4 ms·

Show HN: Physics-based CAD

104 points by lochieferrier 10y ago

ade2 10y ago
Interesting, do you have some more info about how it works? When I make the battery larger, is it considering the weight of the battery? Weight of motors, props, etc?
- lochieferrier 10y ago
  Yes it's considering the weight of the battery, as well as the weight of the motors. It doesn't factor in the props, I didn't get around to that. The props have inaccurate geometry of course, which I'm looking to fix with a mesher. Have a look at the console for how the geometric program is assembled.
  - ade2 10y ago
    Cool. I think this tool has a lot of potential users, especially if you can make it pick between commonly available props, esc, motors and so on. Imagine how cool this would be if it could make a list of those things and export a 3d-printable frame :)
sheer_horror 10y ago
I managed to break the tool by inputting some infeasible inputs and then changing them again several times, and then refreshing the page.
- lochieferrier 10y ago
  This is my first time putting something up, everything is breaking, fixing it now.
  - oneel 10y ago
    No test like a production test.
garyfirestorm 10y ago
That page is broken
- Hydraulix989 10y ago
  Slashdot Effect probs
  - lochieferrier 10y ago
    Nope, I just have no idea what I'm doing.
    - duncan_bayne 10y ago
      hugs Takes some balls to go live with a project when you're on a step learning curve. Congrats :)
      - lochieferrier 10y ago
        Fixed it, didn't know about pythonpath with gunicorn.
    - huhtenberg 10y ago
      That will pass soon enough.
bnegreve 10y ago
Cool, I think more applications should be using solvers like this. What solver are you using? Is it solved server side?
- lochieferrier 10y ago
  Currently solved server side, though assembled on the client side (see console) with gpkitjs and then passed through to GPkit. Packages here: https://github.com/lochieferrier/gpkitjs https://github.com/lochieferrier/gpkitjs and here: https://github.com/hoburg/gpkit https://github.com/hoburg/gpkit Geometric programs are super cool.
frik 10y ago
It's called parametric modelling, and many CAD software use a parametric kernel (solver). https://en.wikipedia.org/wiki/Computer-aided_design https://en.wikipedia.org/wiki/Computer-aided_design Is this somehow different? Please explain
- lochieferrier 10y ago
  The difference is that there is a simple physics model that's driving the dimensions. So the arms are getting resized according to beam bending, the battery is a certain size for the energy requirement, motors are sized by kw/kg and kw/m^3 and so on. There's definitely ways to make this sort of model in something like Solidworks through the use of a variables interface that interacts with the drawing dimensions. Though it can't do any sort of fast optimization with the physics relations. What's happening here is a guaranteed global optimal design is being returned for a given set of inputs and objectives in a few seconds.
  - veeedz 10y ago
    This sounds interesting but I can't react the site. Could you please explain how you get a guaranteed optimum? What if you have conflicting objectives?
    - lochieferrier 10y ago
      I think by react you meant react to, which was fair enough, it was dodgy as. Now running well. The property of getting a guaranteed optimum is something that arises from setting the design problem up as a geometric program. You won't always get a solution (for example, a certain size quad has a minimum prop diameter). Though if you do, it is guaranteed to be optimum because the problem is convex as outlined here: https://gpkit.readthedocs.io/en/latest/gp101.html https://gpkit.readthedocs.io/en/latest/gp101.html Also, conflicting objectives are naturally traded off until you find a Pareto optimal solution. Using geometric programs lets you balance conflicts in a design quickly. This is why they are super useful for aerospace applications, where you are always looking at a tradeoff between weight and at least one other variable.
doczoidberg 10y ago
this is more a configurator than a CAD.
kylestlb 10y ago
Nice project. What are you hoping to add in the future? Our team works on goal directed design as well, but at the moment it's less of an interactive optimization tool and more of an involved job running process a la Optistruct. One of our fun projects was a drone body as well :) link for the interested: https://autodeskresearch.com/projects/dreamcatcher https://autodeskresearch.com/projects/dreamcatcher
- lochieferrier 10y ago
  Wow, that is really beautiful. Topology optimization is cool stuff. I think it's key for optimization to be fast so that the designer can get a feedback loop going between the computer and the ideas in their head. Would love to talk about whether geometric programs might help Autodesk generate topology faster. Near future stuff is probably a real-world component input (optimized shopping), and making things more flexible so you can drag and drop something together from components.
diegoandrade 10y ago
This is not Physics-based at all, you need to introduce other variables like wind speed around the drone, the direction of the wind, angle of attack, viscosity, etc. This example is parametric modeling at best or a configurator, not saying that is bad, just has a misleading title. I do not see any real geometry manipulation or groundbreaking CAD being attempted. Here is a viewer that Autodesk released this year using javascript. https://developer.autodesk.com/ https://developer.autodesk.com/
- lochieferrier 10y ago
  For sure, there's a lot missing, title is probably misleading. Definitely nothing new in terms of the CAD, browser CAD has been well done, just look at professional products like Onshape. Right now it's primitives only for this, one of the next steps is to look at how full meshes can be optimized. A simple example of this could be wings: https://people.eecs.berkeley.edu/~pabbeel/papers/2013_gp_wind_turb.pdf https://people.eecs.berkeley.edu/~pabbeel/papers/2013_gp_win...

