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Ask HN: 3D physics simulator to fix custom wooden table

3 points by etamponi ↗ HN
Hello everyone,

When I am not working, I like to play the carpenter... Yesterday I finished building my first folding table, with a custom design I was so proud of. Unfortunately, once I was done I realized that the table is very wobbly. It looks like something generates a lot of torque on the legs (made of wood). I tried to make them stronger by adding some steel plates, but it didn't work.

Before attempting more fixes, I'd like to simulate via software what would happen (for example: replacing wooden legs with steel legs). But I don't know of any 3D physics engine that would allow me to do this kind of simulations.

Do you know something that might help me?

4 comments

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[dead] thendrill
You need some kind of advanced cad that has torsion and stress simulation. Something like full solidworks or Catia. Problem is it takes som much time and knowhow to setup the simulations that you might as well just keep trying and failing physically. Eventually you will gain more insight how forces would distribute in the material, and the know how of what works and what doesn't. Bottom line... Hands on experiment always beats a simulation
dekhn
Go back and read basic woodworking texts because these are the sorts of things people have been solving for many years in a physics engine isn’t really going to speed up the process
etamponi
I don't think this specific thing I am trying to solve is covered in a basic woodworking text. The table contains moving parts, and at this point I am trying to fix an existing design... But sure, I'll try that too! Thanks :)
dekhn
Ah. I see- like a kinetic structure? I think Fusion 360 could probably help with this, but even better is blender. Blender contains 3D physics engine that can operate on models with constraints, so you'd basically just build a 3D working model of your moving parts table, and "simulate" it by moving parts along constrained paths. Then put a floor under it and measure the angles of the bases of the legs (assuming that's what's wobbly).

I was assuming you were just hitting the "it's hard to make a 4-legged table sit flat" or the "keeping attached legs attached firmly" problems.

Fusion 360 would add the ability to do FEM simulations, so in theory if you're torquing wood hard, you could see where the weakest point is, and add more material.