Change Radius of Arc or PolyArc Without Changing Endpoints

[Anonymous]

Hello,

I'm trying to create a dynamic block that allows me to change the radius of an arc or poly-arc without changing the endpoints. Basically, the endpoints will not translate in any direction but the radius will grow or shrink causing the arc to bulge or flatten respectively.

First, I show the issue. Then I show what I need to happen. 

[vinodkl · Accepted solution]

Hi,

The outcome is not possible to achieve with parameters. You need to use constraints to get what your looking for. 

See the screencast for better understanding.

[Anonymous]

I marked your answer as the solution. Thank you.

For understanding, why would you use parameter/actions vs constraints?