How to fix a grip to the midpoint of an arc that changes?

[timgrote]

I’m trying to create a parametric block that looks like a piece of pie. It will be inserted programmatically with initial values and the user will be able to adjust it via 3 grips.  

I’m having a hard time figuring out how to fix the radius grip to the midpoint of the arc, it moves when other parameters are adjusted.

Also is there a way to make all three grips stretch the radius of the circle?

[hwalker]

I don't have full AutoCAD, so cannot fully help.

However, I would put a rotational "dimension" constraint on the radius line and make it half of the swing.

[timgrote]

Thanks for the input @hwalker. I'm not well versed in parameters and constraints, so I'm not clear on what you mean by a rotational "dimension" constraint. I tried adding an Angular Constraint Parameter but it wouldn't accept the radius constraint as the second argument. Is there some other type of constraint I should be using? 

I appreciate the time and attention.

[j.palmeL29YX · Accepted solution]

Try the attached attempt. 

>>Click<<

A small problem: After inserting the block (or after resetting to its initial values) you can not immediately drag the grip for ang2 (which is used for the rotation of the complete block). Either you have at least once to type a value of ang2 via the properties window or you drag one of the other both grips first. 

(Or with other words: Your first "action" with a new inserted or resetted block must not be to drag the right grip)

[hwalker]

@timgrote Jürgen got what I was trying to say. As I said I don't have full AutoCAD so wasn't quite sure what I was talking about

[j.palmeL29YX]

Didn't the suggestion >>above<< help you to solve the issue? Or do you have further questions?