topic Cannot apply tangent constraint between curve and circle on 2D sketch in Inventor Forum

Cannot apply tangent constraint between curve and circle on 2D sketch

xandmore3 — Sun, 17 Jul 2022 19:04:20 GMT

Hello everyone! Could you help me with that please: for some reason I cannot apply tangent constraint between circle and spline curve. Curve is never being highlighted when I hover it 🤷
What could it be?

I tried to draw a new curve and go through the same steps and it worked - it allowed me to apply a tangent constraint. So that might be that the problem is somehow related to the previous curve.

I'm attaching a part file, so as a recording, showing the problem.

Thank you! 🙇

Re: Cannot apply tangent constraint between curve and circle on 2D sketch

JDMather — Sun, 17 Jul 2022 20:12:51 GMT

If that were my design - I would sketch with the Origin as a datum at a logical location.

I would sketch the rectangle, circles and slot relative to the Origin datum.

For the spline I would sketch only one curve and use Shell to get the Offset.

My sketch would be fully defined.

Re: Cannot apply tangent constraint between curve and circle on 2D sketch

WHolzwarth — Sun, 17 Jul 2022 20:25:06 GMT

I didn't look at fully constraining the sketch, but I've added an offset spline for the center of the circle.

Re: Cannot apply tangent constraint between curve and circle on 2D sketch

xandmore3 — Sun, 17 Jul 2022 21:49:27 GMT

@WHolzwarth @JDMather
Thank you, gentleman! The solution suggested by @WHolzwarth works perfectly fine 👍

Anyways, I'd love to know the reason of that inability to apply tangent constraint to the circle and the spline.

I didn't look at fully constraining the sketch

After I removed all the other constraints on the sketch I still couldn't apply it 🤔

Is there any limitations of applying tangent constraints towards splines? Where could I find more information about it?

For the spline I would sketch only one curve and use Shell to get the Offset.

Is it crucial to have a single curve to be able to apply tangent constraints?

Re: Cannot apply tangent constraint between curve and circle on 2D sketch

SBix26 — Mon, 18 Jul 2022 00:52:25 GMT

I experienced something like this recently, too. I could not get a line to constrain tangent to a spline curve in a 2D sketch. Either one of them would highlight as the first pick, but for the second pick, nothing was available to select. This was in Inventor 2022.3.1.

Sam B

Inventor Pro 2023.1 | Windows 10 Home 21H2

Re: Cannot apply tangent constraint between curve and circle on 2D sketch

johnsonshiue — Mon, 18 Jul 2022 17:17:37 GMT

Hi! I think this is a limitation in Tangent constraint. It seems that a tangent constraint cannot be established between a circle and a fit-point spline except the handle at a fit point.

The second image shows the tangent constraint between a control-vertex spline and a circle. It is indeed supported. To enable the tangent constraint in this case, right-click on the fit-point spline -> Convert to CV Spline.

Many thanks!