I'm building a solution to fit a number of objects most efficiently into a box. I hope to implement more efficient algorithms soon, but to start out with I'm going to use the brute force method, checking every possible position. This is fine for now since the box is small, with a very few number of items. Later, the complexity will grow.
I'm using Unity to allow the user to see how the items ultimately fit in the box. My initial thought was to also use Unity's physics and collision detection to implement the best fit algorithm; but, with a huge potential number of locations and positions to check, is this a bad approach? Am I much better off running my algorithm in a data structure instead? A 10x10x10 box with even three 1x1x1 objects have almost a billion possible positions...
I'm new to Unity so any advice is welcome; thanks!
Update: right, so this problem is definitely in the bin-packing set of problems, which I know is NP hard. I'm assuming a rectangular box, filled with rectangular box-shaped items of random dimensions.
My question is...
My question is: given my particular algorithm, when we ask, "is there currently something in this x,y,z space?" would it be more efficient to figure that out via code, or to use Unity objects with collision-detection.
Based on the answers I've seen, I can see using Unity would be profoundly inefficient.
If you LITERALLY want to know:
"is there currently something in this x,y,z space?"
the best possible way to do that, is to simply use Unity's engine. So, you trivially check the AABB to see if a point is inside it (or perhaps just check for intersection). You can use one of many
I understand that the question "is there currently something in this x,y,z space?" is or could be one important part of whatever solution you are planning. And indeed the best way to do that is to let Unity's engine do that. It's absolutely impossible you or I could write anything as efficient -- to begin with it comes right off the quaternion cloud in the GPU.
That is the actual answer to what you have now stated is your specific question.
Now regarding the more general issue, which I first fully explained when that was the question you were asking :)
Here are some of my thoughts on trivial "box packing" algorithms in 2D, at the level useful in video games.
https://stackoverflow.com/a/35228592/294884
Regarding 3D "box packing" it's absolutely impossible to offer any guidance unless you include a screen shot of what you are trying to do and fully explain the shapes and constraints involved.
If you are a matheatician and looking for the latest in algorithmic thinking on the matter, just google something like "3d box packing algorithm"
example , example
Again, readers here have utterly no clue what shapes/etc you are dealing with, so please click Edit and explain!
Note too that sphere packing is a really fascinating scientific problem, if that's what you are talking about:
https://en.wikipedia.org/wiki/Close-packing_of_equal_spheres
Related
So, I’m attempting to create a 3d model of a bow (and arrow). I have some experience with making 3d models but nothing this complicated. I’ve created the 2d sketch of it and then extruded it to make it 3d, but I can’t figure out how to round the edges to make the bow circular rather than squarish. I’ve tried freeCAD, but the fillet causes the part to fail, and I’ve found no good alternatives that don’t cost me an arm and a leg.
Am I going about this totally wrong? Looking for some guidance or recommended references. Please excuse any ignorance on the topic I might be displaying here in asking this question.
This is a very broad question, and I would suggest first going over some tutorials like this to get started (in case you are interested in learning the software).
In case you just want the model for the bow and arrow, I'm positive you can find a whole bunch of them online (on sites like free3d.com or turbosquid etc.)
I recently got interested in Theo Jensen's strandbeest, (If you haven't seen them before look them up! Such incredible engineering.) and I want to mess around with the design he has for his strandbeests' legs. However doing straight forward kinematics is waaay over my head for something like this.
Here's what I'm trying to model:
https://upload.wikimedia.org/wikipedia/commons/6/61/Strandbeest-Walking-Animation.gif
(Can't link directly because I don't have enough reputation :/)
All I really need to know is the path of the 'foot', so something visual isn't necessary.
The final goal is to be able to apply an evolutionary algorithm to it and see if I come up with the same linkage lengths as Theo did, or maybe improve them somehow, so if I there was some software that allowed scripts to be run, that'd be ideal.
