Tips and Tricks of Revit to Autodesk CFD: A-Z Tools for an Optimum Transition

GILBERTO FERNANDEZ: OK, how are you feeling this morning? Well, last day, you know? AU after the party. I hope you enjoyed it yesterday. So first of all, thanks for attending this session on Tips and Tricks of Revit to Autodesk CFD. So basically, this is going to be a description of a set of tools for an optimum transition between your Revit model and CFD.

So about me, a little bit to present myself. My name is Gilberto Fernandez and I work in the Premium Support Services in Autodesk. Basically, we are the people responsible, technically, about the technical issues for our premium customers. My experience is mainly in aeronautical and mechanical engineering. I've been working in the field of stimulation and CFD for around 15 years, mainly within my team, I am one of the big advocates of applying simulation to the AEC industry, OK?

To summarize a little bit the things that we're going to be doing today, just mentioned that taking the Revit models and the architectural models into simulation has become a good topic as companies, within their BIM efforts, want to include some simulation stuff, some fluid flow, in terms of measuring things like the energy savings and stuff like that within their BIM workflow.

So basically, my intention is the class to be taken as a little bit of a reference or documentation for getting, somehow, the tools for you guys to take the models over to CFD. First thing, I wanted to ask more or less, hands up, the ones that use Revit. I guess most of you do use Revit, right? Yeah? Any experience in simulation, CFD, in particular? Yeah, a few of you. Good stuff.

So the learning objectives for this session are going to be, first, to see how the Revit models are launched and interpreted in CFD. Then to recognize the tools that we have available to prepare these models, then apply those changes so our model is ready for simulation. And then, another objective will be to-- at least personally for me-- so you can keep the class materials as documentation for future Revit projects.

So in the agenda for today, there's quite a few items as you can see. I will try to go through them real quickly. First, I'm going to give you a little bit of introduction-- a description of what CFD is, what we do with the CAD model, what that Revit model is. Then I will tell you a little bit about how you launch the Revit models to CFD. Different ways of doing that, different ways of modeling the internal flow.

Then, for me, the two most important parts in here to actually change-- shape a little bit the mindset from the AEC industry into simulation. This will be all around how CFD interprets the Revit model, and what tools we have within Revit to prepare it.

Then finally, I will tell you a little bit what working with CFD is, and how to do some stuff in there so you can see what can be achieved in there from your original Revit model. Then you can achieve results, take decisions, and so on. I will give you also some additional information, additional resources there. And then hopefully, we'll have some time-- around 10 minutes or so-- to go through questions and answers if you have any questions.

So first, as an introduction, let's describe what CFD is. You can see there the CFD interface. Basically, CFD is a simulation software. We shouldn't be losing the focus on that. As one of my colleagues said yesterday in one of the classes, some old statisticians said all models are wrong, but some are useful. Don't forget that we're talking about modeling here. We're talking about numerical analysis, so it's a numerical approach to try and predict the fluid flow and the heat transfer. So we're going to be trying to predict the behavior and the performance of our fluid flowing around and of the heat transfer. And the key point is we will need a volume of control and we will need a mesh. We'll see about this later.

And in reality, CFD and our CFD in Autodesk is meant to be applicable and used all throughout the design process. So there's different phases that you can apply that. First, the concept phase, where you're trying to think about what you can do. Then the development phase, where you're actually developing something. You're manufacturing your things. And finally, you can also use your results for marketing phase. So for spreading the word of what you've done, and how good your design is.

In terms of CFD, we do work with a model. So we need a 3D mesh, we need a volume of control. Sometimes, we can say that the generation of this volume of control can be an issue there. We'll talk about this a little bit later. Just one thing to remark in here, that the optimization of our model. Normally, we get production models. We get really big, complex architectural models. And they have too much detail.

