8 ms·

CAD Is a Lie: Generative Design to the Rescue

58 points by MichaelAO 11y ago

delish 11y ago
I'm interested in the future of CAD. Here's a link to implicitCAD[0], a constraint-solving CAD written in Haskell. There's interesting discussion; apparently what the author was trying to was proven by academic research to be Very Hard. Research he hadn't yet read! I've never done CAD, so I have nothing to contribute. I enjoyed the article! [0] https://news.ycombinator.com/item?id=9248174 https://news.ycombinator.com/item?id=9248174
- ddingus 11y ago
  Constraint solvers and geometry kernels are big, very expensive, beasts of software. They have grown over the decades, bit by bit, research yielding new approaches, as well as empirical, "Hey, I couldn't make this." use cases contributing to a very smart body of code with millions of man hours in it. Setting this tech aside, I would still classify CAD as an unsolved problem space. Even advanced kernels can and do fail, or generate erroneous geometry on what one would think is a common, or simple use case. That said, we are getting really good at basic geometry now. Those basic cases are much fewer and far between with most users just seeing robust operation now. It's taken many years for this to happen, marking time at the dawn of affordable solid modeling CAD in the mid 90's. Now, it's about getting computers to do what people can do, and that's infer intent as we do with our minds eye and analytic skill. It's also continuing to be about feature create, and that's all about how to boil down the UX of shape and intent description to the system. Also quite challenging. This kind of thing, as a branch in the "what's possible with CAD?" tree is pretty damn exciting! There are going to be a whole class of great use cases for this in the near future. Bear in mind, old feature create means and methods almost never die. They get sidelined, used less, whatever, but they continue to exist because there continue to be use cases they are excellent for. A lot of people think, "replace" when the real questions should be, "Add to, and what new things can we do?"
  - jpfr 11y ago
    Big systems growing over decades are usually easy targets for drastic simplifications by building upon better abstractions. There's a great talk by Alan Kay titled 'Is it really "Complex"? Or did we just make it "Complicated"?' [1]. He shows for example the Nile system where they replaced several 10k of vector-graphics rendering code with 450 lines. An example from a different context is the miniKanren / microKanren approach to logic programming. It's basically Prolog fitting on a single page [2]. If a similar simplification and unification could be accomplished for representations of (solid) 3D objects, that would be a great great result. [1] https://www.youtube.com/watch?v=ubaX1Smg6pY https://www.youtube.com/watch?v=ubaX1Smg6pY [2] http://minikanren.org/ http://minikanren.org/
    - ddingus 11y ago
      Over very long time periods, we may see progress here, but inertia is huge. Take Parasolid. It's a very good kernel. Between it, Granite and the Dassault kernel, we have most of the world's geometry being handled on those kernels. Probably billions of man hours at this point. Interoperability is basically terrible. If it were me, I would see efforts to interoperable and infer intent, features, etc... as the most productive task. Those kernels aren't going anywhere, nor are the geometry use cases getting easier. A refactoring of all that is a very seriously expensive, time consuming task and still that body of data, intent, automation, etc... is there to deal with. It's hard to even think about an economically viable case. There are some trying with primitive, open kernels, and various takes on forks of the established ones. One vendor is dividing the kernel into well defined pieces do that other software can operate in those gaps and do so efficiently.
  - brudgers 11y ago
    CAD will never be a solved problem space because ultimately it's the wrong problem space. The name of the blog shows why. The CAD problem space is an extension of "lines" as the design medium. It's implicitly premised on humans in the loop and creating human interpretible as a precursor to the artifact. There's an intermediate step that isn't strictly necessary and the CAD problem lives in that intermediate step. To put it another way, if I want a widget and I have the GCode and a 3D printer I'm pretty much done. I've bypassed the CAD space and more importantly it doesn't matter whether the GCode was generated via a DWG at some point or a computer program generated it directly without human intervention after searching through a million images from the internet. That kind of approach, however, is a problem for companies like Autodesk because without humans in the loop their product lines are obsolescent and Wall Street unhappy with management. The CAD industry depends on continuous rather than quantum change, because the obvious quantum change eliminates seats and with it per seat revenue models.
- grp 11y ago
  So you might be interested by the blog of Matt Keeter [1]. It's thesis is worth a read too [2]. [1] http://www.mattkeeter.com/projects/ http://www.mattkeeter.com/projects/ [2] http://www.mattkeeter.com/research/thesis.pdf http://www.mattkeeter.com/research/thesis.pdf
  - mkeeter 11y ago
