4 ms·

Somehow it seems less polished of a command line tool that way, but it was perfect for my needs. I actually ran it over night to pack a model of a deer, packing

Somehow it seems less polished of a command line tool that way, but it was perfect for my needs. I actually ran it over night to pack a model of a deer, packing 8 of them together. It produced this histogram of scores: http://i.imgur.com/VENTeIa.png http://i.imgur.com/VENTeIa.png So it could easily find arrangements that scored around 65% while the best it found was like 52% (lower is better and basically anything under 100% is better than naive packing).

fogleman 9y ago
Here are the 8 deer by the way: http://i.imgur.com/RDwzbD8.png http://i.imgur.com/RDwzbD8.png
- deleted 9y ago
  [deleted]
sitkack 9y ago
I could see other heuristics for termination Delta improvement / delta time X minutes or y percentage Does it parallelize?
- fogleman 9y ago
  In general, simulated annealing is hard to parallelize. But in this case we also tend to get stuck in local minima a lot, because they are very deep troughs in the search space. (Annealing does still perform much better than hill climbing though, so it's still worthwhile.) So we can run multiple annealings in parallel and pick the best result.
  - sitkack 9y ago
    How about tossing a bunch of boats into the build volume and shaking it? Use a sand/particle simulation to fit them together, seems amenable to the GPU.
    - vortico 9y ago
      If passing through one another is allowed during the physical simulation, this is just a CPU-heavy simulated annealing. If not, you won't reach solutions that are "far away" from your initial condition in terms of number of passes required to reach it.
  - sitkack 9y ago
    The process could be made continuous by building in supports to the volume of parts being printed, so it wouldn't need to be supported from the bottom for the whole duration of the build. Continuous Selective Laser Sintering via periodic support structures and powder dams. The interlocking parts and periodic build support structures could be made so that eventually lower parts could fall away and the powder recycled. One could also build in dams, so that the powder didn't fall away as the lower parts fell away. Those dams would allow for powder retention.
  - sitkack 9y ago
    In parallelization of annealing, do you think it would be worthwhile to broadcast the paths that are A) already taken B) not productive ? So that, each parallel annealer is working in a unique solution space?

fogleman 9y ago

Here are the 8 deer by the way: http://i.imgur.com/RDwzbD8.png http://i.imgur.com/RDwzbD8.png

deleted 9y ago
[deleted]

sitkack 9y ago

I could see other heuristics for termination Delta improvement / delta time X minutes or y percentage Does it parallelize?

fogleman 9y ago
In general, simulated annealing is hard to parallelize. But in this case we also tend to get stuck in local minima a lot, because they are very deep troughs in the search space. (Annealing does still perform much better than hill climbing though, so it's still worthwhile.) So we can run multiple annealings in parallel and pick the best result.
- sitkack 9y ago
  How about tossing a bunch of boats into the build volume and shaking it? Use a sand/particle simulation to fit them together, seems amenable to the GPU.
  - vortico 9y ago
    If passing through one another is allowed during the physical simulation, this is just a CPU-heavy simulated annealing. If not, you won't reach solutions that are "far away" from your initial condition in terms of number of passes required to reach it.
- sitkack 9y ago
  The process could be made continuous by building in supports to the volume of parts being printed, so it wouldn't need to be supported from the bottom for the whole duration of the build. Continuous Selective Laser Sintering via periodic support structures and powder dams. The interlocking parts and periodic build support structures could be made so that eventually lower parts could fall away and the powder recycled. One could also build in dams, so that the powder didn't fall away as the lower parts fell away. Those dams would allow for powder retention.
- sitkack 9y ago
  In parallelization of annealing, do you think it would be worthwhile to broadcast the paths that are A) already taken B) not productive ? So that, each parallel annealer is working in a unique solution space?