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Show HN: Physics-based CAD

prandtl.design

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Re: Show HN: Physics-based CAD

#21

Post by lochieferrier »

jamessb wrote: post #17
veeedz wrote: post #12

Earlier quoted context omitted.

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?

It forces you to assign a weight to each objective, converting from a multi-objective to a single-objective optimization problem (the weighted sum method). By varying the weights and re-running, you could identify a set a solutions on [convex regions of] the Pareto front.

This is correct, much better than what I said.

Re: Show HN: Physics-based CAD

#23

Post by hengheng »

lochieferrier wrote: post #9
frik wrote: post #7

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

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. Thou…

While this is well made, in production you would probably put the physics model in Excel with a bunch of VB scripting, and interface it to parameters and equations in solidworks. This isn't something I've done, but I absolutely wouldn't want to trade in a cad engine that can do everything badly just for some design tool that does a few things well.

if you want to get somewhere with this, you should consider the engineering work flow. usually there is a conceptual/design phase that consists of a lot of photographed whiteboards, physical mockups, Matlab, even Mathematica Notebooks if you're like that. Or actually, some cfd and multiphysics fem modelling if you are serious about your flying objects.

You seem to fit into this chaos sonewhere, but I wouldn't quite know at which point I should use this. After all, cad models are always parametric until you start adding all the details, and actual physics modelling even on a xflr5 level goes well beyond this.

Re: Show HN: Physics-based CAD

#24

Post by kylestlb »

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

Re: Show HN: Physics-based CAD

#25

Post by diegoandrade »

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/

Re: Show HN: Physics-based CAD

#26

Post by lochieferrier »

diegoandrade wrote: post #25

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…

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_win...

Re: Show HN: Physics-based CAD

#27

Post by lochieferrier »

kylestlb wrote: post #24

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

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.

Re: Show HN: Physics-based CAD

#28

Post by veeedz »

lochieferrier wrote: post #16
veeedz wrote: post #12

Earlier quoted context omitted.

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?

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: htt…

I meant to write reach, sorry. Glad that it's working well now. Thanks for the reply, and for the link, it sounds like something fun to get into =).
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