    Hi! Most of my recent work has gone into a CAD tool called Antimony, with documentation at http://mattkeeter.com/projects/antimony http://mattkeeter.com/projects/antimony
    - grp 11y ago
      Yep! But I forget that one cause it is not exactly what I want.. (btw, I plan to contact you when I have finished a prototype).
ddingus 11y ago
Well yes and no. This tech is SUPER cool. It can find strength / weight combinations that are very difficult to arrive at via the standard analytic means. That's worth a lot in some contexts. However, these structures do not map well to existing manufacturing. They do map extremely well to additive manufacturing, of which ordinary 3D printing is a core component. CAD continues to segment: The very high end of CAD is serving the major vertical markets, and typically what happens there is tech like this will get licensed, reverse engineered, duplicated, whatever and integrated into a greater whole ecosystem that goes well beyond geometry create. Middle, or ordinary CAD, is being used for all sorts of stuff, and people don't mind a bit longer workflow, or missing out on some features. They want an effective tool at a great price, and their access to manufacturing tends to be as mainstream as the CAD is. On the low end, CAD is being used for maker / hobby tasks, and a whole lot of experimental type work. This tech is something to come out of that, and it's currently being supplied to the mid or mainstream CAD market by a vendor looking to move up and own more of the stack. Whether that's successful or not remains to be seen. There is a lot of legacy data, operations, systems that just can't be ripped out. Users of those systems may well adopt this feature in whatever system it's present in, and simply move the resulting geometry to the larger system, perhaps automate doing that too, and move on.
- DennisP 11y ago
  The article briefly touches on the manufacturing issue: "lets designers describe the forces that act on an object and then lets computers go off and make it. These forces can be structural loads or even manufacturing methods."
  - ddingus 11y ago
    It does, and not the scale of things, this is early, with really great advances to come. New manufacturing methods will help too. Additive is very well matched. I'm watching this closely. Additive, weaving, composites, nano scale, all are converging into a space that looks a lot more organic than what we do for the most part today.
- blacksmith_tb 11y ago
JeffreyKaine 11y ago
This, but for software UI/UX. Anyone want to put me out of a job?
- seivan 11y ago
  Do you write your UI to production or just define it in Photoshop?
  - JeffreyKaine 11y ago
    I "just" define it in sketch. To be clear, I'm sure you didn't mean to put down the role of design in building a successful software product, but I do like to point out unintended microaggressions when I see them.
    - seivan 11y ago
      My aggressions are neither micro nor ambiguous. I would never say design isn't important, seems counter-productive given that's what I (try to) spend most of my time on Oh sorry, second to "micro-aggressions".
- c54 11y ago
  We have some programming languages in which the programmer specifies a desired outcome, and the system figures out how to do it: Prolog and Haskell are two examples. We'll get there!
  - tome 11y ago
    Prolog satisfies that description much more closely than Haskell. In fact Haskell is really closer to C than Prolog, if that's the basis for the comparison.
    - YeGoblynQueenne 11y ago
      Prolog is probably the only language that gets even close to the original declarative programming promise, of giving the computer a goal and letting it find the way to achieve it. It looks like machine learning might be moving towards fulfilling that promise, btw. A bit of a shame that logic programming is not part of that. Prolog and machine learning would be a match made in heaven, if you ask me (you shouldn't, I'm biased).
modeless 11y ago
AIs may routinely design things in the future, but it'll be a while. Before that happens, people will be doing CAD in VR. VR is going to be a much bigger force for change in the CAD industry than AI for the next few years. I think anyone who has used an HTC Vive or Oculus Touch will agree that VR with tracked controllers is an order of magnitude improvement over monitor+mouse+keyboard for both viewing and creating three dimensional objects.
- mclau152 11y ago
  I'm curious how VR is going to be accessed for modelling in the near future (around Oculus release date), are there programs already in development for the big modelling softwares, or will they be standalone programs?
- mengen 11y ago
  I’m quite curious myself. Although, working at a place where we have 3D video walls with head tracking for quite some time you still can call me a sceptic. We only use them for presentations, the reason imo is that mechanical CAD modeling is really not just about creating 3D representations. An engineer works on math, tables (excel is big in engineering), enterprise resource management systems (you look up available material, prices, etc.), PIM software and of course the browser. You switch between them a lot. As far I can tell, the resolution of both Oculus and HTC Vive isn’t suited for editing larger texts or tables efficiently. Time (or better the VR industry) will solve this issue, but even then I’d argue many engineers prefer hand drawn sketches to support their thinking or for communicating ideas with their colleagues. While I’m sceptic concerning the use of VR for every day engineering, I believe it will be fantastic to let non-engineers explore designs. Like a production worker analyzing a design for assembly friendliness, where he can take apart the design without learning the right mouse-keyboard interactions or get used to a 3d motion controllers. Which, from my experience, is a huge barrier to them.
