Subject:
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Re: On the difficulty of making building instructions
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Newsgroups:
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lugnet.cad
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Date:
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Wed, 7 Feb 2001 20:43:58 GMT
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Viewed:
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869 times
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In lugnet.cad, Don Heyse writes:
> In lugnet.cad, Jacob Sparre Andersen writes:
> > On the difficulty of making building instructions:
> >
> > Last sunday I spent most of the day (except for a few hours out
> > in the snow) showing my cousins how to make - or should I say
> > _draw_ - building instructions on a computer.
> >
> > Personally I use vi+ldglite for this (yes, I know I should swap
> > vi for Emacs), but that is not really an option for kids who
> > haven't learned to do three dimensional geometry, matrices,
> > vectors and all that.
> >
> > We - or rather they - also tried with MLCAD, and even though
> > they practically could compete with me in speed, the quality
> > (mostly lack of alignment) gave them some problems.
> >
> > This lead me to lie sleepless most of the night trying to
> > figure out how to solve this problem. So far I have come to the
> > conclusion that our problem is that we attempt to _draw_
> > instead of _build_ - we move the parts around until the drawing
> > looks right, whereas we with the real thing have the benefit of
> > connecting the parts to each other.
> >
> >
> > I will see if I can get any further with this, when I have a
> > bit more time (read: when I have handed in my PhD thesis).
Your Phd thesis is not about 3D CAD interfaces then I take it?
(Which incidentally is an area of Computing Research if you know WHERE to
look and ask..)
> BlockCad (and perhaps other programs) does some collision detection
> when moving the bricks to assist in the placement. You could enhance
> this by inventing a mouse that provides some tactile feedback (ala
> playstation controllers) when the bricks bump into each other.
> Audible feedback may work just as well. A small click for a bump in
> one direction, louder for two directions. Stereo effects?
This sounds like a good technique... Audible feedback.. However my qyery is
how easy woudl it be to add this in s/w? You would also need to have some
system for determing bounding boxes. (ISTR GL doing this? I'm pretty sure
SERIOUS UNIX graphic libs (Like PHIGS) have C functions for it..)
> Back when I worked in a certain 2D CAD industry we used a simple
> mechanism that allowed the user to propel an object along a 2D vector
> until it hit another object. At that point it would either stop or
> continue moving along a different vector as long as the dot product of
> the new and original vectors was positive. Various options could be
> applied to this motion such as stopping at the first point of contact,
> wiggling a bit for a better fit, or snapping to a grid (think stud
> spacing).
Hmm, you've given me an idea for a non L-CAD project... (Unless of course
the technology is under patent...)
> Unfortunately I have no idea as yet how to easily generate
> a 3D vector (rather than a 2D vector) to propel a brick along.
> Perhaps with a spaceball instead of a mouse?
Incidentaly a 3D grid interface for doing drawing was something I looked
into for my college project.. City University should have a library copy of
my project report. (I can't remember the URL of the archived Word version at
the moment... :-( )
> Once upon a time I daydreamed about trying out some of this stuff with
> the leocad source, but I also have a problem with available free time.
Always a problem free time ;-)
Alex
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Message is in Reply To:
 | | Re: On the difficulty of making building instructions
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| (...) BlockCad (and perhaps other programs) does some collision detection when moving the bricks to assist in the placement. You could enhance this by inventing a mouse that provides some tactile feedback (ala playstation controllers) when the (...) (24 years ago, 7-Feb-01, to lugnet.cad)
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