MIT Courseware Linear Agebra with videos http://ocw.mit.edu/courses/mathematics/18-06-linear-algebra-spring-2010/
On Thu, Aug 15, 2013 at 1:51 PM, Matt Lind <ml...@carbinestudios.com> wrote: > Tell me, Gray – what is a ‘true’ vector? I’ve never heard of that term. > ;-)**** > > ** ** > > As for the textbooks, I only recommend the Gerald Farin book for the same > reason as you – the textbook I used in college was awful. Awful enough I > purchased 5 different linear algebra textbooks to figure it all out as most > come with the same 8 topics, but only explain 2 or 3 of them well, and > rarely come with examples directly applicable to what we do here.**** > > ** ** > > The Farin book complements a traditional linear algebra course by > illustrating the subset of concepts applicable to the case of working in 2D > or 3D computer graphics. If you have a linear algebra background, you’ll > breeze through the book pretty fast. However for somebody getting their > feet wet in the subject, it’s really good for introducing concepts and > guiding the reader on the right track for pursuit of further knowledge. > Hindsight being 20/20, I would be more interested to learn the subject if I > had the Farin book before my college textbook.**** > > ** ** > > The Farin book, by the way, is a reworking and simplification of his > previous book whose name escapes me at the moment, but is based on linear > algebra for CAD and CG co-written with Dianne Hansford.**** > > ** ** > > ** ** > > Matt**** > > ** ** > > ** ** > > ** ** > > ** ** > > ** ** > > ** ** > > *From:* softimage-boun...@listproc.autodesk.com [mailto: > softimage-boun...@listproc.autodesk.com] *On Behalf Of *Grahame Fuller > *Sent:* Thursday, August 15, 2013 9:18 AM > > *To:* softimage@listproc.autodesk.com > *Subject:* RE: just not normal**** > > ** ** > > Joey,**** > > ** ** > > ICE doesn’t convert locations directly. It can display them as vectors for > debugging purposes but under the hood they are really a triangle ID + > barycentric coordinates. Or perhaps you meant true vectors?**** > > ** ** > > The list of attributes that ICE will convert to the self’s reference frame > is here: > http://download.autodesk.com/global/docs/softimage2014/en_us/userguide/index.html?url=files/ICE_trees_GettingandSettingDatainICETrees.htm,topicNumber=d30e274098(scroll > down to “Reference Frames”, right before “Setting Data”). You can > trust ICE to use the correct math, 3x3 or 4x4 matrices, depending on > whether the attribute is a true vector or position, but if it’s a custom > attribute then it’s up to you to know what it is and take the appropriate > action. **** > > ** ** > > The book that Matt mentioned looks interesting as an intuitive, > geometrical approach. For a more technically oriented book I’d recommend > Shilov’s “Linear Algebra” — when I was at uni the assigned textbook was > awful but Shilov’s just clicked with me.**** > > ** ** > > gray**** > > ** ** > > ** ** > > *From:* softimage-boun...@listproc.autodesk.com [ > mailto:softimage-boun...@listproc.autodesk.com<softimage-boun...@listproc.autodesk.com>] > *On Behalf Of *Matt Lind > *Sent:* Wednesday, August 14, 2013 7:52 PM > *To:* softimage@listproc.autodesk.com > *Subject:* RE: just not normal**** > > ** ** > > It will differentiate how to handle orientation vectors differently from > position vectors which is the solution to the problem you said you couldn’t > solve on your own.**** > > ** ** > > Matt**** > > ** ** > > ** ** > > ** ** > > *From:* softimage-boun...@listproc.autodesk.com [ > mailto:softimage-boun...@listproc.autodesk.com<softimage-boun...@listproc.autodesk.com>] > *On Behalf Of *Ponthieux, Joseph G. (LARC-E1A)[LITES] > > *Sent:* Wednesday, August 14, 2013 4:49 PM > *To:* softimage@listproc.autodesk.com > *Subject:* RE: just not normal**** > > ** ** > > I’m certain that it would be very useful, but what I am more interested in > is what ICE is pre-computing that changes what might be normal expectations > such as the example provided with locations. With ICE, positions are > converted to global using 4x4 matrices and locations are converted to > global using 3x3 matrices. Will a linear algebra book be able to tell me > that, in context to ICE?**** > > ** ** > > --**** > > Joey Ponthieux**** > > LaRC Information Technology Enhanced Services (LITES)**** > > Mymic Technical Services**** > > NASA Langley Research Center**** > > __________________________________________________**** > > Opinions stated here-in are strictly those of the author and do not **** > > represent the opinions of NASA or any other party.**** > > ** ** > > *From:* softimage-boun...@listproc.autodesk.com [ > mailto:softimage-boun...@listproc.autodesk.com<softimage-boun...@listproc.autodesk.com>] > *On Behalf Of *Matt Lind > > *Sent:* Wednesday, August 14, 2013 7:39 PM > *To:* softimage@listproc.autodesk.com > *Subject:* RE: just not normal**** > > ** ** > > The documentation you’re searching for is a linear algebra textbook. I > think you’ll find the subject very useful and directly applicable to your > work on many fronts. “Practical Linear Algebra: A Geometry Toolbox” by > Gerald Farin is a decent starting point as it discusses the fundamentals in > plain english, but it’s intended to complement a linear algebra course, not > replace it.**** > > ** ** > > ** ** > > Matt**** > > ** ** > > ** ** > > *From:* softimage-boun...@listproc.autodesk.com [ > mailto:softimage-boun...@listproc.autodesk.com<softimage-boun...@listproc.autodesk.com>] > *On Behalf Of *Ponthieux, Joseph G. (LARC-E1A)[LITES] > > *Sent:* Wednesday, August 14, 2013 4:23 PM > *To:* softimage@listproc.autodesk.com > *Subject:* RE: just not normal**** > > ** ** > > WOW! What a difference two nodes make! I converted the 4x4 Matrix down to > a 3x3 Matrix omitting Translation in the process, and plugged that into > Multiply Vector by Matrix and…EVERYTHING WORKS!**** > > ** ** > > The flipping is gone. **** > > ** ** > > I had solved the problem by taking three points on the surface, converting > to global position on each, then deriving a “normal” vector from them. It > was rock solid and this solution has the same results as that. My > preference was to get the normal from the location, that way if the object > surface is irregular it will always work as expected. This solves that > problem very elegantly!**** > > ** ** > > I’m curious, but is there any documentation anywhere that gives better > detail on how locations vs positions etc affect global space conversion? I > would have never guessed how to solve this even though I knew about the > local to global conversion from the docs.**** > > ** ** > > Thanks!**** > > ** ** > > --**** > > Joey Ponthieux**** > > LaRC Information Technology Enhanced Services (LITES)**** > > Mymic Technical Services**** > > NASA Langley Research Center**** > > __________________________________________________**** > > Opinions stated here-in are strictly those of the author and do not **** > > represent the opinions of NASA or any other party.**** > > ** ** >