siscia 11y ago
I find the article a little off... The generative design it is showing has nothing to do with AI, it is just pretty advanced math, maybe with some heuristic, maybe not completely deterministic, but I would have an hard time calling it AI. Other than this, I enjoy the read.
- DennisP 11y ago
  The article doesn't mention AI.
  - siscia 11y ago
    This is a quote from the article: > "This is the computer becoming creative and able to generate ideas that people help to develop. Beyond creativity, the sea change is the computer’s ability to learn."
    - zardo 11y ago
      Then goes on to talk about how it would use machine learning to develop heuristic methods that could perform shallow design evaluations with much less computation.
samlittlewood 11y ago
Dreamcatcher sounds interesting - and in some sense, a return to older workflows. A friend worked at an F1 team at a point when they were transitioning from 2D draughting to parametric 3D CAD - One of the big issues was that in the prior setup, the designers would often draw bearing surfaces & forces on them, and the envelope - leaving the detail to the pattern makers. Whilst fast, this suffered from the varying skills of the pattern makers, and that they were all approaching or well past retirement age, with no prospect of new blood. The longer term benefits of the 3D CAD workflow took a while to realise, as it got mired in a lot of implementation detail that would previously have been deferred.
YeGoblynQueenne 11y ago
>> That white thing is a Frisbee, but it’s only a little line. How the heck did it know? There's a joke, it goes like this: A physicist, an engineer and a guru were asked what, in their opinion, is the greatest miracle in nature. The physicist said it was quantum entanglement. The engineer said he most admired the way human hands are articulated. The guru said "the thermos". Why the thermos, the guru was asked, of all things in nature? "It keeps warm things warm and cold things cold", the guru said. "That little bottle! How does it _know_?"
fsloth 11y ago
Note: This is an Autodesk blog marketing an Autodesk product. The funny thing is it leaves parametric modeling completely out of the discussion. That is, modeling based on pre-designed components that the end user then configures and lays out per the design intent. This amplifies the productivity of a person doing the modeling quite a bit. Granted, this works only in areas with fairly well understood problem and solution spaces and is a bit different than the approach described in the article. Just to point out it's not a review article in general, but a marketing piece.
- dsfsdfd 11y ago
  Yeah, but the vision of the article is bob on. This is how things are going to be (source: usually being right)
  - mhb 11y ago
    Of course it's right. But will it be right in 2 years or 25?
willyt 11y ago
Very interesting. It appears to generate a voroni mesh to resolve the structural forces. I can't tell from looking at this to what extent the overall shape is predefined by the requirements or generated by aerodynamic effects though. The next step would be for it to interpret concept sketches. Anyone who has worked for a design firm will know that most of the people there are interpreting and documenting the concept sketches of a few senior designers. They never write a detailed list of requirements as it's much quicker to sketch what you want to achieve and describe the sketches in conversation with your staff than to try and describe it in writing. Designers are visual people and hate having to write documentation. Clients write briefs, the brief for a skyscraper will probably stretch to a few thousand pages. But, as programmers will know too, you have to take some licence in interpreting them as they often contain a lot of contradictions.
brudgers 11y ago
Looking at the antennae, I'm unconvinced of the claim that the second is better [though I'm not saying it isn't] because it's not clear how suitable it is as a spacecraft component. The older design looks like it would be easier to store for liftoff (in a cylinder); require a simpler deployment strategy (a linear actuator); and be less likely to poke a hole in a spacesuit during extra vehicular activity. Not that I'm claiming it was for manned spacecraft. Yet that's the sort of corner case where it makes sense to lift an omnidirectional antenna. A point and shoot parabola is the general case. Parabolas fold and unfold well even when constructed from many parts because a lot of the parts are the same sku. The older design follows this idea by unfolding with a twist. The new antenna looks like it has more parts that are one off and looks like it depends on all of them deploying "just so" (i.e. it looks finicky). Again, the new design may actually be better. But without understanding the mission requirements, signal strength alone does not make the claim reasonable.
SixSigma 11y ago
As a CAD technician I was very aware that the purpose of a drawing was to communicate the requirements to the fabricator i.e. documentation.

