Can't see curtain walls in Ecotect

[cateramella]

Hello,

I created a 3d model of a house on Revit.

The problem is that when I import it into Ecotect I can't see some curtain walls. I used the the curtain wall tool to draw them.

The odd thing is that some of the glazed curtain walls are visible and some not even though I drew them using the same method.

Does anyone know how I can solve the problem?

Thank you very much for help.

Caterina 

[Pennetier1]

Hello Caterina, 

I am curious whether or not the curtain wall properly appears as a DXF file - can you open it in AutoCAD or another software to see how that comes through? I assume you did export as a DXF, or was it a gbxml format?

You can send me your file and I can have a look at it.

Cheers,

[cateramella]

Hi,

I haven't solve my problem yet unfortunatly the curtain walls didn't appear properly. I tryed in many ways:

DXF: not all the curtain walls were imported and they were in the wrong place

gbxml: the model is more defined but still without the all curtain walls.

I also tryed to import the house without the curtainwalls in gbxml and after to import in this file the curtain walls in DXF but they are only few and not placed in the correct place.

Besides there are other problem: the roof in separated from the walls and some of the floor aren't imported.

My aim of is to perform the energetic analysis of Fallingwater using only the detailed 3D model built in Revit without using the mass model tool.

I send you the xml file.

Thank you very much for your reply

Caterina Ramella

[cateramella]

Hi,

I thought to have find a solution converting the file through the plug-in as STL.

In this way I can see the house in all of its part even curtain walls are imported but Ecotect doesn't recognize them as window and I can't run any kind of analysis.

When I tryed to run the solar access analisys appeared this notice "floated points overflow".

I enclose an image of STL format file

Caterina Ramella

[Pennetier1]

Hi Caterina, 

This is definately not the way to go for any thermal analyses as your model is much too complex for any useful studies - terrain, trees and other very detailed objects will slow down the whole process and not give you much more detailed results.  Instead, you want to simplify your model to simple zones with glass apertures.  In that regard, gbxml does a great job, but there are a few caveheat as you noticed:

For one, you have to be pretty strict with your Revit model.  For example, make sure that roofs are not made of floor or slab elements etc... 

It looks like Revit does not recognize the curtain walls when exporting as gbxml; can you confirm that in the gbxml export window of Revit prior to the export? If that is indeed the case, you may have to modify your Revit model (or create a new file specific to your thermal modeling export) so that it utilizes regular windows rather than curtain walls objects.

Another method I have used in the past, is to use a dxf or gbxml file into Ecotect as a background only and recreate only the simple volumes (thermal zones) of your building and location of glazing.  That is more time consuming in theory but in practice, too many users spend much time trying to correctly export their Revit model into Ecotect so they have to spend just as much time. 

Keep your model very simple, think "shoe boxes" with windows.

I am currious to know whether your curtain wall appears in the dxf - not once you import it into Ecotect but in a different software that reads dxf?

Let me know if that all makes sense.  I have done the same exercise that you are doing with the Farnsworth house which was much simpler to model!

Cheers,

[cateramella]

Hi Olivier, 

I confirm that Revit doesn't recognize curtain wall properly when exporting as gbxml. For example it recognizes some of them that go from the floor to the ceiling but not those that rest on the wall (I mean when I have half wall and half window) and I see a wall from top to bottom.

Reading on websites and internet forums I understood that the best thing to do is to semplify the model as you suggested and I am going to do so not to spare any more time and in order to have useful studies.

I am going to keep my background (trees and topographic surface) in dxf because it is shaped as mass object.

Before starting to build the second model I would like to ask one last thing: you talked about a model created by thermal zones (which I created in the model you saw amyway) but I also read that I can create one by mass.I guess they are two differt way to have a simple model to be exported.

In your opinion which of these two kind of model works better in Ecotect?

Really grateful for your help

Caterina Ramella

[Pennetier1]

Hi Caterina, 

I am glad that made sense.

You can certainly create a mass to be exported - the thermal zones I was refering to are the ones created within Ecotect, not Revit.  I think that will keep things much simpler, however, you can also create simple building element with floor, walls, roofs and windows and export as gbxml so that you will have the right location for your windows.  

Also, keep in mind that it is possible to import various files, such as gbxml and dxf into the same Ecotect model, and everything should fall in the correct place.

So that you can create a simple model in Revit for your building only, export that as gbxml, then import your trees and terrain from your dxf in the same model.  Should work!

Let me know if you have more questions on this topic, otherwise please accept as a solution so that others can benefit from this information.

Cheers,

[cateramella]

H Olivier,

I have begun my mass model. I just wanna be sure that the method I am following is correct.