So the key point in here will be to drop detail, but at the same time, keep the significance of it. So this can be a little challenging. And for this, we need to know, what are the details? What are the parts that are going to be potentially problematic? So for doing model check-in, we do have something which is called the Model Assessment Toolkit. This form-- it's kind of a part of the process of launching the model from Revit to CFD. It is basically a tool where we can go around our model and we can identify and locate potential problems. It checks for things like slivers. It checks for things like interferences, gaps that we may have in our model, and quantifies them.

It is important to notice that the Model Assessment Toolkit identifies and locates potential problems, but it does not fix them. It's just for checking them. In terms of modeling the internal flow region that we will be needing, there's different ways of creating this flow region. First one-- obvious one-- we can generate things in AutoCAD and in CAD, actually. Well, AutoCAD is one of the possibilities in your CAD. In this case, in Revit.

It is good because it gives you good control over what you're doing. I'm guessing that all of you guys are-- you have your good skills in Revit, so you can draw the things around. But in some CAD systems, the generation of this volume just filling these parts can be a little bit challenging, really, with the tools that we have in something like Revit.

So second method we can apply is to have a void airtight. By this, I mean-- and you can see in the pictures, we can generate little parts within Revit that kind of cap our model. So they, in fact, generate that void. So in a case like this little valve, we're generating a couple of parts on the side, so we leave the internal as void, yeah? It will be the same in a building if we actually close completely one of the doors. So the internal will be void. And then the good thing is CFD will void fill that part.

Third method is to create this region within the CFD once we take our model over CFD. The good part is we're not using the CAD at all. Bad part in there is it is a little bit limited because we only can generate feel like planar surfaces in CFD to close my model up. So it will not be that-- it will not be that easy. So I would say that for Revit, the preferred method will be the second one, will be to generate these little extra parts to close our volume, so then CFD can void fill.

In terms of a Revit model, this possibly will not be any surprise for you guys. Revit is not really that much-- is not really only a CAD system, but a design and documentation platform that supports the designs, drawings, schedules, and everything for BIM. It will be like the central point for our BIM efforts, OK? And it collects the information for all the representations of my project.

Revit, as you know, works with projects, and then within these projects, it works with elements, also called families. And we have three main branches in the three different types. We have model elements, which are the standard ones. We have the doors, the windows. Then you have the structural parts, the piping. Then we have the datum elements, which in there, we can see the grids and stuff. Then we have the view-specific elements there, like dimensions and things. So the behavior of these elements will depend a lot on the context in which they are within Revit.

So let's see how we take the model from Revit to CFD. This, actually-- what we call Launcher-- this launcher is located within the add-ins. So it will be around there. You can see on the top, the add-ins. So this launcher gets installed when you install CFD. It does recognize that you have Revit, so it installs this thing.

The two options that you have are to use the Model Assessment Toolkit or to launch the model directly. With the Model Assessment Toolkit, as I said before, you can check around and see the parts that can be potentially problematic. And then, CFD generates this void fill for you.

Then, when we get the model over, CFD works with design studies. It works with a little bit of structure. There is some hierarchy there in the structure. So it works with something that's called a design study. This, I always say, is the main container of our study. So it's more than a file. It's kind of a framework structure.

The design study can contain multiple designs and multiple scenarios. So within a study, what we want to do is we want to contain everything that we do, or everything that we do with that study. So in there, we have designs, and every unique geometrical variation will be actually considered a design. So we can have multiple of them, and every design can contain multiple scenarios. The scenarios are basically the set-up for individual analysis.

What changes from scenario to scenario? Basically, what changes are the operating conditions. So we can change the materials, we can change boundary conditions. We can change things like that from scenario to scenario. So you can see that, in CFD, you work within a structure with different geometries, and also different operating conditions. We'll see later how working with this type of structure will help us a lot in taking the actual decisions based on our results.

