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Subject: 
Re: Formalizing a method for handling synthesizable parts
Newsgroups: 
lugnet.cad.dev
Date: 
Sun, 6 Oct 2002 12:22:11 GMT
Viewed: 
698 times
  
Hi Philo,

In lugnet.cad.dev, Philippe Hurbain writes:
Hi Kevin,

It seems you forgot to link in CC3250.DLL... doesn't work on my system.

Oop.s  I reworked the organization of the code and ended up messing this up.
1.0.0.2 is uploaded now.


Boy, were you right, the triangle synthesis took a 3K file and made a 2M
file.  Unpalatable.

I switched lsynth over to use LDRAW parts for synthesis.  Now that 3K file
ends up to be 500K, still much larger, but certainly better than before.

That's the kind of size I got... We must keep in mind that even if the ldraw
file is smaller using parts, the number of triangle to render will be the
same or even higher :c(

I understand, but I'm not sure what can be done about this.  I used the
cross sectional parts that already existed for flexible hoses (76 and 77),
and created parts for the other diameter hoses, and cables, with the same
segment thickness.  I synthesize a hose between two constraints with a high
number of segments (oversampling?) and calculate the length.  I then divide
this by the length of a segment to get how many segments are needed.  Less
segments means that you can see gaps between the individual segments.

I'm not sure what we can do about the total number of triangles or quads.  I
suppose we could introduce more sets of hose cross sections that are longer.
Double the length, halve the number of quads.


The use of ldraw parts has an added benefit: it is more compatible with
LeoCad (with triangles you would have to create a new part and import it in
Leocad to be able to display something)

Bonus!


I've got most of the algorithms for rubber bands with pulleys/pins inside or
outside the bands as well as bands that have crossed over on themselves.  I
have not wandered through non-planar arrangements though.


I began to code crossed bands in my rubberbelt generator, but other project
kept me from finishing that. Note that crossed bands are not planar, there
is the thickness of the band to consider !

Yes. but that is easily dealt with.

I was referring to a pully being turned 90 degrees with respect to the other
pulley.

Thanks for all your input and help Pilo,

Kevin

http://www.users.qwest.net/kclague



Message has 1 Reply:
  Re: Formalizing a method for handling synthesizable parts
 
(...) Works fine now ;o) My tests were far from exhaustive though ! (...) I guess there is no perfect solution: modelling curved parts with some smoothness requires lots of polygons. Fortunately machine power increases! One possibility though would (...) (22 years ago, 6-Oct-02, to lugnet.cad.dev)

Message is in Reply To:
  Re: Formalizing a method for handling synthesizable parts
 
Hi Kevin, It seems you forgot to link in CC3250.DLL... doesn't work on my system. (...) That's the kind of size I got... We must keep in mind that even if the ldraw file is smaller using parts, the number of triangle to render will be the same or (...) (22 years ago, 6-Oct-02, to lugnet.cad.dev)

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