Starting from the dwg file I started to trace the walls with the "in-place mass" tool. Now they are plans with no tickness to which I assigned the material. I built the floor in the same way. I can't save the file in xml because I didn't put any "room bounding elements" yet.

Is what I am doing ok?

I enclose an image of the mass model.

Thank you very much.

Caterina 

[Pennetier1]

Hi Caterina, 

It looks like you are doing this within Revit?

I was more thinking about doing that within Ecotect, whereas you import the dxf geometry, then within Ecotect you use the "Zone" Tool to trace your rooms.  In that way, it creates automatically thermal zones with roofs, floors and walls at once.You'll then have to add windows where they belong.

The only way to do this properly within Revit would be to use the Room tool then export as gbxml. You do not need to assign specific material in Revit as you will need to recreate and assign thiese materials in Ecotect anyhow.  That is why you might as well create your zones within Ecotect.

Let me know if that makes sense,

Cheers,

[cateramella]

Hi Olivier,

I am sorry if I have not written before but we worked to find a solution.

At last we decided to convert the curtain walls in windows using the window family in Revit as you suggested. In this way all the windoss are now visible in Ecotect.

We are using this model to run the solar analysi and it seems that the results we get are plausible.

We have also drawn a simplified model using the mass model tool (always in Revit) to do the thermal analysis that we haven't try to run yet.

Then we tried to run the solar analysis adding the toposurface and trees exported in .dxf but the pc doesn't work properly, it is too slow. After three hours the analysis was 0.3% out of 100%(!!!).

So we are searching another way to make the trees lighter. We have put a 2D tree in skecth up and import it into Ecotect as a .3DS format but the pc still doest't work. The file probably is too heavy..even try with only one tree, for test

We are interested to have simple shapes for trees to be able to calculate the daylight factor's reduction. How can we do? Is there a solution?

I enclose an image of what we have obtained right now.

The best would be to have the toposurface too but I guess I'm asking too much!

Thank you very much.

Caterina

[Pennetier1]

Hi Caterina, 

Thank you for following up with me.  I am glad you are working this out.

A couple of things to make things easier on you...

1. TREES:

Your tree as imported from Sketchup is still way too complicated: I think it is made out of hundred of lines.  Remember Ecotect is very sensitive (from a computation time process) to the number of objects in your model, because it has to go through each and every one of these objects to determine wether or not it will be shading other objects in your model.  So you want to simplify as much as you can.  I am attaching an .eco file of a typical tree construction that I use in Ecotect.  It is really a simple plane that I trace on the floor, then flip it vertically , duplicate it and rotate 90 degrees.  It does the trick with only 2 objects.  Assign a tree material with the appropriate transparency (depending on winter conditions or summer conditions, that transparency might change).

2. THERMAL MODELING:

Looking at your attached image (is that the thermal model?), I suspect quite a few errors coming from your Revit file; you should really have very clean and simple, fully enclosed zones.  There should not be any floating objects unless they are on the Shading devices zone.  In that regard, I would go back to your Revit file and make sure you are creating the Room objects correctly.  See the attached paper that discuss how to create these Room objects correctly in Revit to be exported as gbxml into Ecotect.  I hope that will help.  This model should not take too long to calculate.

3. TERRAIN:

I used to construct the topo within Ecotect itself, but I have found that importing from your CAD (Revit or other DXF) works quite well if it isn't too complex.  You might want to simplify as much as possible once imported.  Also, if you feel that the terrain will have little impact on your results, it may not be necessary at all.

Remember, keep things simple, and use your results for comparison study - comparing one design option versus another one.  No thermal engine will give you exact results in the end (because they are all based on averaged weather files and thus it is always going to be a "best guess" scenario). Ecotect is great for quick comparisons of design options, not so much to size HVAC system or calculate accurate loads.  For that, you would need other software such as EnergyPLus, EnergyPro or even GBS can be useful here.

Again, I hope this helps a bit.

Cheers,

[cateramella]

Hi Olivier,

thanks to you, your advices are very useful.

The last image you saw was of the detailed model that we are using for solar analysis also for that reason it is more complicated. Thanks for the "revit userguide" you attached, it is the same we used to make the room boundary weeks ago.

For both models (detailed and mass) we decided to use the topo and trees shaped for mass in Revit and exported in Ecotect as .DXF.                         What we have done now is to assign the "material properties" of your "simple tree" to our landscape... And Ecotect seems to work quite well. I enclose an image of that.

I would also ask you about the thermal model.