Then, finally, the launching can also be done. Apart from getting this launcher, this little button that we saw some slides back, there's the option also, from Revit, to export a file. One of the standard operations and exports from Revit is a SAT file-- SS file, which is a neutral sort of file. It is not bad. The problem that we have with this kind of export is that we will be losing a little bit the associativity, name-wise. Because SAT files, when they are saved in there, it doesn't recognize your elements. It recognizes just part 1, part 2, part 3-- component 1, component 2, component 3, something like that. So you actually lose your naming in there.

With a SAT file, there's two options. We can get the SAT file. That file can be read directly in CFD or you have another option, which will be getting your SAT file and get through some sort of a middle CAD Tool. And we do have two CAD tools that come with CFD that are called SimStudio and also Fusion 360. This comes with CFD. So you can load up your model in there and then launch it from there.

If we're talking about this SAT file, it will be better to go the second way-- to load that up in SimStudio or Fusion 360. Because, well, we've lost already our names around there. But we can take that base model and we can do changes in there. And we will keep some sort of associativity between the Fusion or SimStudio and the CFD. So between those, it will be the best option. Possibly the very best one is to launch from Revit, as your things are going to be recognized. I mean, names and so on.

Then we're going to see how CFD interprets that Revit model. I think this is the most important part because when you have your model in there, you wonder, OK, how are my parts, families-- everything that I have behind-- how is that going to be interpreted within CFD? First, we need to say that CFD interprets only the active view and only the visible elements. This, at least to me, is a piece of good news, really. Because OK, it allows you to play around with the elements, get some things on my view, get some things off my view, hide elements, and these are not going to be taken over.

It works only with what I see visible within Revit, but if I am, in fact, editing one of my families, I can see quite a few things, like annotations, references, constraints, dimensions. Those are not going to be taken into account. It's just getting my elements, the elements only that I see. Then, in terms of families and the instances, the families will be interpreted as separate parts. Then, if a family contains different bodies, different subparts-- yeah, you may have a family, maybe a door with a lot of detail in there-- those ones will be also interpreted as separate volumes within CFD.

The families and also their instances in CFD, we need to notice that they're going to be taking us completely detached and unlinked in there. So the link that we had in Revit, where if we changed one instance of the family, the rest can be parametric in there and they can adapt. In here, they're going to be treated exactly as separate objects.

In terms of the naming, the name that CFD will get from the families in Revit is going to be based on the family type and then the family name. And then, if you have instance name, it will be taken as well. The thing is, in that interpretation, CFD will be taking any subparts in there with the same name-- same name as in your family. So you have duplicated names. Only in CFD, for separate volumes, you're going to have separate tag IDs. Same thing happens, actually, with the instances.

In terms of interferences, this can happen, I guess, quite a bit. For instance, you model lighting features there, like in this case, and when we draw the ceiling, these things go through the ceiling, yeah? In CFD, this is allowed. This is understood. Doesn't have to be a problem at first. So nothing to be too worried about. Only notice the way that CFD will be interpreting these interferences.

As you can see in the picture on the right, CFD will interpret the two families separated. So the part of family one that does not intersect, the part of family two that does not intersect, and then the interference as a separate part, or multiple separate parts if you have multiple intersections. So it will be generating those parts. The naming that it's going to be using is going to be Family Name 1. As you can see there, family type, Family Name 1. And then an underscore, U, and underscore on the other one. So this is the convention that it uses for names when you have this interference.

Again, I said it doesn't have to be a big problem, but it may, and I'll get into some funny interpretations in there. So within the interpretation, there can be errors or there can be misinterpretations in there-- special ways of interpreting our model, yeah? So this is why I call it lost in translation. You can see our friend Bill Murray there in the Lost in Translation movie with a frustrated face in there.

So first one is an error that we can get, and that is a general associativity error. If you've tried getting Revit models into CFD, this may have happened to you. The thing is, it is more of a warning rather than an error, and it tells you that the Revit API is experiencing some difficulties with the names. So the names are going to be lost in there. You can see that every part is considered-- you can see that, on the right-hand side, every part is going to be considered as CAD volume. And this is what CFD calls an unknown part.

