Subject:
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Re: Use of arbitrary elements with LSynth
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Newsgroups:
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lugnet.cad.dev
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Date:
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Tue, 15 Feb 2005 23:55:00 GMT
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Viewed:
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2317 times
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In lugnet.cad.dev, Larry Pieniazek wrote:
> Kevin
>
> I've created an element that represents a small segment of string. It's not
> a real, legitimate LDraw part, per se, but I find it useful in my modeling.
>
> Is it possible to get LSynth to use this element? I'm looking for it to be
> treated similar to a rubber band in that I may want it to be (partly) wound
> around constraining things like bushings or pulleys, but similarly to a flex
> tubing in that it will usually be open ended.
>
> Usually I would want it to be taut, with all segments tangent except where
> wound around a constraint, but sometimes not taut (for example if shown
> coiled out of the way)
>
> I read the instructions for LSynth and I even have a copy of your book, like
> the instructions suggest (grin), but I didn't see this topic covered in the
> LSynth chapter.
>
> For reference, here's the string segment model I use. This segment is NOT
> very accurately modeling a 3 strand twisted string but it has enough non
> black in it from a distance to sort of give the impression of highlights. I
> abut two of these, one rotated 180 degrees so the triangles face the other
> way, to give a diamond reflective effect.
>
> You can see my use of string in the POV render at the top of this page
> http://www.miltontrainworks.com/item_info_1004.html#MTW-1004-by
> as well as in the instructions fragment partway down the page. At these
> magnifications it is good enough. All the string segments were pieced
> together by hand, including transitions from tangent to curved around
> bushings and so forth.
>
> A generic way to use LSynth would be very welcome!
Hi all,
I have rewritten much of LSynth's code so that it is table driven. Currently
the tables are coded in the program, but the important thing is that definitions
of synthesized things are tabular.
I've added a string type that uses your string segment, Larry. It synthesized
as a tube made out of fixed size segments, just like ribbed and rubber hose. I
don't have support for string with slack pulled down by gravity. Sorry.
I've modified pneumatic hose, electric cable, flex system hoses, flex system
cables, flexible axles and fiber optic cable are synthesized with parts that are
scaled in length. I provide a parameter that lets you define the angular
resolution.
LSynth synthesizes the curve between any two constraints. LSynth starts at
the first segment, and compares the angle between the first segment and the
second segment. If the angle between the two segments are lower than the
angular rsolution, then the two segments are merged.
The effect is that high curvature requires a log of short segments, but long
straight stretches just takes a single segment. This has a dramatic effect on
file size reduction. Also modified code to only put out part usage lines with
only to decimal places. Synthesized files are much smaller.
As soon as I remember how I'll put this back on sourceforge, and do a release.
I also fixed the spacing associated ribbed hose. I also fixed issues with
ribbed hose, rubber hose, string specified with more than two constraints. Now
the boundaries between constraints are seemless on these tubes composed of fixed
lengths.
I did some minor fixing in the rubber band/chain area too. I made it tabular
as well. I fixed some issues with boundaries between curves and tangent lines
(sometimes they didn't meet). For rubber bands, the tangent lines between
pulleys are one long piece, conserving on file size.
Where possible in all of the above, I used primitives or S parts, instead of
using parts created and used by LSynth in the past.
I need to give Willy's tutorial page again to make sure to address the issues
he raised there.
There is still the issue of LDraw parts used by LSynth that are not officially
parts of anything. Maybe they should be put in parts/s directory.
Chris, Orion, feedback on this last part?
Kevin
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Message has 1 Reply:
 | | Re: Use of arbitrary elements with LSynth
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| (...) Kevin- Is this enhanced LSynth program available for download anywhere yet? All I can find so far is 2.0 on your web site here (URL) I'm looking forward to things like string! -Matt :) (19 years ago, 28-Sep-05, to lugnet.cad.dev)
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Message is in Reply To:
| | Use of arbitrary elements with LSynth [DAT]
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| Kevin I've created an element that represents a small segment of string. It's not a real, legitimate LDraw part, per se, but I find it useful in my modeling. Is it possible to get LSynth to use this element? I'm looking for it to be treated similar (...) (21 years ago, 22-Apr-03, to lugnet.cad.dev)
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