Modify a constraint based on a formula applied to value of another constraint

[dthompsonPHSGY]

Hello, 

I am attempting to model a 3 stage telescopic assembly.  The middle stage moves simultaneously with the third stage but at half speed/distance.  Is there a way to modify a constraint based on a formula applied to another constraint.  For example Constraint 1 is applied to the third telescopic stage and is a +/- constraint from 0" to 100" relative to a fixed reference surface.  Constraint 2 would then be applied to the second telescopic stage and would be (present value of constraint 1)/2 relative to the reference surface.  Clicking and dragging the third stage would then result in the second stage moving at half speed/distance.  Ideally I want to do this in the model itself, not an animation, so I can drag around as the design is evolving.  Is there a way to do this, or any other ideas?

Thanks

Dan

[JDMather]

Attach your assembly here.

[mcgyvr]

Sure

When a constraint is created a parameter is created just like a parameter is created when a dimension is created.. (see fx button in Inventor.. Assemble tab.. Manage section)

Another constraint can reference that parameter

Create your first constraint and "d0" is created..

Second constraint can be d0/2 or whatever you want

You can then "drive" the first constraint and the second would follow..

[Anonymous]

you should name the parameter where the value for the constraint offset is stored. To do this when you place your first constraint type "Constraint1Distance = 6" in the Offset typebox. 6 here could be any number or formula actualy. When making the second constraint you can just type ConstraintDistance2 = 2*ConstraintDistance1 which would in this case result in an offset of 12 for the second constraint

[johnsonshiue]

Hi! Dan,

You can write such equation in the assembly parameters table. Or, you can use iLogic to set up relationship between multiple parameters within the assembly or across the components.

Please share the files here so forum experts can take a look. It should be fairly easy to do.

Many thanks!