So in reality, you're losing your naming in there. You cannot really identify properly your parts in CFD. It makes it a little bit hard. It's not the end of the world, but it can be a little bit of a nuisance to you. The potential causes for this are sometimes, when you do elements that are built in within the project, instead of separate families, this may happen. And then, from my experience, the main cause of this problem is to have important drawings, or legacy drawings, within the Revit model. Most possibly, it's something that sounds familiar to you. Sometimes, you get the Revit model and there's a lot of DWGs being imported in there, being linked in there from past stuff. Maybe you don't need them, but they're just in there.

So a good solution for this will be getting your actively view elements. You copy them, and if you open a new blank project and paste those elements only, it's very likely that this thing will not happen. Because the whole thing that the API struggles with is this legacy imported drawings in the background.

Then there's also, currently-- and I'm saying currently because we are working on that, but I thought I may mention this-- there's currently a limitation within the length of the names that we have in Revit. So it is currently limited to 63 characters. If you have more than that, when you get the model over, you run the risk of CFD crashing on you. So we need to be a little bit careful. This actually links with the fact that, with the interferences, as I mentioned before, we have this naming convention where you get Family 1 full name, and then U and Family 2 full name.

So I know that, in some architectural models, some of the family names can be pretty long because you describe. You can say Compounded Ceiling Made of Concrete Number 2. So you have quite a few elements in there. So if you have an interference, that will add a little bit more length, so you may run into this risk, OK? This is something to be taken into account in there, yeah? So just a tip, really, for the case where you're taking your model over and you suddenly see that it's not working or crashing.

In the interferences, too, as I mentioned before, it doesn't have to be a real issue. In particular, in those cases, for instance, where you have a full lighting feature going through a ceiling, it's fine because that interference is kind of a fake element, which is not a big deal. But if you have very tiny little parts-- very small interference, very small overlaps-- then potentially, in CFD, you're going to have very small parts. And these very small parts can affect a bit how we generate our CFD model, yeah? Those of you that have dealt with CFD know what I'm talking about. Then when you generate the mesh, then the elements are going to be really too small, so unnecessary small, probably.

Then in terms of interpretation, we get to other types of objects. In Revit, we do have MEP, fabrication objects. We have linked parts. We have a lot of things. So those are recognized OK. MEP, fabrication objects, they're recognized fine. Same as the standard architectural elements like doors, windows, and so on.

Then, in terms of linked parts and models, these are also taken as regular families. As long as they're visible, they're fine, yeah? Even though they're linked and they belong to something else, as long as they're visible, they're going to be taken over again, interpreted exactly the same. Like naming, everything, totally standard.

The only ones that are not fully taken there are pipes and the pipe fittings in there. Those are not considered to go through. To me, this is kind of an as-designed sort of thing. It's not an issue really. Because it is normally something that we want, something that we desire. Normally, we don't want to measure-- we don't want to take over the pipes and the pipe fittings. Because they normally go inside the walls and normally, the only thing that they would be doing, in particularly, if you're doing fluid flow, will be to add unnecessary detail. They're not going to be that significant, yeah?

But if they are significant, it will be recommendable to actually change the family type and make it just a simple duct or something within Revit, OK? Then there's also some other "lost in translation" issuing here, which is some complex parts, you may see that you take your element in Revit and, even though you can see us in the right-hand side-- you can see different names-- there are several parts that are still interpreted as CAD volume, meaning a little bit of unknown in there. And I went around and around wondering, what is wrong with these parts? What is wrong with this compared to the next little part there?

I found out that, particularly in that case studies, part of a hinge of a door, that error happens when you have some features, like in this one, there's a sweep in there in Revit. And when you have features and when you actually edit that sketch, that sketch is made out of multiple closed sketches. If you have a single one, it works OK. If you have multiple within the same sketch, and then you apply the sweep to the whole thing, then that confuses the CFD a little bit. But easy stuff. You can actually get to edit the profile, and then, with your profile, you can actually separate that, yeah? So you can do different sweeps. It's fine. It gets recognized, yeah? Again, this thing about CFD recognizing three or a few number of parts as unknown doesn't need to be a really bad thing, yeah? But in case you want to avoid that, in case you want that to be recognized, then this is what you need to do.

