Full Version: Does Curve 3 points show Tangent mode?

Show messages:  1-17  18-37  38-57  58-62

Hi Psygorn,

re:
> So, in MOI 3D, when you already have a line how could you draw a curve tangent to that line, quick and fast?

Circle Diameter can make a circle tangent to a line quick and fast, the problem is that you want not just a tangent circle quick and fast but also passing through 2 points.

- Michael

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OK I believe i have found! :) Half only ! :( so...on the track!

And with my Apex trick! ;)

Just draw a little red arc circle 3 points! :)

Resists half to the big zoom! :)

Damned! It's good just on upper part! :(

https://moiscript.weebly.com/uploads/3/9/3/8/3938813/resist.3dm

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What a fight!
With a little red, a big black, intersection with the 2 Apex on the green Vertical
quasi perfect but...the black arc is not totally under the green one always on the bottom part at atomic zoom size! :(

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An another simple and quasi perfect but...

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Another one quasi perfect! But...
(crossing to perpendicular)

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Some geometric solutions at:
https://www.quora.com/How-do-you-construct-a-circle-passing-through-2-points-outside-line-L-and-tangent-to-line-L

- Michael

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Pilou -

I zoomed in to the microscopic level on my model and indeed it's not tangent. Then I tried the Jfs (PAQUICINNO) method in his video (which I think is the better solution), and it also was not tangent. Of course these are visual checks.

I don't know the mathematical solution, or even if displayed curves are 100% visually accurate when zoomed in that far.

Practically speaking, the error I saw when zoomed in that far is below the resolution on my micrometer :)

But it would be nice to verify what the precise solution is.

Update - I see Michael has linked to a solution above. Who wants to test it? :)

Ed Ferguson

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From https://www.quora.com/How-do-you-construct-a-circle-passing-through-2-points-outside-line-L-and-tangent-to-line-L?share=1

I think this one is the easiest:













Create circle/arc 3 pts through points A, B, P.

- Michael

Image Attachments:
tan_pt_pt1.jpg  tan_pt_pt2.jpg  tan_pt_pt3.jpg  tan_pt_pt4.jpg  tan_pt_pt5.jpg  tan_pt_pt_solution.png 

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Here's a video I made that demonstrates a reasonable way to make the tangent.
https://vimeo.com/545453177


Martin.

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Nice solution Martin!

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hi Martin

Nice vidéo; Very Clever !

Image Attachments:
BRAVO.png 

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Hi Ed,

I was suspicious about your solution. and yes I think PAQUICINNO's method works better maybe! ( yet it needs to be proved mathematically)

And I checked something when there is a line tangent to a circle and when you zoom in on atomic scale you see that there is a tiny gap between tangent line and the circle - which I believe it is normal to see such thing at such microscopic zooms - but there are no several crossings!

And feel free to check what I said in the attached file.

Attachments:
Tangent.3dm

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Thanks Martin :)

Your trick was genius!

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Hi Michael,

Could we expect to have such feature in Moi? Should I make a request for it in the wish list?

Note: Martin provided a simple trick which works! I know that. However, I still believe a built in feature would be nice!

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Hello guys, I have crossed upon new problem! You might be able to help :)

I tried to create Tangent curve to red line at Point_1 and the green circle.

( I know the center of the circle which is tangent to red line at Point_1 would fall on the Magenta line)

I was able to draw Blue curve using "Arc Tan" but it was by try and error method I have also tried to use Martin's method but in this problem because the blue curve should be tangent to red line at Point_1 I faced difficulties using Martin's method.

I'd appreciate any help :)

Attachments:
Tangent at point & Circle.3dm

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Hi Psygorn,

re:
> Could we expect to have such feature in Moi? Should I make a request for it in the wish list?

I'll see about adding it into the circle and arc tangent commands.

- Michael

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Tanx. :)

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So I have a problem with Martins video. Looking for some help.

I must be misinterpreting a click or a drag.

I make the line and 2 circles. Then offset the line the distance of circles.

Start the tangent circle command and select on first circle.

Second click on line ends command for me. It seems Martins video gets a second point click there, then third pick on second circle is a diameter pick for the tan snap...

What have I missed?

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Hi Burr, can you please post a .3dm file with your curves set up that isn't working as expected?

- Michael

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Here's the file

Attachments:
J_Screw_martin.3dm

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