AutoCAD 2010/2011/2012

AutoCAD 2010/2011/2012

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Registered: ‎08-04-2011
Post 1 of 5

Parametric constrain /Tangent

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08-04-2011 02:43 AM


I'm worinkg with autocad 2012 full and am trying to figure out how to solve a parametric issue.

I would like to let a circle (in a 2d enviroment) to follow a path existing out of multiple arcs and lines. Is this possible?

I have managed to get this circle to follow only one arc but am not able to link it toany other segment in this particular path of multiple arcs and lines. Creating a polyline out of these segments does not give the solution. Autocad sees it as individual segments when attaching the parametric constrain.

In the attached drawing you will see a green coloured hook with a magenta outline at the bottom of it.

A "fix" constrain is set to the circle marked with a center mark, because this is the actual rotation point.

The goal is to let the magenta path (together with the complete hook) to follow the white circle when it's moved in a particular direction. The white circle should only be moved to the right on the X axis.

I have tried this with the "Tangent" constrain, but as I already mensioned the circle will correspond to only one segement of the magenta path.


I have posted this particular question also at the local resellers helpdesk, but they could not supply me with a solution.

Can you advise please?


Thanx in advance,

Sebastian Hougardy


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Post 2 of 5

Re: Parametric constrain /Tangent

08-04-2011 05:14 AM in reply to: SebastianHougardy8185

AutoCAD is not capable of dynamic motion simulation. Your problem involves time (where the white circle is at a given moment)  The circle can't be tangent to all the polyline entities simultaneously. AutoCAD's parametrics are static (Snapshot in time) see attached



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Post 3 of 5

Re: Parametric constrain /Tangent

08-04-2011 05:32 AM in reply to: LaserGuy

Thanx for your reply.

Unfortunately this does not help me any further in the design of this object.

Should I add this feature in the wishlist for Acad 2013? or buy other software wich can do the job...



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Post 4 of 5

Re: Parametric constrain /Tangent

04-04-2012 12:28 AM in reply to: SebastianHougardy8185

Hi Seb,


Sorry I have only replied to this issue only today, I just came across it while doing a google search.


Anyway, yep, AutoCAD's parametrics are quite limiting. There is however a product that is being developed for autocad which solves these problems and does more. It's called AGX, a powerfull parametric plugin which allows you to construct all sorts of parametric/associative geometry, and allows you to specify your own properties which allows dynamic adjustment of the properties of the associations.


Ie, you would be able to get your circle to 'follow' your complex 2d shape, made up of lines, arcs, splines, etc.


It is in testing stage, but the developer ( also needs people to test it for themselves, and this feature you require (if you still do) could be one for you to test.




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Post 5 of 5

Re: Parametric constrain /Tangent

04-04-2012 01:20 PM in reply to: SebastianHougardy8185

there is a real trick to it, but probably need to see in person to understand


Autodesk Inventor for a nmodern CAD tool designed for this functionality.



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