Sorry if the question is kind of vague, I'm not all that sure what I'm looking for. Even if there is some maths/engineering topic that would make this easier I'd love to learn.
Thanks!
-Oisin.
Well, I searched for Physics Engine, and found a promising result.
Open Dynamics Engine seems to be an open source physics engine that could fit your needs.
The Open Dynamics Engine (ODE) is a free, industrial quality library for simulating articulated rigid body dynamics. Proven applications include simulating ground vehicles, legged creatures, and moving objects in VR environments. It is fast, flexible and robust, and has built-in collision detection.
Source: Wiki Introduction
There site is ode.org, and it looks like you should be able to evaluate it from there. "[S]imulating rigid body dynamics" is what you want, right? From what I understand, it ought to fit the bill. C++ is probably a reasonable language to attempt this in. I presume you have previous programming experience? This is not what I would consider a beginner's project.
When you get to the evolution, search for Genetic Algorithms. They're frequently used for optimization, and could help you out considerably. Another thing to consider is what you're actually optimizing for (lowest wind speed to function, fasted movement, etc).
I m doing a research project on "Object detection using my a digital camera".
Some suggestion on how to build and program the Matlab code.
In particular, I have a picture of one object, say a screen of my laptop. Than I rotate the laptop and I shot a new picture. I would like to know the difference on the position of the screen. I think I can use the edge detection after a subtraction of the two images but... it is quite difficult for me to implement it.
Some suggestion on how to build and program the matlab code.
That largely depends on the goal you want to achieve. Can you be more specific? Are you streaming the frames or are you tracking offline?
In particular, i have a picture of one object, say a screen of my laptop. Than i rotate the laptop and i shot a new picture. I would like to know the difference on the position of the screen.
There are many ways to do this, and an extensive litterature on the subject. I don't believe anyone would write up the equivalent of a survey paper on the subject as an answer on StackOverflow. Why don't you get started with an object tracking survey paper and then ask a more precise question?
hi, I m doing a reasearch project on "Object detection using my a digital camera". [...] I think i can use the edge detection after a subtraction of the two images but...is quite difficult for me to implement it.
What is your question? Are you asking us if this is a good way to track objects? Are you asking us if this is a new approach and has never been done? Are you asking someone to implement it for you?
Object tracking is a hard problem. I doubt that technique would succeed in any but the most basic scenarios. However, if you look at a survey paper, you might be pointed to a paper that already implemented this an presents results. Finally, I think you should brush up your programming skills because most (successful) object tracking techniques are not trivial to implement. If you don't want to program it yourself, there are online services where you can hire people. StackOverflow is not one of those places.
EDIT: I could deduce that you're new to both programming (in MATLAB) and in object tracking, hence in my answer. Don't mis-understand me, I'm trying to help. Let me re-phrase my suggestions as list:
Your question is far too general. You will get a lot more help from the SO community if you ask more precise questions for two reasons: A) general question result in general answers; and B) the way you asked your question could easily be interpreted as "someone, please do my work for me" even if that's not what you think you're asking.
Get acquainted with the problem domain. To ask more precise questions, you must be close to your answer. For good knowledge on the "object detection and tracking", find a good survey paper. If you're starting off on a research project, people in your lab should be of help to point you to a good one.
Learn to program simple things first. All of the most proficient (effective and efficient) programmers I've ever met struggled with the bubble sort when they were introduced to sorting. None of them would have been able to program an object detection algorithm as a first assignment. Get yourself a good image processing book that has exercises in MATLAB, go through execises one by one. If you can't do them all, choose those that are relevant to what you're trying to accomplish.
I have a small UIImage (jpg) with a single typed number. I want to be able to read the number with some kind of pattern recognition. I'm really not sure where to start, so any help would be appreciated.
my initial idea was to compare this image with other images. For instance compare the image with that of a 1,2,3, etc until a match was found. That just seems slow and cumbersome and wondered if there was a better way to do it?
