Tangent arcs, circles, or ellips
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I have used other CAD programs that allow you to draw circles that are tangent to one another.
I'm not seeing a function for that in LibreCAD, have I missed something?? Some of the "edit" functions available in the menu bar are not shown in the side pallet. Can they be added?? This program could be an important addition to my business, if I can get it to do what is needed I would be inclined to make donations (plural) to keep it up and running. You help me, I'll help you!!! LibreCAD is a fantastic start, I hope this works for us both. Allen |
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This post was updated on .
Allen,
Currently, I'm in charge of overseeing 2.0 series development, and I'm very interested in expanding geometry features of LibreCAD 2.0. I added several drawing methods for ellipse/cirlce to the 2.0 series already, and I'm eager to add the features requested. Before I start the implementation process, I would like to have the features well defined. Please let me know whether you would like to add anything to the following, 1, draw a circle tangential to a given circle/arc/ellipse by specifying the center of the new circle. drawing an arc can be done by drawing a circle first, and cut/trim the circle generated. 2, draw a circle tangential to a given circle/arc/ellipse by specifying two points on the circle. 3, draw an ellipse tangential to a given circle/arc/ellipse by specifying the ellipse center and two points on the ellipse. 4, draw an ellipse tangential to a given circle/arc/ellipse by specifying the ellipse center, major axis direction/radius. We don't have many developers available for testing, please help us by testing the new features in my own development branch ( https://github.com/dxli/LibreCAD ) before I merge them to the main tree. other features I was thinking about: to complete conic sections by adding drawing methods for hyperbola and parabola, since I'm not an engineer, I'm not sure whether those conic sections are useful in a CAD. Donations are always welcome. As a free software project: we care the most about the quality of our software, not market share or revenue generated. Thanks for reporting! dxli
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On 12-03-29 03:17 PM, dxli [via LibreCAD] wrote:
Allen,dxli, Thanks for your very kind reply. Any or all of the four drawing feature you mention are very useful. I do have one suggestion, the old version of MegaCAD had a drawing feature that was especially helpful. You could draw a tangent arc or line between two circles or ellipsis by clicking on the two entities, a tangent line would snap to both entities, and in the case of an arc, you would specifying a radius and providing your radius was large enough it would plot the arc tangentially to both entities, you could then trim and move on. It was also able to make tangent arcs (or circles) by clicking on three entities. This was all incredibly fast and effective! It would be great if you could make that happen! I'm glad to hear a conic section is forth coming, I have used those features in TuroCAD in the past and it would be a powerfull addition to LibreCAD. Having foci and directrix verifications as it applies to your drawings can be important information on some projects. Additionally, I was looking to see what file format's I could import, I found import to be unavailable. Will that be working in 2.0?? What format's will be on the list?? Approximately when is 2.0 going to be available?? Something you may want to keep in mind: If a person is running a Linux OS exclusively, you only have one other CAD program available to you that I know of worth anything (and I've looked). It's a program written by "Weber" and it is actually a CAM/CAD program with tool path generation and 3D solid modeling, all available at extra cost. It's way more program than most folks need or want and can cost up to $1200.00 US. An excellent value IF you need all that. Your commitment to a high end program first and foremost is commendable! I believe in what Linux and you folks are doing, especially as it pertains to third world users. They need technology they can afford or get their hands on so we can all benefit from our global intellect. Again, I will help fund your work as best I can if I can use it. I look foreword to hearing from you. Thank you again, Allen |
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This post was updated on .
In reply to this post by dxli
Hi Allen,
Here's the expanded list: 1, draw a circle tangential to a given circle/arc/ellipse by specifying the center of the new circle. 2, draw a circle tangential to a given circle/arc/ellipse by specifying two points on the circle. 3, draw an ellipse tangential to a given circle/arc/ellipse by specifying the ellipse center and two points on the ellipse. 4, draw an ellipse tangential to a given circle/arc/ellipse by specifying the ellipse center, major axis direction/radius. 5, draw a circle tangential to two given arcs/circles/ellipses by specifying the radius of the circle to be generated. 6, draw a circle tangential to two given arcs/circles/ellipses by specifying a point on the circle to be generated. 7, draw an ellipse tangential to two given arcs/circles/ellipses by specifying the major and minor radiuses. I'm not sure about the algorithm to do feature 7 yet, and also various complexity levels are involved for those features. I will start from the easier ones. Thanks, dxli |
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This post was updated on .
In reply to this post by Allen
implemented support for drawing a tangential circle of two circles, with the radius of the new tangential circle specified.