58 points by MichaelAO 11y ago

I'm interested in the future of CAD. Here's a link to implicitCAD[0], a constraint-solving CAD written in Haskell. There's interesting discussion; apparently what the author was trying to was proven by academic research to be Very Hard. Research he hadn't yet read! I've never done CAD, so I have nothing to contribute. I enjoyed the article! [0] https://news.ycombinator.com/item?id=9248174 https://news.ycombinator.com/item?id=9248174

ddingus 11y ago
Constraint solvers and geometry kernels are big, very expensive, beasts of software. They have grown over the decades, bit by bit, research yielding new approaches, as well as empirical, "Hey, I couldn't make this." use cases contributing to a very smart body of code with millions of man hours in it. Setting this tech aside, I would still classify CAD as an unsolved problem space. Even advanced kernels can and do fail, or generate erroneous geometry on what one would think is a common, or simple use case. That said, we are getting really good at basic geometry now. Those basic cases are much fewer and far between with most users just seeing robust operation now. It's taken many years for this to happen, marking time at the dawn of affordable solid modeling CAD in the mid 90's. Now, it's about getting computers to do what people can do, and that's infer intent as we do with our minds eye and analytic skill. It's also continuing to be about feature create, and that's all about how to boil down the UX of shape and intent description to the system. Also quite challenging. This kind of thing, as a branch in the "what's possible with CAD?" tree is pretty damn exciting! There are going to be a whole class of great use cases for this in the near future. Bear in mind, old feature create means and methods almost never die. They get sidelined, used less, whatever, but they continue to exist because there continue to be use cases they are excellent for. A lot of people think, "replace" when the real questions should be, "Add to, and what new things can we do?"
- jpfr 11y ago
  Big systems growing over decades are usually easy targets for drastic simplifications by building upon better abstractions. There's a great talk by Alan Kay titled 'Is it really "Complex"? Or did we just make it "Complicated"?' [1]. He shows for example the Nile system where they replaced several 10k of vector-graphics rendering code with 450 lines. An example from a different context is the miniKanren / microKanren approach to logic programming. It's basically Prolog fitting on a single page [2]. If a similar simplification and unification could be accomplished for representations of (solid) 3D objects, that would be a great great result. [1] https://www.youtube.com/watch?v=ubaX1Smg6pY https://www.youtube.com/watch?v=ubaX1Smg6pY [2] http://minikanren.org/ http://minikanren.org/
  - ddingus 11y ago
    Over very long time periods, we may see progress here, but inertia is huge. Take Parasolid. It's a very good kernel. Between it, Granite and the Dassault kernel, we have most of the world's geometry being handled on those kernels. Probably billions of man hours at this point. Interoperability is basically terrible. If it were me, I would see efforts to interoperable and infer intent, features, etc... as the most productive task. Those kernels aren't going anywhere, nor are the geometry use cases getting easier. A refactoring of all that is a very seriously expensive, time consuming task and still that body of data, intent, automation, etc... is there to deal with. It's hard to even think about an economically viable case. There are some trying with primitive, open kernels, and various takes on forks of the established ones. One vendor is dividing the kernel into well defined pieces do that other software can operate in those gaps and do so efficiently.
- brudgers 11y ago
  CAD will never be a solved problem space because ultimately it's the wrong problem space. The name of the blog shows why. The CAD problem space is an extension of "lines" as the design medium. It's implicitly premised on humans in the loop and creating human interpretible as a precursor to the artifact. There's an intermediate step that isn't strictly necessary and the CAD problem lives in that intermediate step. To put it another way, if I want a widget and I have the GCode and a 3D printer I'm pretty much done. I've bypassed the CAD space and more importantly it doesn't matter whether the GCode was generated via a DWG at some point or a computer program generated it directly without human intervention after searching through a million images from the internet. That kind of approach, however, is a problem for companies like Autodesk because without humans in the loop their product lines are obsolescent and Wall Street unhappy with management. The CAD industry depends on continuous rather than quantum change, because the obvious quantum change eliminates seats and with it per seat revenue models.
grp 11y ago
So you might be interested by the blog of Matt Keeter [1]. It's thesis is worth a read too [2]. [1] http://www.mattkeeter.com/projects/ http://www.mattkeeter.com/projects/ [2] http://www.mattkeeter.com/research/thesis.pdf http://www.mattkeeter.com/research/thesis.pdf
- mkeeter 11y ago
  Hi! Most of my recent work has gone into a CAD tool called Antimony, with documentation at http://mattkeeter.com/projects/antimony http://mattkeeter.com/projects/antimony
  - grp 11y ago
    Yep! But I forget that one cause it is not exactly what I want.. (btw, I plan to contact you when I have finished a prototype).