104 points by lochieferrier 10y ago

ade2 10y ago

Interesting, do you have some more info about how it works? When I make the battery larger, is it considering the weight of the battery? Weight of motors, props, etc?

lochieferrier 10y ago
Yes it's considering the weight of the battery, as well as the weight of the motors. It doesn't factor in the props, I didn't get around to that. The props have inaccurate geometry of course, which I'm looking to fix with a mesher. Have a look at the console for how the geometric program is assembled.
- ade2 10y ago
  Cool. I think this tool has a lot of potential users, especially if you can make it pick between commonly available props, esc, motors and so on. Imagine how cool this would be if it could make a list of those things and export a 3d-printable frame :)

sheer_horror 10y ago

I managed to break the tool by inputting some infeasible inputs and then changing them again several times, and then refreshing the page.

lochieferrier 10y ago
This is my first time putting something up, everything is breaking, fixing it now.
- oneel 10y ago
  No test like a production test.

garyfirestorm 10y ago

That page is broken

Hydraulix989 10y ago
Slashdot Effect probs
- lochieferrier 10y ago
  Nope, I just have no idea what I'm doing.
  - duncan_bayne 10y ago
    hugs Takes some balls to go live with a project when you're on a step learning curve. Congrats :)
    - lochieferrier 10y ago
      Fixed it, didn't know about pythonpath with gunicorn.
  - huhtenberg 10y ago
    That will pass soon enough.

bnegreve 10y ago

Cool, I think more applications should be using solvers like this. What solver are you using? Is it solved server side?

lochieferrier 10y ago
Currently solved server side, though assembled on the client side (see console) with gpkitjs and then passed through to GPkit. Packages here: https://github.com/lochieferrier/gpkitjs https://github.com/lochieferrier/gpkitjs and here: https://github.com/hoburg/gpkit https://github.com/hoburg/gpkit Geometric programs are super cool.

frik 10y ago

It's called parametric modelling, and many CAD software use a parametric kernel (solver). https://en.wikipedia.org/wiki/Computer-aided_design https://en.wikipedia.org/wiki/Computer-aided_design Is this somehow different? Please explain

lochieferrier 10y ago
The difference is that there is a simple physics model that's driving the dimensions. So the arms are getting resized according to beam bending, the battery is a certain size for the energy requirement, motors are sized by kw/kg and kw/m^3 and so on. There's definitely ways to make this sort of model in something like Solidworks through the use of a variables interface that interacts with the drawing dimensions. Though it can't do any sort of fast optimization with the physics relations. What's happening here is a guaranteed global optimal design is being returned for a given set of inputs and objectives in a few seconds.
- veeedz 10y ago
  This sounds interesting but I can't react the site. Could you please explain how you get a guaranteed optimum? What if you have conflicting objectives?
  - lochieferrier 10y ago
    I think by react you meant react to, which was fair enough, it was dodgy as. Now running well. The property of getting a guaranteed optimum is something that arises from setting the design problem up as a geometric program. You won't always get a solution (for example, a certain size quad has a minimum prop diameter). Though if you do, it is guaranteed to be optimum because the problem is convex as outlined here: https://gpkit.readthedocs.io/en/latest/gp101.html https://gpkit.readthedocs.io/en/latest/gp101.html Also, conflicting objectives are naturally traded off until you find a Pareto optimal solution. Using geometric programs lets you balance conflicts in a design quickly. This is why they are super useful for aerospace applications, where you are always looking at a tradeoff between weight and at least one other variable.

doczoidberg 10y ago

this is more a configurator than a CAD.

kylestlb 10y ago

Nice project. What are you hoping to add in the future? Our team works on goal directed design as well, but at the moment it's less of an interactive optimization tool and more of an involved job running process a la Optistruct. One of our fun projects was a drone body as well :) link for the interested: https://autodeskresearch.com/projects/dreamcatcher https://autodeskresearch.com/projects/dreamcatcher

lochieferrier 10y ago
Wow, that is really beautiful. Topology optimization is cool stuff. I think it's key for optimization to be fast so that the designer can get a feedback loop going between the computer and the ideas in their head. Would love to talk about whether geometric programs might help Autodesk generate topology faster. Near future stuff is probably a real-world component input (optimized shopping), and making things more flexible so you can drag and drop something together from components.

diegoandrade 10y ago

This is not Physics-based at all, you need to introduce other variables like wind speed around the drone, the direction of the wind, angle of attack, viscosity, etc. This example is parametric modeling at best or a configurator, not saying that is bad, just has a misleading title. I do not see any real geometry manipulation or groundbreaking CAD being attempted. Here is a viewer that Autodesk released this year using javascript. https://developer.autodesk.com/ https://developer.autodesk.com/

lochieferrier 10y ago
For sure, there's a lot missing, title is probably misleading. Definitely nothing new in terms of the CAD, browser CAD has been well done, just look at professional products like Onshape. Right now it's primitives only for this, one of the next steps is to look at how full meshes can be optimized. A simple example of this could be wings: https://people.eecs.berkeley.edu/~pabbeel/papers/2013_gp_wind_turb.pdf https://people.eecs.berkeley.edu/~pabbeel/papers/2013_gp_win...