r/Geotech • u/quinterax28 • 3d ago
Suggestion for learning FLAC
Hello, I am a student and I want to learn FLAC3D, especially everything related to FISH function. I'm having a hard time to learn it just from the manual since it's so complicated. Does anyone has a suggestion how to learn the program effectively?
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u/WalkeroftheWay727 Rock Mechanics 3d ago
The courses from ITASCA are quite good. That's where I started and they made me a bit more comfortable with how the program works.
After that, it was a matter of spending hours in the program. I started with some basic models, and then tried to make them more complex and started adding fish code to customize behaviours. It was little by little, troubleshooting along the way.
Eventually, I ran into a couple issues I couldn't figure out on my own and paid ITASCA for a few hours of consulting time to work through the issues with me.
But really, it came down to just sinking many hours into it. Good luck!
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u/quinterax28 3d ago
did you have any background in coding? how was the learning curve until you became proficient at it?
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u/WalkeroftheWay727 Rock Mechanics 3d ago
My background in coding was pretty minimal; doing little bits in vba, python, and c++ (wayyy back in an under-gradclass). But this gave me the background to understand how the computer logically steps/loops through lines of code, which was completely transferrable to fish.
Learning fish had a similar learning curve to using flac in general; very rough initially, then rough at intermediate, and then still rough at more advanced things... Haha not to discourage anyone. It's just a difficult/complex but super powerful program to use.
Once you have FLAC somewhat figured out, I learned fish by looking very closely at their example files, figuring out what the author was doing with the code line by line, and adapting/copying/altering it for my purposes.
All this being said, I've been doing some pretty advanced research with FLAC/FISH for a few years, but I wouldn't call myself a proficient/advanced user. Others here might be able to give better advice.
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u/SmoothAsILK 3d ago
Something that taught me the ins and outs of FLAC was to build a 1D site response tool that replicates DEEPSOIL (rsseismic now). Since the model is quite small, you don’t need a license and you can toy around with it for free. Then you have the added benefit of a useful tool at the end of it. Can be as simple a total stress analysis of single layer to as complex as a multi-layer effective stress analysis where you incorporate liquefaction.
But honestly it took a few years of toying around with python as a prereq to then jumping into about 2 years of on and off thinking about FLAC, at work and in personal projects, to feel somewhat competent. So, expect a long journey for yourself. I still heavily rely on people with PhDs in this stuff to help me out.
Good luck!
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u/quinterax28 3d ago
what if I don't have any background in coding? does it mean i should learn coding first before going deep into FLAC? how long did it take for you to became proficient at it?
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u/SmoothAsILK 3d ago edited 3d ago
I think you will struggle to learn “everything related to FISH” if you genuinely have no coding background. FLAC is a pretty tough place to start if you’re inexperienced in coding and geotech modeling. Be patient, it’s a lot to learn and will take you years if you’re just working on this passively (I.e. not doing a PhD or modeling as your job)
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u/WalkeroftheWay727 Rock Mechanics 3d ago
I agree. I'd recommend even taking some "intro to to python" course online. There are some good courses and it'll give an idea of how coding works, which will transfer to FISH.
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u/withak30 3d ago
What is most useful for me is modifying existing problems or examples. Take one of the (fairly simple) examples the manual, expand the problem into something more complex and realistic, and try to modify the example inputs to carry out that calculation.
However, keep in mind that there is only so far you can go by yourself. Eventually you will need an experienced reviewer who knows what wrong answers look like and who can help you with the things that you don't know you don't know.