3 point arc
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Attach drawing files and screenshots.
Post one question per topic.
3 point arc
How can I draw a 3 point arc tangentially from an arc say.... on the left , down to a line and then tangentially to one on the right ? You can see (hopefully my previous attempt and you should see that the circle on the left is not tangential with the arc. All help gratefully received . Thank you .
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Re: 3 point arc
Your original photo (I've re-posted it as for me it didn't show up!):
Something like this?
Are you working to 'absolute' specific parameters for the arc ? (radius,start point coordinate etc...)
Something like this?
Are you working to 'absolute' specific parameters for the arc ? (radius,start point coordinate etc...)
Re: 3 point arc
If you look at my picture you will see a line atvthe bottom. The was another parallel to that. That is a restriction. I used 3 point arc but if you look close you will see it is not tangential to the left circle. I thought i might be able to snap tangentially , snap to object ( the line) and the tangentially to the right circle.
I hope i have explained that ok.
Thanks for the reply.
I hope i have explained that ok.
Thanks for the reply.
Re: 3 point arc
I'm still not sure I understand correctly - but does this help, what number (1, 2 or 3) do you want to snap to ?
Re: 3 point arc
Or do you mean like this ?
Re: 3 point arc
Thanks for being patient Clive . Maybe this might help you understand .
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Re: 3 point arc
Like this ?
Re: 3 point arc
Thats the badger......
Re: 3 point arc
Unfortunately that isn't possible in the moment - but I know that the developers are working on it for one of the next updates30tooo wrote:I thought i might be able to snap tangentially , snap to object ( the line) and the tangentially to the right circle.
Right now you have to work with construction / help lines to solve this challenge.
Re: 3 point arc
Okay - good, we got there in the end30tooo wrote:Thats the badger......
Well as Husky correctly points out the 'magic' button to do it all for you in QCAD is hopefully in development... and looking at the 'Bugtracker' - which is also used for submitting feature requests too - this seems to be the case:
http://www.qcad.org/bugtracker/index.ph ... ask_id=858
For me I often overlook the fact to mention that I use construction lines, circles and geometric principles to get the job done when I haven't got 'that particular' dedicated tool in QCAD to do it for me - thank you Husky for pointing that out .
Back to your question, basically I set up the circle tangents and the arc based on my sizes, what would be good is if you can post an example drawing with exact dimensions and positions of the circles and the 'restricting' line.
Regarding the arc - is the radius size important or does it just have to fit and look right ?
Regarding 'snapping' to the line - again does it just have to fit or snap to an exact coordinate point ?
Re: 3 point arc
@30tooo, Andrew has now released QCAD 3.2 and worked his magic and developed some exciting new additional circle tools - including one that will now accomplish what you are needing to do:
Point, 2 Tangents.
@Husky
Point, 2 Tangents.
@Husky
Hey Husky, looks like your feature request is now a reality - good news my friendHusky wrote:Unfortunately that isn't possible in the moment - but I know that the developers are working on it for one of the next updates
Re: 3 point arc
Yes, this should fit the bill.
BTW: The tool for this use case is called "3 Tangents" (not "Point, 2 Tangents"), I think the wrong tooltip might have been displayed in the screenshot above.
BTW: The tool for this use case is called "3 Tangents" (not "Point, 2 Tangents"), I think the wrong tooltip might have been displayed in the screenshot above.
Re: 3 point arc
Yes, The 'Point,2 tangents' should be the tool highlighted here - I accomplished an arc as needed by using 'Point,2 Tangents - not with the 3 Tangents!andrew wrote:BTW: The tool for this use case is called "3 Tangents" (not "Point, 2 Tangents"), I think the wrong tooltip might have been displayed in the screenshot above.
Re: 3 point arc
I see.. which point did you choose then? Is the exact point on the line given or another point? I thought the circle touches the two other circles as well as the line.
Re: 3 point arc
Well, it was just a quick test. Using the Point - 2 Tangents tool I followed the prompts and selected both circles first and then using 'Snap on entity' I then selected a point on the line - it wasn't a specific point!
But after further testing of these tools I find that I produce a result that stays tangent perfectly to the line using the '2 Points and Tangent' tool, of course first the 2 points need to be determined first on both circles, this is easily done by first placing two temporary construction lines from both centres at 60 and - 60 angles!
I think Apollonius 'The Great Geometer' would have loved these circle tools.
Andrew you have done a fantastic job with these additional tools
But after further testing of these tools I find that I produce a result that stays tangent perfectly to the line using the '2 Points and Tangent' tool, of course first the 2 points need to be determined first on both circles, this is easily done by first placing two temporary construction lines from both centres at 60 and - 60 angles!
I think Apollonius 'The Great Geometer' would have loved these circle tools.
Andrew you have done a fantastic job with these additional tools