ddingus 11y ago

Well yes and no. This tech is SUPER cool. It can find strength / weight combinations that are very difficult to arrive at via the standard analytic means. That's worth a lot in some contexts. However, these structures do not map well to existing manufacturing. They do map extremely well to additive manufacturing, of which ordinary 3D printing is a core component. CAD continues to segment: The very high end of CAD is serving the major vertical markets, and typically what happens there is tech like this will get licensed, reverse engineered, duplicated, whatever and integrated into a greater whole ecosystem that goes well beyond geometry create. Middle, or ordinary CAD, is being used for all sorts of stuff, and people don't mind a bit longer workflow, or missing out on some features. They want an effective tool at a great price, and their access to manufacturing tends to be as mainstream as the CAD is. On the low end, CAD is being used for maker / hobby tasks, and a whole lot of experimental type work. This tech is something to come out of that, and it's currently being supplied to the mid or mainstream CAD market by a vendor looking to move up and own more of the stack. Whether that's successful or not remains to be seen. There is a lot of legacy data, operations, systems that just can't be ripped out. Users of those systems may well adopt this feature in whatever system it's present in, and simply move the resulting geometry to the larger system, perhaps automate doing that too, and move on.

DennisP 11y ago
The article briefly touches on the manufacturing issue: "lets designers describe the forces that act on an object and then lets computers go off and make it. These forces can be structural loads or even manufacturing methods."
- ddingus 11y ago
  It does, and not the scale of things, this is early, with really great advances to come. New manufacturing methods will help too. Additive is very well matched. I'm watching this closely. Additive, weaving, composites, nano scale, all are converging into a space that looks a lot more organic than what we do for the most part today.
blacksmith_tb 11y ago

JeffreyKaine 11y ago

This, but for software UI/UX. Anyone want to put me out of a job?

seivan 11y ago
Do you write your UI to production or just define it in Photoshop?
- JeffreyKaine 11y ago
  I "just" define it in sketch. To be clear, I'm sure you didn't mean to put down the role of design in building a successful software product, but I do like to point out unintended microaggressions when I see them.
  - seivan 11y ago
    My aggressions are neither micro nor ambiguous. I would never say design isn't important, seems counter-productive given that's what I (try to) spend most of my time on Oh sorry, second to "micro-aggressions".
c54 11y ago
We have some programming languages in which the programmer specifies a desired outcome, and the system figures out how to do it: Prolog and Haskell are two examples. We'll get there!
- tome 11y ago
  Prolog satisfies that description much more closely than Haskell. In fact Haskell is really closer to C than Prolog, if that's the basis for the comparison.
  - YeGoblynQueenne 11y ago
    Prolog is probably the only language that gets even close to the original declarative programming promise, of giving the computer a goal and letting it find the way to achieve it. It looks like machine learning might be moving towards fulfilling that promise, btw. A bit of a shame that logic programming is not part of that. Prolog and machine learning would be a match made in heaven, if you ask me (you shouldn't, I'm biased).

modeless 11y ago

AIs may routinely design things in the future, but it'll be a while. Before that happens, people will be doing CAD in VR. VR is going to be a much bigger force for change in the CAD industry than AI for the next few years. I think anyone who has used an HTC Vive or Oculus Touch will agree that VR with tracked controllers is an order of magnitude improvement over monitor+mouse+keyboard for both viewing and creating three dimensional objects.

mclau152 11y ago
I'm curious how VR is going to be accessed for modelling in the near future (around Oculus release date), are there programs already in development for the big modelling softwares, or will they be standalone programs?
mengen 11y ago
I’m quite curious myself. Although, working at a place where we have 3D video walls with head tracking for quite some time you still can call me a sceptic. We only use them for presentations, the reason imo is that mechanical CAD modeling is really not just about creating 3D representations. An engineer works on math, tables (excel is big in engineering), enterprise resource management systems (you look up available material, prices, etc.), PIM software and of course the browser. You switch between them a lot. As far I can tell, the resolution of both Oculus and HTC Vive isn’t suited for editing larger texts or tables efficiently. Time (or better the VR industry) will solve this issue, but even then I’d argue many engineers prefer hand drawn sketches to support their thinking or for communicating ideas with their colleagues. While I’m sceptic concerning the use of VR for every day engineering, I believe it will be fantastic to let non-engineers explore designs. Like a production worker analyzing a design for assembly friendliness, where he can take apart the design without learning the right mouse-keyboard interactions or get used to a 3d motion controllers. Which, from my experience, is a huge barrier to them.

siscia 11y ago

I find the article a little off... The generative design it is showing has nothing to do with AI, it is just pretty advanced math, maybe with some heuristic, maybe not completely deterministic, but I would have an hard time calling it AI. Other than this, I enjoy the read.