Please test this new feature in my repository: https://github.com/dxli/LibreCAD to do, add support for drawing a tangential circle of two ellipses need to enable arcs as well thanks, dxli |
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LibreCAD supports drawing a tangential circle of two entities of the types:
line/arc/circle |
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draw a tangential circle for three existing entities:
currently we have "draw circle inscribed", need to get combinations of: line/circle (arcs are treated as circles here, ellipse will be added after line/circle) One way to do it: find intersections between parabola and hyperbola. LibreCAD has its own quartic equation solver, so, this can be done by algebraic methods. I wonder whether there's an easier algorithm by approximate methods. dxli |
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In reply to this post by dxli
On 12-04-03 06:52 AM, dxli [via LibreCAD] wrote:
implemented support for drawing a tangential circle of two circles, with the radius of the new tangential circle specified.Hello dxli, Thank you for sending this update to try. I'm having trouble accessing it. When I try to install qt-4 SDK I get "command not found". I'm sure you have better things to do with your time than hold my hand on this, but if you can help me access this I will try to help by testing (or playing with it) for you, if not I may need to wait until it's available in 2.0. Thanks again |
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Hi Allen,
I suppose you are running Linux, and it's straight forward to install the newest development version of LibreCAD in Linux. Currently, debian, ubuntu, gentoo and archlinux all have native packages. Please follow our docs at: http://librecad.org/cms/home/installation/linux.html http://librecad.org/cms/home/from-source/linux.html For further assistance, talk to us on irc: #librecad at freenode.net, please be patient on irc: just ask your question, and keep the window open, if there's no one there to answer your question. I know Ries reads irc logs, and replies questions asked when he is off. For the next implementation, I am going to get "Problem of Apollonius", i.e., find a tangential circle of three given circles. This feature will be extended to include: find a tangential circle of two given circles and a given line; find a tangential circle of one given circle and two given lines; LibreCAD already supports drawing a tangential circle or three given lines. Thanks, dxli |
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On 12-04-05 07:33 AM, dxli [via LibreCAD] wrote:
Hi Allen,Hi dxli, Correct, I'm running Ubuntu 11.10. I got it installed and did a couple things with it. What a leap forword! I will try and make some time for it in the next few days and log any problems I may find. I'm anxious to use the features mentioned for the next step. This is good stuff. Thanks, Allen |
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In reply to this post by dxli
On 12-04-05 07:33 AM, dxli [via LibreCAD] wrote:
Hi Allen,dxli, One other thing! I lost the help files when I down loaded 2.0. I looked and could only find RC 2 for OSX and Windows. Any chance I could find and install those files from somewhere?? Allen |
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In reply to this post by dxli
On 12-04-03 04:30 PM, dxli [via LibreCAD] wrote:
draw a tangential circle for three existing entities:I don't know how much "easier" an algorithm by means of approximate methods would be, but, it's being useful to some users would depend on what kind of resolution they would have need of. One thing about absolutes is you can't go wrong. Allen |
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Implemented Appollonius's problem in master branch, commit:
4a3f76b..646b4b9 |
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Appollonius's problem is now supported, i.e., drawing a common tangential circle of three existing circles is now supported.
commit: 47754425b |
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On 12-04-08 10:38 AM, dxli [via LibreCAD] wrote:
Appollonius's problem is now supported, i.e., drawing a common tangential circle of three existing circles is now supported.dxli, I came across a problem: While drawing a tangent line from a five inch circle to a five inch circle (over lapping circles) the program shut down. It didn't save work or warn me in any way, it just shut down and went to my desk top. I will continue working and see how other improvements function. Thanks, Allen |
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In reply to this post by dxli
On 12-04-08 10:38 AM, dxli [via LibreCAD] wrote:
Appollonius's problem is now supported, i.e., drawing a common tangential circle of three existing circles is now supported.dxli, I was just doing some more tangent work (with good success) and as I was switching from circles to go back to draw a line the program went down again. I'm trying to find the trigger for this action. Any thoughts? Allen |
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In reply to this post by Allen
please file a bug report at our sourceforge bug tracker.
please include steps to reproduce the crash, and the version of librecad (1.0 or 2.0). all crashes by the stable version should be fixed at high priorities. thanks, dxli |
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Added to the master branch, a solver for general simultaneous quadratic equation sets of two. commit: https://github.com/LibreCAD/LibreCAD/commit/66eee790819e22362e7fd79bf64312fc93281217
LibreCAD already has a solver limited to handle ellipse related methods, while the newly added solver can handle general equation sets of (x, y) in the form of: ma000 x^2 + ma001 xy + ma011 y^2 + mb00 x + mb01 y + mc0 =0 ma100 x^2 + ma101 xy + ma111 y^2 + mb10 x + mb11 y + mc1 =0 The solver is based on algebraic methods relying on LibreCAD's own quartic equation solver. |
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