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Defining a Dynamic Minimum Value for an Input Field

Question​

> I want to ensure that Attribute B is always at least a certain amount greater than Attribute A. K3 does not support a direct dynamic minimum value for this—how can I still enforce this?

Answer​

K3 currently does not allow direct dynamic minimum values for input fields. However, you can implement the desired behavior as a workaround using a hidden calculated attribute: As soon as the user enters an invalid value, the hidden attribute falls below its own minimum value—the configurator marks the field as invalid and prevents submission.

Implementation​

Assume that Feature B must always be at least X greater than Feature A.

  1. Create a hidden numeric feature: Create a new one, ausgeblendetes Zahlenmerkmal, e.g., “Distance Check”
  2. Set the minimum value: Enter 0 as the minimum value
  3. Define the formula: Define the following Berechnungsformel:
MerkmalB - MerkmalA - X

Replace MerkmalA, MerkmalB, and X with your actual attribute names and the desired minimum distance.

How does this work?​

  • As long as B − A ≥ X, the result is ≥ 0 → no error
  • As soon as B − A < X, the result becomes negative → falls below the minimum value of 0 → the configurator displays a validation error and prevents submission
Example

The sash height must be at least 60 mm greater than the window height:

  • Feature A = Fensterhöhe, Feature B = Flügelhöhe, X = 60
  • Formula: Flügelhöhe - Fensterhöhe - 60
  • Minimum value of the hidden feature: 0

Further Information​

  • Input validation
  • Dependent numeric values
  • Calculated characteristic as a constraint