Now, over to the Tools to prepare the Revit models. We can see that in the active view-- as I mentioned in the interpretation, CFD recognizes only-- it works only with the active visible elements. So it is a really good trick in there to go to the View Menu and go to Duplicate. Go to Duplicate the View, and play with it. Then you can zoom, you can select different parts. And that makes it really useful for you without having to disturb your Revit model and your standard views of the Revit model, OK? So Duplicate the View. You can even rename it, and then call that view CFD Export or something. And then, you can play around with it. Just remember, you're going to be playing around with it only on a viewing level. You hide parts in there. The parts are still in your Revit model, but they're not going to be taken over to CFD.

Then, following tool, and one of the key ones, will be the use of section boxes. For this, I wanted to put a video in here, which is not particularly working properly. So I can play that for you here. Oops. It's not-- OK. Let's see if I can-- no. Let me see. I cannot, for some reason. OK, well I'll describe it anyway.

Yep. So the section box, you can see on the left-hand side. So it's basically a tool that limits the shown geometry. So the edges of that box will be cutting edges for your elements. It can be found in the 3D view properties. So you take that in, and the section box, as you can see on the left-hand side, appears around. And you modify the edges, so you'll be cutting your model.

It can also apply to selected elements. So if you select a bunch of elements, then you can create what is called a selection box. Then it applies a section box, but bounded by your selected elements. So this cuts your Revit model out. And then this will be a great tool when you have very, very big models, but you only want to restrict that and run for just a small 3D-- just a small 3D part.

In terms of interference detection and solving, we have the tool in Revit called Interference Check. So it exports the interferences in there. It is placed within the Collaborate tab in Revit. And you can customize the selection. As you can see on the left-hand side, you can customize the selection of the elements to which we apply this. Normally, if you click All, you will just do a global interference check.

So the results are given within Revit. Good thing is it's kind of interactive, so you can click on the actual parts, and they get highlighted in the Revit model. Good stuff to see where we do have the interferences. Then, it can also be exported as an HTML to do further checks there.

So overall, it is a really good tool. Sometimes what happens with interferences, particularly the small ones, is that they're very hard to locate sometimes. I mean, they're not intentional. Sometimes they are unintentional, and it's really key to be able to locate them.

There's another way of interpreting the interference detection. So it is with this Model Assessment Toolkit that I mentioned before. So in between your Revit and the CFD, there's this Model Assessment Toolkit. The main advantage, it does mainly the same thing. I mean, an interference is an interference. It will be checked in Revit. It will be checked in the Model Assessment Toolkit. But advantaging here is it will give you values that you can see there. It'll give you quantifiable values.

So what is this useful for? It would be useful to spot the really potentially dangerous parts, which are the ones where you have a very, very tiny interference. Normally, they actually go, as you can see in there, in ascending order of the actual interference gap. So normally, in a case like this, we have the standard ones. Those are the lighting features going through the ceiling. They all have the standard kind of thickness, yeah?

But you can see there that there's a couple, but they're way, way, way smaller. So those are the ones that can be-- that we can tackle, OK? Good thing, as well, in here, in the Model Assessment Toolkit, is that we have an isolate tick box and a zoom tick box. So it actually goes exactly to the point where you have the interference. So you can act on that. In order to sort these things out, usually, the key point for these interferences-- particularly the small ones-- the key point will be just moving or redrawing your family. Normally, just moving a reference or moving a constraint will do the trick.

So instead of you have maybe two walls in there colliding a little bit with one another, so you modify the constraints or the references. So you get them mating-- like meeting in there instead of interfering. All right? And you can move those ones or you can actually do, like in the case of the ceiling and the lighting features and stuff like that, you can try and do cutouts within your part in Revit-- within the ceiling part in Revit.