It is built in revit with mass, so if I did things in the wright way it should be simple. Then I added the materials we created in the library and I run the inter-zonal adjacencies. Ecotect reported me some warnings (1045 or 1050 I don't remember properly. They concern the alternate material didn't match with the primary )that I tried to adjust.

First to run the thermal analysis I have got a new question: the thermal analysis grid.

Looking at some website they say it is necessary for this analysis. I was able to make the grid appear but just in the first floor. I am wondering if it is necessary to have it also in the other two levels.

In that case, how can I do? Is it possible to have three gryds in the same model? I attach an image to show you what I could do.

One last thing concerning the weather data file.

Is it possible to change the umidity value in the .wea we chose? (firt .wea of Pittsburgh than Altoona Blair County because the altitude was more similar to Fallingwater). We think that in Falllingwater it is possible to reach 100% of umidity at the floor level.

Really greatful for your help

Caterina

[Pennetier1]

Hi Caterina, 

It looks like you are almost there....

Let me answer your questions here. 

1. ERROR WITH ALTERNATE MATERIAL (1045)

This is a little understood feature of Ecotect. Each object in the model has two material assignment: a Primary material and an Alternate material.

The primary material is the main material of the object and is what Ecotect uses when that object is NOT adjacent to another object.

When an object is adjacent to another object, as determined from the inter-zonal adjacency calculation, Ecotect will use the alternate material assigned to the object.  The reason for this is to be able to move around zones without having to re-assign materials to the objects.

If you create a zone on top of another zone, then a FLOOR object is adjacent to a CEILING object - they have two different primary materials and Ecotect does not know which one to use for the calculations.  So It looks at the Alternate material, and this alternate material has to be the same for both objects.  So what you want is is to have the alternate material of your FLOOR object be the same as the alternate material of the CEILING object.

Same idea with WALL elements. Two walls might be brick material, but once they are adjacent to one another, it might really be a simple partition material between the two zones, so make sure your alternate materials are the same.

There is an option to have Ecotect do this automatically when going to User Preference (Crtl + Shift + P) > Fixing Links Tab > Automatically fix Alternate materials.

2. ANALYSIS GRID

You do not need the analysis grid for thermal calculations. Only for solar access, light, comfort, and visibility analyses.

All thermal analyses are done through the ANALYSIS page on the left side of your screen.

Press F1 to enter the help menu > under contents navigate to > Analysis > Thermal Performance > How Do I...  This will highlight some of the most common thermal analyses calculations available.

3. WEATHER FILE

Looking at my map, I see that Falling Water is closer to the town of Margantown, only 30 miles away to the southwest.  That is the weather file I would use instead of Pittsburg.  Ultimately, yes, it is possible to change the humidity data of your weather file, but it can be time consuming. Alternatively, you can create your own weather file wiuth a spreadsheet if you have hourly data for the entire year.

I hope all this helps.

Cheers,

[cateramella]

Hi Olivier,

here I am with a copple of questions!

After having run the thermal analysis we would like to understand better what the diagrams show us, in particular how the solar gains are calculated.

Looking at the graph of "Hourly heat gains/Losses" of the coldest peak day there are some values called "SolAir".

Do these values refer to the sum of the gains through the opaque walls and windows? Or are values ​​that have been multiplied by a damping factor? Just to understand if they are calculated as the Italian norm.

This question showed up because our professor didn't see any value referred to the capacity per unit area (capacità areica in Italian) KJ/mqK.

Can Ecotect calculate the energy dissipated in the vault? We checked but we couldn't find anything in this sense.

Thank you for your time.

Sorry to bother you again.

Caterina

[Pennetier1 · Accepted solution]

Hi caterina, 

No bother at all.

The value "SolAir" refers to the heat gains into your space that are caused by the solar radiation heating up the exterior surface of your building, thus increasing the outside temperature and increasing the conduction gains.  So in effect, SolAir gains can be thought of as a form of conduction heat gain that is caused by solar radiation alone (rather than typical conduction gains that are caused only by difference in air temperature).

These SolAir gains can vary with the reflectivity (color) of your external surface as the sun will be reflected more readily on highly reflective surfaces than dark surfaces and thus will reduce these SolAir gains.  The thermal capacity of your assembly will also affect SolAir gains. 

In Ecotect, the specific heat capacity and density of the materials that make up your assembly will combine to create what is called "Admittance" of that assembly. Therefore, adjusting the admittance of your assembly will affect the SolAir gains.

See the Hourly Heat Gains > Thermal Mass topic of the Help files for more info.

I do not understand your question regarding the vault - what is the vault?

I hope that helps.

