drainage here and let it roll around the surface as it goes. I'm going to add that as a grading limit.

Now we still have the original grading limit. And we can really only have one active at a time. But I'm going to set that right here. This is going to be the building extents. And I'm going to customize that to be at least a 1%. And the max slope, I'm going to go with 3%. I'm thinking maybe 5% but I'm going to go with 3% here.

Also what I need to do is go into the building footprint and turn on Drain Away. The whole point of having that off was the surface triangles near the building are facing these drain lines. Well, I want those now just draining away and ignoring those drain lines so Drain Away will accomplish that for me.

Now I'm about to make a mistake here. I just want to call this out. I'm not turning off the original extents here so that will cause an issue. I just want to show what that looks like and explain the context of these areas here. I'm going to exaggerate that a bit. And I'm going to run Optimize. And the first thing I notice is I've got grading all the way around here. Now wait a second. That's not what I wanted. I just want it around the building. Why is it running?

Oh yeah. I made that mistake earlier. I'm going to come up to Object Browser, Grading Limits. And just like I did with the other tools, I'm going to go to Grading Extents and just deactivate it. Now I'm not getting rid of it. It's still part of the overall site but I just want to turn it off so it's not being used there. Another one that I have to do is the retaining wall.

I'm going to turn that one off as well because that's outside the new grading extents. That would error out. Now I don't think it would stop anything but it would pop up an error. I'm just going to turn it off because I know what's coming. So with that, I am going to reset and then run the optimize again. And now you can see much better it's only changing in this area here, in fact, mostly here where I was concerned with it in the first place.

And just the amount of time I talked there, we're already at the 25,000 options there. I like what I've got there. It looks decent enough that I'm going to go with it. By the way, it did pop up some errors in here indicating some things were outside my extents and that's fine. I knew that was coming. I'm going to dismiss those warnings there and update my drawing.

Now in here again, I'm going to turn off the feature lines but I'm going to go to surface. Notice that it's allowing me to update my first surface or the surface that I picked to run against, that grading one. In this case, I am going to choose to do a second surface here so I've got kind of a bookmark as to what happened earlier and what's happening now. I'm going to change the style here to the design so we can take a look at that.

And now there is that new surface in here. In fact, with that I'm going to grab the water drop analysis tool to show that water is running through here. And if I'm inside near the building, it's running away from that. Now these are actually running from here down and would run off the edge over here and so forth. But that tells me that that grading is doing what I want. Maybe with a couple extra tweaks, I'd have exactly what I need. But that is where I'm at for the grading.

So with that, I do want to leave you with some takeaways from the session. First of all, use the visualization tools to supervise progress. You do not need to let the grading run itself out before you make changes or fix things that you see are going wrong. In fact, you don't need to accept the end result at all. You can always just stop and redo something at any time.

Grade in phases. I can't tell you how important that's been over the last couple of years in the way that I interact with Grading Optimization. It's faster to do that than it is to try and get everything to work across an entire site. A lot of your sites are so large that would be very difficult in the first place. So keep that in mind.

Drainage changes depend on where you place the encouragement. Notice that drain line had. I made it shorter and longer. That actually changed the way that that encouragement went. Also changing the parameters obviously will as well.

Remember to set the objectives, speed versus your quality, and depending on where you are in your project there. With that, I do want to thank everyone for their time and enjoy the rest of Autodesk University.