Re^2: Confused about 3D geometry / algebra

I have been looking into 3D collision detection, but found that it mostly included using bounding boxes, which are not ideal for oddly shape molecules.

SVMs look very promising, as I only ever need to do the training case because I know which set my data points belong to.

As for data sets, they are merely several lists of the xyz coordinates of atoms in a molecule oriented in 3D.

        ...
44.886 -49.990 3.963
45.086 -50.645 1.973
45.120 -51.934 3.208
43.604 -51.123 2.800
        ...
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Re^3: Confused about 3D geometry / algebra by BrowserUk (Patriarch) on Jun 06, 2010 at 11:35 UTC
I have been looking into 3D collision detection, but found that it mostly included using bounding boxes, which are not ideal for oddly shape molecules. Yeah. Sorry about that. The only example I found, which you probably already saw, was more collision avoidance in footballing robots. And all the information I read on that was purely theoretical--no code available that I found. Indeed, pretty much everything I read about SVMs is that way; couched in terms and notations designed to impress peer review boards with little or no information or details on practical implementations. In general with computation geometry algorithms, if it's useful and can be made fast, then the game writers are your best reference for practical implementations. And understandable descriptions. Either they haven't caught on to SVMs yet, or haven't found a way to make them work quickly enough for their needs. However, don't be too ready to dismiss bounding. Calculating bounding spheres is well studied, and there are algorithms that give exact accuracy; or very fast approximations; or that can approximate fast and then refine incrementally to meet requirements. And the nice thing about bounding spheres is that they allow your determination to be made very quickly in many cases--bounding sphere don't intersect--and then allow you to focus on a tiny subset of the points within each groups--perhaps just 1 each--to make the determination when they do intersect. Regarding my request for a sample dataset--or preferably two sets; one with a clear separation plane and one without: it's just that it is an interesting problem (to me). And whilst I can generate test data for my explorations, it is always better to have real data. Invariably whatever you generate randomly omits some constraint or other that exists in the real problem space. If the datasets are too large to post I'd gladly fetch them or receive them some other way. I don't need any identifying data, just the points themselves? Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. "Science is about questioning the status quo. Questioning authority". In the absence of evidence, opinion is indistinguishable from prejudice. RIP an inspiration; A true Folk's Guy	[reply]
Re^4: Confused about 3D geometry / algebra by tomdbs98 (Beadle) on Jun 07, 2010 at 15:07 UTC
Ask and ye shall recieve, I chose 3 molecules, theres a picture of them here: http://imgur.com/BZVPA.png and the coordinate files are here: http://rapidshare.com/files/396314272/datasets.tar.gz Hopefully I didn't label anything wrong, I'm a little pressed for time this morning, but if anyone wants to have a look at these feel free :)	[reply]