We do have, actually, some people, some customers-- and I will mention this, the possibility later on. We do have some customers that have even automated this process, yeah? Cutting out the interferences. Another really key tool in here-- key trick-- will be to simplify the actual families. Normally, the main examples that we can work on in here are the doors and windows, really. Because you have a lot of families, even families being up there on the web being generated by the manufacturers and so on that you may use. And within the families, the feature in there will be really important. We don't really want a lot of detail on our CFD. The presence of the handle on the door or on the window, the special aesthetic, like detailing there on the door, on the window there is not really going to be important for us. So de-featuring will be pretty important.

Key trick, instant one for things like this, you can go, for instance, for the doors, and you have your complex family there. But you always have generic ones. So in reality, for the purpose of the CFD, most of the times, it will be as simple as getting to your family type and then, instead of getting this complex one, for instance, in my model, you'd go there for standard door. What can be the problem in here will be possibly to get the right dimensions for that door. That will even not be massively important in CFD unless you want to do a very detailed thing where the materials come into place. But in most cases, it's not going to be that important. But you can go to a generic one, and then it's going to be really easy for us to change the dimensions. Because some of them appear in the actual properties of your door. So it'll be really simple to go there and generate something very, very simple.

The good thing is when we change that family, then all over our model, this is going to get changed, yeah? Because Revit works in this parametric way. For families like that, we can even go to in the background when you, for instance, receive a family from a manufacturer, you can even get the background SAT file and stuff that is behind it, and then redraw. You can always redraw stuff in there and draw a simple door around, or a simple window. This links also with the next little trick in there, which is playing with the detail levels.

Then, I'm sure, if you're familiar with Revit, you know about the detail levels. So Level of Detail, as it was called before 2019. Now it's called Detail Levels. Same thing. So there are view scales in there. So you have coarse, medium, and fine. Sometimes, the default families, they already come with a kind of a chorus version. But within the family, we can easily do the following. You get the complicated stuff. We do a lot-- we do that a lot, for instance, for windows. You can get the current geometry. You can draw, on top, your simple, normal rectangular window. And you can include that in the course level of detail. And you can still keep all your detail, but in a different detail level. So it's a really good way of instantly de-featuring your stuff to get it ready for doing our simulation.

Another one of the big challenges in here-- this is the part where we need to adjust and set a little bit of a different mindset here-- will be to close the gaps. So the key trick will be to try and close that clearance, for instance, below the door. Why do we need that? We need that so we can have the internal void so it can be void filled and we can work with it, OK?

Then, this can easily be done by editing and changing the constraints or changing the dimensions. Yeah, it helps because all the families, they have these parameters. Notice in here that, sometimes, it's not about clearing that, but just defining that little gap. Because in our simulation, we may need that little part to feature in there. Because in our simulation, we may need the air or the fluid to go through that clearance. So with that sketch, we can generate that part, and that way, we can kind of close it, yeah, so we generate an extra part.

Then, in terms of closing the top parts, like ceilings and stuff like that, on that, we have a little bit more freedom on it because what we're really concerned about is only the internals. It's only the internal part of our-- it's only that the internal part, the air, inside. So we have a little bit more freedom. So we can do the ceiling a little bit thicker, bigger. It doesn't really matter that much.

Then, I must mention also that we do have Dynamo, which is a general programming interface for customizing stuff. It's an open source code, free to download, and basically, you program things within Revit. Really good for doing your own automation once you know these tricks. I actually included a sample script in there in the handout for you to check there. It's a very simple one. It gives us warnings to try and avoid that problem with the length of the names that I mentioned before, OK?

So let's briefly, finally, describe a little bit how CFD goes, how to set it up. Once we get the model in CFD, we get a set of tasks in there, so materials, boundary conditions, initial conditions, so on. And for every task, there is a context in there where we do editing, selecting, and so on. So there are four different stages within the setup of a model in CFD. So you have materials. We need to define where are my materials, where are the solids, what are the flows and stuff. Then we put the boundary conditions. So that's the inputs to our model. That's what we know about the model.

