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About Archicad's design tools, element connections, modeling concepts, etc.

ArchiCad and Building Performance Simulation

Not applicable
Hi Everyone!

I was reading with interest topics in this and other forums related with Building Performance Simulation, the last one of course is "Autodesk acquires Ecotect". And in the context of all these issues, I propose two questions for a discussion:

- what is your current experience while designing buildings within ArchiCad environment, doing performance simulation during the design stage?

- And how would you like to see the building performance simulation within ArchiCad in future?


To open the discussion as a fluent Ecotect user and ArchiCad enthusiast, let me share my opinions, mainly focused on future:

I think that in general Building Performance in a pretty tricky thing, as an architects we do want to make the buildings that for example consume less energy, be healthier, look nicer daylit, etc. Yet we are faced with much wider challenges - from site, budget and program considerations, to visual qualities, etc. I really like the description of design process - that the synthesized design solution may be not the most rational alternative, but rather the most successful mediation between conflicts, priorities, concepts and affirmations.

As environmental performance is only a part of this bigger game, I think that for a success it is important to bring it in early, so that it may contribute to design process or even re-shift its direction. To my mind that is where the big success of Ecotect lies - in it's graphical ability to interactively visualise the predicted performance, it's beautiful OpenGL graphics. This interactivity makes incredible difference in communication greens ideas within design process, and also allows for designer himself/herself to loosen the imagination. The second thing that makes Ecotect strong - it's Analysis Grid concept and an ability to export data to specified programms, like Radiance/DaySim, E+ or EQ, or CFD engine NIST FDS (which still is in the stage of wishful thinking) and import results back for visualisation. Ecotect's internal engines on their turn, are not so strong, at least I wouldn't recommend BRE Split_Flux to anyone who is doing toplighting or indirect reflected lighting.

So in future I would also like to see these two components, only in much clear and stronger way. The 1st is constant re-evaluation of performance with credible software, starting from early stages and clear. And the 2nd beautiful visualisation of these results while doing the design process in ArchiCad. And good support in interpretation the results and helping setting up multifaceted criteria, as this makes Building performance simulation right now difficult accessible. Let's see how the connectivity between ArchiCad and Ecotect/GBS/whatever will develop via IFC/gbXML.

Yet, after acquiring more experience with AC, I would like to see ArchiCad having it's own Simulation capabilities. I think that AC already has incredibly much for that it - all AC interactive 3D visualisation capabilities, modelling capabilities, definition of external envelope and zone concept. Only missing part is good simulation engines themselves (which, for example Ecotect, doesn't either, only export/import). Maybe the same external freeware programs like Radiance/eQUEST can be used for that, or maybe their algorhytms can be integrated within AC. And similiar to Sheets that update automatically, once model is more detailed, the user can set up list of automatic simulations - for example: 1st simulation Illuminance on overcast winter day, 2nd - thermal comfort in sunny summer day, and 3rd - luminance distribution in summer day. Thus, once he/she deals with one of the issue, he/she automatically get feedback, how the other is changed. And this "sheet concept" of incremental development allows to have the different environmental awareness in different design phases. In schematic that would be more based on rules on thumbs and nice plan/sectional diagrams showing for example how air-flow might perform, but later, these intents could get quantified and compared.


I'll be glad to hear other opinions and thoughts.

Zigurds Greivulis,
Not applicable
So, no replies so far?

Yet, I know that people ARE using ArchiCAD for a design of sustainable buildings where Building Performance Simulation is happening, in one way or the other, and how does it happen?

Does it happen in the traditional manner, that architects, when they draw building diagram, just have in their mind a couple of strategies for optimal building performance, and in this process these ideas already become so integrated and tied with the rest of building, that actually it is only the work of consultants, who can make work these strategies better, but not much in architecture can be done afterwards, when the first diagram is drawn?

If that is the case do you use ArchiCAD sheets just to draw diagrams that explain these strategies to the others, e.g. you use ArchiCAD just for communication?

Or are you giving you ArchiCAD model to the consultants (or course, one needs a lot of knowledge and experience for credible simulations), and are they performing the calculations on that? Or do they make their own, simplified model? And when does these calculations happen - at early stages, or at final? And what impact these calculations make on the design?

How do you set up criteria? I know that f.e. LEED is multifaceted, thus pure Building Performance Simulation covers only smaller part of all issues where LEED credit can be acquired? Does other internal criteria is used? I think that can be the area for software to be used - helping setting up criteria and checking wheteher they are achieved.

And what about future? Should Building Performance Simulation be more integral part for example for Architect's BIM application, or just in opposite - that's the other area, where other specialists are working, and what only matters is the communication between them - model i/o, allowance to i/o results and ability to display them in a clear and understandable manner?

I think these issues can be interesting for everyone.

