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I have created a circular curve and I'd like to add two points to it.

Enter image description here

I know I can select two points and then hit subdivide to get a new point in between these two points, but that is not a very efficient way to create extra points as it will change the shape of the circle. I then have to move them to position, which requires quite a bit of work of adjusting all the handles and move the point itself.

Is there a way to create the desired point by clicking on the circle so it won't change the shape of the circle?

I have tried installing the Curve Tools add-on as suggested, but I still can't find a way to make it work for this purpose.

Peter Mortensen
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hiro ober
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  • Perhaps the website which has a name that rhymes with noonoob has a tutorial on Curve Tools – atomicbezierslinger Dec 21 '20 at 04:52
  • There are a lot of super basic tools not present in Blender in version 1.0 (If that exsited) – atomicbezierslinger Dec 21 '20 at 04:59
  • OK, so I checked out the addon called Add Curves. It kinda works the way I wanted, but it still changes the shape of the circle after sliding out and placing the point in the specific position. – hiro ober Dec 21 '20 at 05:43
  • I have seen it work. Please see tutorial on youtube. Bisecting a bezier curve has been understood for probably 60+ years. You should think .. I need a tutorial .. rather than the tool cannot do this. Blender has a slide vertex ... for meshes which is quite convenient. I do NOT know if the tool has a slide ... curve point. – atomicbezierslinger Dec 21 '20 at 05:59
  • https://github.com/LeanderSilur/Blender-Tools/tree/master/curve_edit_tools#curve-edit-tools - I grabbed it from here. As shown in the gif, it works perfectly for Beizier curve. The newly added point keeps the shape of the curve. But not for the circle. It just changes its shape by adding a new point. – hiro ober Dec 21 '20 at 06:09
  • On the tool menu .. panel .. you may need to [Filter] and select your desired choice ... I just had some .. unexpected and not delicious experience – atomicbezierslinger Dec 21 '20 at 06:28
  • if you select all, press V, switch to Aligned and subdivide, it won't deform the shape, is it what you're looking for? (but you can't create an additional vertex wherever you want, this is a limitation of bezier curve, you need to first subdivide and then move, which does change the shape) – moonboots Dec 21 '20 at 09:37
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    @brockmann good find. – batFINGER Dec 21 '20 at 11:03

2 Answers2

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Set the handle type to Aligned

I should have read the question better, re subdividing, to have a new point remain on the circle to change the handle type.

Enter image description here

After adding the Bézier circle, select all in edit mode and Control Points → Set Handle Type → Aligned (Or only the two handles being sub'd.) The default Bézier curve has handle type 'AUTO' (look for a link to the handle type.)

After which the result of subdividing produces handles on the tangent.

Enter image description here

The active object is the default Bézier circle section subdivide, over the result above.

For a circle, after adding a point as above, can then "point slide" it in its two original handle quadrants by rotating about the circle center pivot point and adjust the handle points to make a sine, cosine ratio.

The left-to-right handle length will be constant. The alignment after rotate will be correct. To keep as a circle is a matter of sliding handles. For example, it would be all horizontal right handle if rotated back to the top, and all vertical left handle clockwise to right original point...

It is somewhat reminiscent of the position in a slot of How to do Trammel Of Archimedes Animation?

About to add the handle fix to How to rotate bezier control point (viewport not updating) ... However, for the answer to the question marked as a dupe has gone above and beyond - What is the fastest way to add vertices to a curve at a specific point?

Peter Mortensen
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batFINGER
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Curve Tools is addon . Menu Edit/User preferences. You can search by text and click the enable checkbox. Blender 2.91

enter image description here

Subdivide and Multisubdivide are depicted above.

enter image description here

You may need to use the filter panel depicted above.

atomicbezierslinger
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  • Thank you so much guys! I turned on Curve Tools under Addon tab but it doesn't seem to work at all as when I shift A under curve menu, I don't see a bunch of new curve objects in the menu. Don't know what's going wrong here. What's the common reason for an addon not showing up? – hiro ober Dec 21 '20 at 05:14
  • Press the N or T keys to see panels open up. Be in [] mode. I am one person .. so maybe I am one guy .. American English .. maybe Dude .. Bloke? ... Perhaps the website which has a name that rhymes with noonoob with lots of videos .... has a tutorial on Curve Tools – atomicbezierslinger Dec 21 '20 at 05:29
  • Sorry, I thought I'm replying to all the above posts including yours...Haven't got used to the structure of stackexchange. Yes I'm pretty sure I'm in edit mode. By toggling N and T, I don't see Curve tools showing up anywhere. I'll dig into why it wasn't activated even I turned it on already. Thank you for pointing me in the right direction! – hiro ober Dec 21 '20 at 05:36
  • Yeah I've got other addons turned on without a problem, but weirdly this Curve Tools simply doesn't work. According to what I see on several YTB tuts, I should have a bunch of new curve shapes available under the Curve menu when pressing shift A. Nope, still the same old 5 options. – hiro ober Dec 21 '20 at 06:13
  • @hiroober ... please see edit – atomicbezierslinger Dec 21 '20 at 06:32
  • I really appreciate your help. I did it, but still no Curve Tools. Please see my screengrab in the edit above. – hiro ober Dec 21 '20 at 06:50
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    @hiroober Go into Edit Mode and in the N menu panel on the right go to Edit, there are some extra tools appearing when you enabled Curve Tools. When they are there, if you want to make sure that the shape of the circle is preserved you should use Multi Subdivide even if you only want a single subdivision and enter a value your liking. This way the shape is (mostly) preserved. – Gordon Brinkmann Dec 21 '20 at 07:09
  • Thank you so much! I got the Multi Subdivide working though I still don't have more options under Curve menu...Googling around now. – hiro ober Dec 21 '20 at 08:11
  • @hiroober If you feel I have answered the question please mark it as the answer. You can also mark the question with negative points if you like. – atomicbezierslinger Dec 21 '20 at 16:29