Then we do meshing, which is basically breaking our model into small pieces so we can apply the equations. It's a really important part of our model. And then we do the running parameters, the operating conditions. So we define, if we want to run only fluid flow, heat transfer. If we want to run steady state, transcend, et cetera.

So then, we can see in here, results in CFD. So we visualize this and we actually get what we didn't know. So we put what we know, and we learn what we didn't know about the model. There's also one video in here that, if you see the actual hand-out, there's going to be links for that. So the good thing about the results is you can interrogate the model quite a lot. You can get the variables of velocity, pressure, and density, temperature all over your model. You can actually even put streamlines and get how things move around, how the fluid moves around, which is an important feature in the AEC industry. So it gives you a whole range of tools to view your models.

Once you view your models, then it's time to take decisions. This links back to what we were saying before about having multiple designs and multiple scenarios. So I'm going to put you a couple of examples real quick. So in this case, we had a result from-- this is a lighting feature, really. That is a PCB board with the little rectangles in there. The little cubes are little LEDs. And then you have a heat sink in there so it dissipates the heat.

So first, we run-- this is a real case, by the way-- we run three different scenarios. And what we changed in there was the actual materials. So we used different materials for the PCB metal core 1, standard PCB. And we measure-- and the good thing is we have an environment called the Decision Center so you can compare your results like to like. So side by side in there, you can see different temperatures. Visually, you can see that one is colder than the other. So we take the first decision in there.

But then, we also change the geometry. And what we change in the geometry is the way the heat is dissipated. So you have a different heat sink there. So then, even a different one changing there how many slots in there we have for the heat sink. So you keep on taking your decisions, adapting your model, and generate a full design study where you can see trends and make your design optimum.

Then, finally, there's a real example in here about an operating room. This is also a real example with one of our customers. So they want to improve the ventilation. 1.2 million people die for secondary infections in operating rooms, so the ventilation of a clean room is really crucially important. So you can see, this is part of our result. You can see it streamlines in there. You can see the lines of the flow going all around, all over.

So this is about redesigning the ventilation system. So you do changes in there. You change the actual place where the ventilation systems are, and you change the flow as well. So you eventually get something like this. So you do a design change, and this is the actual way that the particles of the ventilation go through. So this clearly pushes all the air around the room so you can see that nothing now will recirculate to the patient, OK? So this is the powerful stuff of getting the results and taking decisions based on them.

So as additional resources, we have online help for Revit, CFD. In particular, I want to stress to CFD one is really, really good. You have a lot of training materials in there. You have a lot of tutorials. You have self-paced, fundamental straining, which is really good. So please do have a look.

Then we have YouTube channels, knowledge network for asking your questions. And then, do download the handout because it contains a lot more inside information, particularly on how to set up the simulation in CFD, OK? So any questions, guys? I know I've given you a lot of information. I've gone a little bit too fast. I wanted to adapt to the time. Any questions around? Yeah?

AUDIENCE: [INAUDIBLE]

GILBERTO FERNANDEZ: No limit-- node limitations, you mean.

AUDIENCE: [INAUDIBLE]

GILBERTO FERNANDEZ: Yeah. No, there's not really a node limitation in there. We work with, actually, multi cores, so the software works with as many cores as you have in there. All the processes are paralyzed. So now, with the 64-bit technology, we don't have that problem. The only thing, of course, is we recommend-- we have a kind of a rule in there that the software takes a lot of RAM in particular stages. Particularly the meshing takes a little bit, and then the very start of the simulation.

And it takes around 2 gig of RAM per million elements. So you can calibrate, more or less, what your computer, your machine, will be comfortable running. I'm not saying that the other ones won't run, but it take longer, OK? Yep.