Let me know if you have more questions on this topic, otherwise please accept as a solution so that others can benefit from this information.

Cheers,

[Daisy_]

Hello Pennetier,

Thank you for your responses on this thread. Quite infomative!

Please allow me to take you back to the Primary and Alternate Materials question. I am modelling a building in ecotect for thermal analysis and I don't quite understand that bit. I have two zones overlapping. The primary material of the ceiling of Zone below is specified as Plaster_Insulation_Suspended while the Primary material of the floor of the zone above is ConcFlr_Timber_Suspended. How do I go ahead and assign the alternate material. And does this alternate material affect the results of the analysis?

Please help me.

Thanks.

DAISY.

[Pennetier1]

Hello Daisy, 

The basis for the alternate material is for when two or more different surface materials are overlapping, as in your case. So...

When the object is not adjacent to any other object, Ecotect uses the PRIMARY material.

When the object is adjacent to another object, Ecotect uses the ALTERNATE material.

The reason for this is that if two different objects are adjacent to one another and have different materials, Ecotect does not know what material to use.  In reality, there would only be one material.  So Ecotect will use the ALTERNATE material, even though the PRIMARY material may be different.

If your Roof object PRIMARY (and most likely ALTERNATE) material is a ROOF material, and is adjacent to a Floor object that has a PRIMARY and ALTERNATE FLOOR material, Ecotect would likely display an error message, telling you the alternate materials are different and thus Ecotect does not know which assembly to use for the calculations.

To fix this, a few solution:

1. Select your FLOOR material and change its ALTERNATE material to the same material (ROOF) as the roof object it is adjacent to.  To do that, I like to select the object and go to the Selection information control panel, and edit the 3rd entry down from the top "Alternate Material", in your case, make the alternate material of your FLOOR the same as the ROOF material of the object below.

2. You can set Ecotect to do this automatically in the background so you don't have to mess with anything.  Go to the User Preference panel (CRTL + Shift + P) > Fixing Links tab > Automatically Fix Alternate Material For Adjacent Surfaces.

Doing so, Ecotect will use the Alternate material assembly for the calculations.

For more in-depth info on this, open the Help files (F1) and type "Alternate" in the search box > select Material Assignments topic.

I hope this makes more sense!

Let me know if you have more questions on this topic, otherwise please accept as a solution so that others can benefit from this information.

Cheers,

[Daisy_]

Pennetier,

Thank you very much for your response. It makes sense.

So, will the alternate material affect the thermal calculations, say for example the respective Fabric gains in each zone? Or, will Ecotect go ahead and use the primary material at the overlapping zones?

I'm new in Ecotect, so I'll most likey get back to you with many more questions. 🙂

DAISY. 

[cateramella]

Hi Daisy,

I started to use Ecotect few months ago so I am not an expert as Pennetier! 

From my experience I can tell you that the alternate materials affect the thermal calculation infact for the Fabric Gains calculation Ecotect takes into account:

1 thermal transmittance

2 surface area of the wall

3 difference between indoor and outdoor temperature

Ecotect automatically identifies the overlapping surfaces (by the calculation of the Internal-Zonal Adiacency) and assigns them their Alternate materials.

I hope that what I told you is useful and correct!

Caterina

[Pennetier1]

Hi Daisy_, 

Caterina is spot on.

When two surfaces are adjacent to one another, Ecotect will use their ALTERNATE material assembly and thermal properties for all thermal calculations.

Only the surface areas that are adjacent to one another will use the thermal properties of the ALTERNATE material; the rest of the object that is not adjacent to any other surface will use its PRIMARY material properties.

One of the reason for this is that sometimes, you have two zones with a primary material of say, BRICK_WALL (exterior type of assembly), which is fine when they are not touching each other.  If you put these two zones next to one another, you can assume that the area of the walls that are in common with the two zones would most likely not be a BRICK_WALL assembly, but rather something along a PARTITION_WALL (interior type of assembly); thus if the ALTERNATE material of the two zones is PARTITION_WALL, anytime the two zones are adjacent to one another, Ecotect will use the PARTITION_WALL assembly property to calculate thermal gains and losses.  This allows the user to quickly move around the zones of the model without having to constantly changing and re-assigning material assemblies.

The same idea applies to floor and ceiling type of assemblies.  A zone would have a floor assembly, but if you were to move that zone above another zone, that floor assembly would become, in reality, a ceiling assembly.  Thus you assign that ceiling assembly as an Alternate material of that floor object.

I hope this clarifies things a bit further.

Let me know if you have more questions on this topic, otherwise please accept as a solution so that others can benefit from this information.

Cheers,