I.D. cannot exceed O.D. but unlimited values are allowed

[KendredCooper]

So, can anyone figure out how to do this in AutoCAD Dynamic Blocks?  See attached drawing.  Say I want to put a control in place to keep diameters from surpassing each other.  Imagine creating a step from an O.D., stepped down to a smaller Dia.  Now imagine putting in a control to keep the Step Dia value from exceeding the O.D. value but sometimes those values can be equal to each other, depending upon the design configuration… that’s basically what we’re talking about here.  I was thinking this isn’t possible and I’ve been testing it for about an hour.  Now I believe my original thought more and more.  I've tried incorporating a Parametric Dimension and giving it a "Minimum" value of 0.0001" but it locks the distance at the drawn value and also does not allow the Dia's to be changed to a point that would override the dimensioned value of the Parametric Dim.  I would appreciate any help or confirmation that it isn't possible, that anyone could provide.

[j.palmeL29YX · Accepted solution]

Check the attachment if it meets your goal. 

[KendredCooper]

That is it perfectly!  Now... how was this accomplished?  I do not even see any Dynamic Actions within the block that is permitting the stretching of the Dia's.

[j.palmeL29YX]

It is completely done using constraints. 

I hope the video is self explaining. 

Of course if you still need further explanation, ask again. 

[KendredCooper]

My apologies for the delay.  Got pulled onto 20 other things.

I've tried the solution you showed but there's got to be something that I'm missing but I cannot tell what it is.  See attached.

[j.palmeL29YX]

First: You should not use Dynamic Parameters (Distance1, Distance2) AND constraints (d1, d2, d3) at the same time in a block definition. Such blocks will fail in most cases.

Suggestion to solve your request:

- Draw the figure and add geometric constraints to get a geometric stable shape.

- Add a Horizontal Constraint Parameter OR (_bcparameter command) to the lower radius. The user can choose any value.

- draw a Dummy Object (here the horizontal line). To drive their dimension (length) add a Horizontal Constraint Parameter IR (_bcparameter command). The user later can choose any value. (In the attached image I moved both a little up for better understanding. The Line I would convert to Construction line (to disable the visibility) and the grip I would move to a better suitable position)

- to drive the inner radius of the shape add a Dynamic Dimension d1 (_dclinear command). Its value is a formula to get always the smaller value of IR and OR. So the upper radius d1 can never be greater than the lower radius OR. 

If you need more help to one of the upper steps let me know, ...

[KendredCooper]

Unfortunately we have to Dynamic Parameters due to coding that is reading those Distance1, Distance2, etc Parameter names as well as Actions that have been built to enable end users to easily modify the block geometry.  Our initial suspicions were that the I.D. to O.D. control was not possible and this basically confirms our thoughts.  I do appreciate all of the effort you put into helping me on this one.  We have to push forward using the Dynamic Parameters workflow simply due to the amount of work that's already been put into the coding and utility building that references those Dynamic Paremeters.

[j.palmeL29YX]

OK, or better not okay: without using constraints I don't know a way to solve your issue. I'm sorry.