Subject:
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Re: Utility Spreadsheet
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Newsgroups:
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lugnet.cad.dev
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Date:
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Thu, 15 Apr 1999 16:35:49 GMT
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Viewed:
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761 times
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On Thu, 15 Apr 1999 15:11:50 GMT, "John VanZwieten"
<john_vanzwieten@email.msn.com> wrote:
> Thanks a bunch for this. If I had a nickle for every time I've typed in
> formulas to interpolate a line . . .
No problem. I'm glad it was useful.
I had to make a formatted spreadsheet for my own use. Until I had this
thing, I would spend half an hour re-deriving the formulae, then typing it
in, then making corrections to what I typed. I'd do this every time I
needed to interpolate.
> I especially like the plane/line intersection sheet. I used it to compute the
> edge lines for right-angle intersection of two different sized cylinders,
> which has to be one of the worst things about part authoring.
Right angle intersection isn't so bad -- you already know one of your
target values, because it doesn't change. That reduces the problem to a
line intersection.
Also, you might look at the "Polyline Intersect" sheet. This layout would
help you find the interpolation of a line intersecting a polyline. Which
is a limited case of "I've got all these quads, no where does this line
intersect them?"
> Have you thought at all about computing the intersection of two quads?
Yep, that would be the next logical step.
> Lets
> see, if you could find the intersection of a quad and a line segment, then
> looking for each side of quad 1 intersecting quad 2 and each side of quad 2
> intersecting quad 1 should yield two points which would be the end points of
> the line segment of intersection. (I think). Well, if the quads were
> coplanar this wouldn't work, and a case where one of quad 1's sides lay on the
> plane of quad 2 would be a problem.
It also wouldn't work if the quads didn't intersect. :) But those cases
can be checked pretty easily.
> If such an intersection could be computed, then the intersection lines of two
> cylinders would be the sum of all intersections of the quads in cylindar 1
> with the quads of cylinder 2.
Right. But I think this would be a function that would work better if it
was embedded in LDAO (or some other program), because making a
user-friendly spreadsheet that would work with variable numbers of quads is
beyond me. And who would want a spreadsheet that only works to intersect
10 quads with 10 other quads?
But maybe I could write a VBA routine to assist with getting the data into
the sheet...
What I really want to do is to write a routine to project a set of quads
onto another set of quads. This could be useful for someone making minifig
faces -- they could create the face as a flat image-DAT, and project it
onto the 'surface' of the minifig head.
Steve
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Message has 1 Reply:
 | | Re: Utility Spreadsheet
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| In lugnet.cad.dev, Steve Bliss writes: <snip> (...) Well actually ..... I have done the specific case of minifig heads in Excel, but the code is currently a bit too experimental to share. It requires that the flat image-DAT has already been split at (...) (25 years ago, 15-Apr-99, to lugnet.cad.dev)
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Message is in Reply To:
| | Re: Utility Spreadsheet
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| Thanks a bunch for this. If I had a nickle for every time I've typed in formulas to interpolate a line . . . I especially like the plane/line intersection sheet. I used it to compute the edge lines for right-angle intersection of two different sized (...) (25 years ago, 15-Apr-99, to lugnet.cad.dev)
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