AUDIENCE: [INAUDIBLE]

GILBERTO FERNANDEZ: Yeah, if you look at the online help, there's validation for a lot of standard models and, yeah, you can see that it goes really good. Then, in particular, we have also lots of validation within different industries there. We can actually point out to you real examples of people using that. I don't know. For the AEC industry, for instance, we have people doing fire and smoke dispersion, things like that that has been validated with them. Yeah, for instance, for things like valves, pumps, fans. Yeah, it is good. Sorry.

AUDIENCE: What kind of CFD software [INAUDIBLE]?

GILBERTO FERNANDEZ: Yeah, well, it just-- it works separated from Revit. So you have the internal solver of CFD. The particular thing about our CFD is it works with finite element methods instead of finite volume method, which gives us more-- in reality, it gives us a better way of generating your mesh and running that mesh. It allows us to have a mesh that adapts much better to the physical geometry and solve that reliably, yeah?

But in the help, there's a lot of information about the actual method, the actual numerics applied, yeah? We do run an approximation-- a numerical approximation to the Navier-Stokes equations, which are the ones for fluid flow and heat transfer, OK? And on our help, you can follow all the mathematical foundation of it, OK?

AUDIENCE: [INAUDIBLE]

GILBERTO FERNANDEZ: Exactly. Yeah, yeah.

AUDIENCE: [INAUDIBLE]

GILBERTO FERNANDEZ: No, no, no, no, no, no. No, no, no. They were developed by us, yeah.

AUDIENCE: [INAUDIBLE]

GILBERTO FERNANDEZ: Yeah, exactly. They were developed by a company called Blue Ridge Numerics that got acquired by Autodesk in 2011. And from that point, all of the developments have been happening within Autodesk, yeah.

AUDIENCE: [INAUDIBLE]

GILBERTO FERNANDEZ: Yeah. Yeah, it can run compressible flows. It can run things like free surface, things like that. Yeah, definitely. Yeah.

AUDIENCE: [INAUDIBLE]

GILBERTO FERNANDEZ: Sorry?

AUDIENCE: Can you visualize results on [INAUDIBLE]? Like, can you take [INAUDIBLE]?

GILBERTO FERNANDEZ: Yeah, exactly. Yeah, yeah. Yeah, there's actually-- for instance, if you want, if you're interested, there's some really cool stuff. Down at the expo, if you see the Indy car-- the race car-- there's one colleague of mine, James Neville in there. And he runs a sort of augmented reality, and that's based on CFD results, yeah? So you can actually export that.

In that case, you export that as an FBX, yeah? So it's the kind of format that gets read OK in 3DS Max. And then the whole app in there was developed with Unity to do the augmented reality stuff. But yeah, it can definitely be done. And some of the images in there, for the-- I think one of the final ones for the operating room was actually a rendering based on our results. But yeah, it can be exported. You can export-- really, you can export everything. You can export nodal data. You can export a lot of things. But then you can export full files for whether rendering or also things like structural simulation. You can also export that to do FEA on that. For instance, temperatures to do FEA for expansion and stuff like that-- thermal expansion. Yeah. Yep.

AUDIENCE: [INAUDIBLE]

GILBERTO FERNANDEZ: Yeah. The first question was about SimStudio, yeah, the version. I think SimStudio is kind of incorporated into Fusion 360. It's the same technology. So now, the latest versions of CFD come with a Fusion part, yeah? It's mainly-- I mean, if you're used to SimStudio, you go to Fusion, and it's-- most of the things are exactly the same, yeah. But on that, I think SimStudio will not be developed more than what we have now. And in terms of the HPC, yeah, we do that. Yeah, you can actually run what we call CFD 2, or like Scalable Solver. So you can run in multiple computers. So you can run in clusters as well. Yeah.

And you can also-- I forgot to mention that. We have the option of running on the cloud, and there's also one thing which is called Cloud Premier. So it runs in big clusters in the cloud, yeah? So that allows you to run with a lot of power. Yeah.