Not applicable
First of all, I'm really not the right one to answer these complex issues you are asking and proposing, because I've only been working with AC for 3yrs.
even though I am a "certified green builder", (for whatever that's worth).
Many of the things I think you said can be set up in AC, but at what cost of time? I say, set the stage in AC, and let specific specialist work on specific issues. That way the total package will be more accurate and complete.
With AC12 now being able to address multi-core processors, the future of features is surely going to be increasing, by leaps and bounds...stay-tuned!
The totality of what you have written should be looked at by more specific
categories instead of mixed together. In other words, broken down for each of the complex issues you brought up.
This would probably get you at least some knowledgable answers in specific
Good luck,
Not applicable
Bier, thanks for your thoughts. I know it is very wide topic, but actually, I wanted rather to hear more general views than specific nuances. What I understand from your response (and from the latest ones in "Autodesk acquires Ecotect") is that one can pay more attention to performence simulation, but "at what cost?", e.g. anyway there is a need for consultant, who will use his/her own software package, and there is not a huge need for direct integration of simulation within architectural package.

In my personal experience, designing of daylit building using Ecotect/Radiance, is a pretty wild "free-style" process. That means, of course, there is a needed for exact studies of daylighting itself to build up my competence, and of Ecotect as well, to ensure certain degree of credibility. But once specific design was going on, the only thing Ecotect helped, was to get results faster and make more design iterations. When simulations were done, it was completely up to me how to interpret them, how to do it in the context of other design decisions, and how creatively shape process further. So, the human role in all this was very huge.

Yet, even in architect-consultant (and consultant uses different software, not AC) model there are at least two important issues now:

1. Import/Export of models. What software is used and how can ArchiCAD models be imported into these software easily? My experience with Ecotect is that in the beginning I was thinking to model in SketchUp and import in Ecotect via 3DS, but that was very bad idea, as all material assigments, etc got lost. As a consequence I modelled everything within Ecotect (~20000 objects at the end 😉 ) instantly setting up material properties - as thus acquired speed, as could make simulations at any time without delay required for i/o.

2. Visualisation/Communication of results. Ok, consultants make credible simulations, and gives some suggestions, but it is very important for architect to visualise it within his/her spatial diagram of building (for example airflow image at - Ecotect has great "Analysis Grid" that allows to import back for example Radiance results, and I wish something similiar would be in ArchiCAD too - import of simulation results to make cool pictures. And there is already great OpenGL graphics with 3D cuts within ArchiCAD

Zigurds wrote:
- what is your current experience while designing buildings within ArchiCad environment, doing performance simulation during the design stage?
Dear Zigurds,

As an example touching what you discuss...the Swedish company Strusoft has a plug-in for ArchiCAD where the architect chooses energy parameters for his/her building and surrounding and exports them to a server application which sends an email back to the architect with an appropriate calculation of the energy status of the building. It's intended a an easy and fast tool that the architect can use to check the validity of a design (new design or wall construction...export and get the feedback directly etc etc. When doing the full energy simulation they (the builder or owner) go for the expert programs like VIP+ but vipweb ensures you're on the right side without having to be an expert.

Having a BIM tool like ArchiCAD is good but the working process needs to support BIM as well and I feel were not there yet.
Some architects here export IFC models from ArchiCAD to Riuska with success. BIM islands emerge here and there...mostly around ArchiCAD-Tekla-MagiCAD.

It's the same question about other special areas....rendering, acoustics, facility management, structural etc. Where is the multi-do-it-all person or organization or partnering concepts? Local differences occur of course.

The road needs to be paved before we can go really fast...

Best regards from the Swedish best-(west)coast,
AC 25 SWE Full

HP Zbook Fury 15,6 G8. 32 GB RAM. Nvidia RTX A3000.

Yours is a most relevant question, and I was hoping for a greater response from those currently using building performance software (or perhaps they are too busy using it...!)

Having almost been seduced by Ecotect a coupe of years ago, my desire to use such software has been re-ignited by my current work. What is your current opinion of Ecotect, and how are you using it (if you don't mind me asking)? Do you find it useful, quick, and easy to use (particularly at the conceptual stage)?

At first sight, the graphical interface appears to be a God-send for communicating such matters to clients, consultants, and contractors.....

The Ecotect website is very seductive, but I have fallen into that trap before....... (although it would not hurt Graphisoft to learn a few marketing lessons from the better websites - an old subject, I know).

Your experience, and some feed back from current users of such software would be most welcome....

Thank you.
AC27 Apple Silicon. Twinmotion.
16" M1 Max MacBook Pro 32GB, Apple Studio Display, MacOS14
Not applicable
Sure, PB!

I think that a good way to summarize my experience with building performance simulation and specifically Ecotect can be done also by an article "Organizing the Development of a BIM", posted somewhere recently on the forums (

It is a very interesting article that propose 5 levels of detalization for BIM model, and also what awareness of environmental performance might be in each one of them.

The first stage is concept, and as appropriate level for awareness of environmental performance is a) Criteria and b) Strategies. I think that the Criteria is extremely important. I have seen a lot of scepticism towards BPS and to my mind one of the biggest reasons is the difficulty to set up reasonable criteria to strive for. Without it the usage of BPS can be pretty meaningless. So, Is criteria just a code compliance for one specific aspect of design, for example - exceeding minimal daylight factor, or is it more holistic environmental analysis - balancing daylight factor with heat gains/losses, visual comfort, visual connection, etc. In the second case the criteria is multifaceted, which can be really challenging. I think that it is also the first stage consultant comes in, if neccessary, and gives a hint what criteria is appropriate for the given program/climate.

