Wed, 16 May 2012 20:36:51 +0000 (GMT) -n brlcad <brl...@mac.com> írta:
> On May 16, 2012, at 04:08 PM, Csanyi Pal <csanyi...@gmail.com> wrote: > > How can I get a shape in BRL-CAD that has surface DERIVED somehow from > an Involute of a circle? > http://en.wikipedia.org/wiki/Involute > > http://en.wikipedia.org/wiki/Gear > Here is interesting the head: "Tooth profile". > > The gear example mentioned earlier at http://brlcad.org/tmp/gear has > teeth with an involute of parabola profile [1] [2]. If you check out > the gear.g geometry database also included there, you can see how I > did it for that specific example. I think I used a couple rpc's > intersected and subtraced by rcc's. Perhaps you can extend it for > your purpose, using intersecting right circular cylinders (rcc's) > instead of right parabolic cylinders (rpc's), or some other primitive > [3] if you really need them to be exactly circular. Well, I think it can't be done that way, because an involute of a circle is actually a spiral. In BRL-CAD is not such shape out there, right? But I find a webpage: http://www.cartertools.com/involute.html that describe how can one get an involute of a circle in a CAD application. On this link are .dxf files that I can easily open with LibreCAD. I imagine that that one could draw this way in BRL-CAD too a sketch, right? However, on my Debian GNU/Linux wheezy/sid I can't use neither in Mged nor in Archer the sketch function to draw circle. I can draw only lines. If I could draw such a sketch then I could extrude it to a cog, right? -- Regards from Pal ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ BRL-CAD Users mailing list brlcad-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/brlcad-users