Thanks
Update - I'm trying to convert sudoku puzzles from newspaper print to interactive puzzles
No, you are right, it will be slow and cumbersome. But on the plus side you don't have to write it yourself
http://sourceforge.net/projects/opencvlibrary/
Still not exactly easy tho, and i'm not sure about licensing, so… you don't mention why you need to do this (sounds a little odd).
Maybe you can avoid it? If you know the images are numerical digits 0-9, is there another way to track which one a particalur images is, apart from the way it's pixels are arranged?
Sorry if that sounds like i'm missing the point… Maybe you could fill in a few more details?
I read this really good write-up about this exact problem here: http://sudokugrab.blogspot.com/2009/07/how-does-it-all-work.html
It doesn't have any code samples, but explains the concepts, and might be able to point you in the right direction.
The following tutorial may be right down your alley:
http://blog.damiles.com/2008/11/basic-ocr-in-opencv/
It is a simple tutorial on doing number recognition and comes with the source code also.
Additionally, you may want to do a search on OCR SDK (Optical Character Recognition Software Development Kit). You will surely find a stack of them. Commercial ones a pricey though.
I would go for a "role your own" approach along the line of the OpenCV tutorial, especially since you are only interested in numbers.
All of the best ':-)
I was looking at some study i have to do in the future to do with procedural generation techniques and i was wondering what type of content you have:
Developed
Helped Develop
Seen implemented
Tried to develop
and what methods/techniques/procedures you used to develop it.
If you feel generous maybe you can even go into specifics of it such as data structures ad algorithms you have used to develop it.
If this needs to be put as community wiki because it is not me asking for a problem to be solved just let me know.
This is not a homework thread because it is a research unit that i'm not taking yet ;)
Introversion software, the makers of the games Defcon, Uplink and Darwinia (among others) have started working on a game about a year ago which extensively uses PCG for city generation, here is a video of their work, and you can read more about it on the development diary of the game (start from the first part at the bottom of the page!).
This immediately got me extremely interested, and seeing the potential for games I immediately started researching the technology. I have amassed a folder of 18 PDFs about the subject (research papers, SIGGRAPH presentations, etc). Here, I uploaded it for you.
The main approach is to use L-Systems, however, I never got around to understanding enough of that to make something out of this. I tried other, less successful approaches like using Voronois, recursively splitting a rectangular area into more smaller areas and shifting the boundaries a little to obtain a bit of randomness and polygon division.
The last method I had gotten from Mike's Code Blog's posts (here and here). The screenshots shown on his blog make me drool, it is my biggest programmer's dream to ever get something that looks like that. I emailed him to ask how he did it, and here is the relevant part of his reply, I'm sure he wouldn't mind me posting this here:
L-Systems is definitely one way to go, but that isn't what I'm doing. The basis of my method is polygon subdivision. I start with a simple polygon that represents the entire area of the city. Then, I split it (roughly) in half, and then split those two polygons, etc. until I get down to city-block size. At that point, the edges of all my polygons represent roads. I then use the same subdivision method to break the blocks down into building-size lots.
The devil is in the details, of course, but that is the basic method.
I for one still haven't managed to fully implement a solution of which I'm satisfied of, but it remains one of, if not my single biggest programmer's dream to ever achieve something like this.
Here are a few of the leaders in procedurally generated terrain (and to a lesser extent foliage). If you don't get a detailed answer here regarding methods and techniques, you might want to look in / ask in their forums. I have seen some discussions of techniques there.
TerraGen 2
World Builder
World Machine
Natural Graphics
Noone mentioned the demoscene that ONLY use procedural stuff?
So, go search for Werkkzeug, Kkrieger, MilkyTracker to start. Also you can visit the site pouet and see the wonder of well done procedural videos (yes, procedural videoclips! With music and graphics, all procedural!)
Allegorithmic's products are used in actual shipping titles. These guys focus on texture generation (both offline and at runtime).
They have some very pretty screenshots and demos.