DennisP 11y ago
The article doesn't mention AI.
- siscia 11y ago
  This is a quote from the article: > "This is the computer becoming creative and able to generate ideas that people help to develop. Beyond creativity, the sea change is the computer’s ability to learn."
  - zardo 11y ago
    Then goes on to talk about how it would use machine learning to develop heuristic methods that could perform shallow design evaluations with much less computation.

samlittlewood 11y ago

Dreamcatcher sounds interesting - and in some sense, a return to older workflows. A friend worked at an F1 team at a point when they were transitioning from 2D draughting to parametric 3D CAD - One of the big issues was that in the prior setup, the designers would often draw bearing surfaces & forces on them, and the envelope - leaving the detail to the pattern makers. Whilst fast, this suffered from the varying skills of the pattern makers, and that they were all approaching or well past retirement age, with no prospect of new blood. The longer term benefits of the 3D CAD workflow took a while to realise, as it got mired in a lot of implementation detail that would previously have been deferred.

YeGoblynQueenne 11y ago

>> That white thing is a Frisbee, but it’s only a little line. How the heck did it know? There's a joke, it goes like this: A physicist, an engineer and a guru were asked what, in their opinion, is the greatest miracle in nature. The physicist said it was quantum entanglement. The engineer said he most admired the way human hands are articulated. The guru said "the thermos". Why the thermos, the guru was asked, of all things in nature? "It keeps warm things warm and cold things cold", the guru said. "That little bottle! How does it _know_?"

fsloth 11y ago

Note: This is an Autodesk blog marketing an Autodesk product. The funny thing is it leaves parametric modeling completely out of the discussion. That is, modeling based on pre-designed components that the end user then configures and lays out per the design intent. This amplifies the productivity of a person doing the modeling quite a bit. Granted, this works only in areas with fairly well understood problem and solution spaces and is a bit different than the approach described in the article. Just to point out it's not a review article in general, but a marketing piece.

dsfsdfd 11y ago
Yeah, but the vision of the article is bob on. This is how things are going to be (source: usually being right)
- mhb 11y ago
  Of course it's right. But will it be right in 2 years or 25?

willyt 11y ago

Very interesting. It appears to generate a voroni mesh to resolve the structural forces. I can't tell from looking at this to what extent the overall shape is predefined by the requirements or generated by aerodynamic effects though. The next step would be for it to interpret concept sketches. Anyone who has worked for a design firm will know that most of the people there are interpreting and documenting the concept sketches of a few senior designers. They never write a detailed list of requirements as it's much quicker to sketch what you want to achieve and describe the sketches in conversation with your staff than to try and describe it in writing. Designers are visual people and hate having to write documentation. Clients write briefs, the brief for a skyscraper will probably stretch to a few thousand pages. But, as programmers will know too, you have to take some licence in interpreting them as they often contain a lot of contradictions.

brudgers 11y ago

Looking at the antennae, I'm unconvinced of the claim that the second is better [though I'm not saying it isn't] because it's not clear how suitable it is as a spacecraft component. The older design looks like it would be easier to store for liftoff (in a cylinder); require a simpler deployment strategy (a linear actuator); and be less likely to poke a hole in a spacesuit during extra vehicular activity. Not that I'm claiming it was for manned spacecraft. Yet that's the sort of corner case where it makes sense to lift an omnidirectional antenna. A point and shoot parabola is the general case. Parabolas fold and unfold well even when constructed from many parts because a lot of the parts are the same sku. The older design follows this idea by unfolding with a twist. The new antenna looks like it has more parts that are one off and looks like it depends on all of them deploying "just so" (i.e. it looks finicky). Again, the new design may actually be better. But without understanding the mission requirements, signal strength alone does not make the claim reasonable.

SixSigma 11y ago

As a CAD technician I was very aware that the purpose of a drawing was to communicate the requirements to the fabricator i.e. documentation.