Strategy relates to these nice diagrams with arrows (air-flow, light) that show the intended performance. But for sure, environmental design strategies are part of greater design strategies, and are in constant dialogue (or one can also say - in constant fight) with them.

For the first stage Ecotect (or AFAIK - any other BPS tool right now) can not help you at all. Well, actually Weather Tool can help in the analysis of climate date. But otherwise it's completely up to you, your client and people you are working with.

I've used Ecotect for the 2nd and 3rd stage - schematic design and more detailed design. And it is reasonable once criteria are set up. I was conducting the roles of both architect and consultant and it was fun. But certainly there can be and more likely will be two parties, not one. Analysis done in the second and third level can lead to reconsideration of criteria and strategies.

Yet, when I am referring to the stages, I refer to general logic of design development and not BIM model development. AFAIK it's still difficult to import BIM model into BPS software and vice versa. There are also conceptual issues - like for energy analysis detailing is not neccessary, however for luminance analysis - it brings more sense of realism, so conversions perhaps is not straightforward, but should be done skillfully.

HTH and... Good luck!
Thank you Zigurds for your considered reply.

I must admit that at first I thought that we might be talking slightly at cross purposes. But having followed the link you provided, I stand corrected.

Your perspective of the matter is somewhat broader than mine, but I now appreciate that what I was seeking to ask was how well Ecotect (or an other software solution) integrated with ArchiCAD to provide easily interpreted visual feedback particularly at detail levels 100-300.

Perhaps if I give you some more information I will make myself clearer: Having graduated from a university that had a strong emphasis on building performance (thermal/lighting/structure/etc) I felt that my appreciation of these aspects of building performance was acceptable. However, in professional practise, any detailed building performance analysis is only performed at the later stages of a project design, and even then only if the project size & budget is deemed to warrant the expenditure of the 'extra' time & money!

Whilst I received a good grounding in the calculation of lighting & thermal performance, it is far too laborious & time consuming to carry out such calculations manually, particularly for the majority of our work whose budget would not support it. As with all the architects I have encountered, our designs take form from an intuitive/past-experience appreciation/application of thermal/lighting principles.

However, with the welcome current emphasis on more performant buildings (and houses/flats in particular in our case) I would greatly appreciate a software solution that is (and will remain) 'seamlessly' integrated with ArchiCAD that provides a rapid graphic feedback on design from the early stages. For example:

Initial design form: (levels 100-300)
- analyse sun shadows, wind modelling, internal natural daylight levels of at different times of day/year at any geographic location.
- Assuming given wall/floor/roof/window constructions/performance estimate building heat loss (to gauge against mandatory requirements).
- Auto, or one-step, update of this analysis following modifications to the BIM
- Idealy the software is sufficiently integrated so that once certain parameters are set-up (component U-values for example) the building analysis can follow in real time: In the same way that when a wall is moved on the AC floor plan, the change is reflected in the section/elevation/3D windows, then that same modification of the wall in the AC floor plan is updated in the thermal/daylighting/wind analysis windows & reports...

Detailed design: (levels 300-500)
- As the design is refined the thermal/lighting model follows seamlessly:
- Construction elements are specified in greater detail & their performance parameters are updated
- As the design evolves the effects of each and every change in the BIM can be (almost) instantly gauged in the graphic/numeric feedback from the building performance software (made possible by recent multi-core, multi-threading, 64 bit hardware & Operating systems with access to large amounts of RAM).

My understanding is that such integration is not yet available, but it must surely be a high priority objective for any BIM software provider that wishes to steal a huge advantage in the current market place...

Furthermore, since most architects/designers are graphically orientated, a graphical interface following Ecotect's lead would appear (at least to me) to be essential.

When I finally find the time (and courage) I shall try out Ecotect, but it is far from straight forward since the software is windows only.......

Meanwhile, do you find yourself always using Ecotect at the very early design stages to assess window layout & form, room depth, building layout on the site, etc, or is it still too cumbersome to be used for each project? And, thank you again for your time.
AC27 Apple Silicon. Twinmotion.
16" M1 Max MacBook Pro 32GB, Apple Studio Display, MacOS14
Not applicable
Opened up Building Products News today while having a coffee and read about LCADesign which is software that calculates life cycle costs/environ impact etc- looks interesting. Just need to export from 3D model in .ifc format (Industry Foundation Classes) from Archicad or Revit etc

Anyone know anything more about this? Link below

PB - is that a 748 or a 916 you are on? I have a 748R myself so my boy can't sit on the back like he used to on my Monster

Thanks for the link....

The red toy is my 748BP: Great fun - just waiting for some drier weather (I'm in the south of France). I was sorely tempted by the 748R, but since it was to be my first bike I decided to be reasonable..........that was 8 years ago, and I'm still delighted with her!


AC27 Apple Silicon. Twinmotion.
16" M1 Max MacBook Pro 32GB, Apple Studio Display, MacOS14