About the Functional Shape Design App

This topic presents the functional concepts associated to the Functional Shape Design app.

A function can be seen as a set of contributions that are defined by specifications and a behavior.

Specifications (i.e. geometric inputs, parameters, etc.) define the geometric shape of the contribution. The behavior defines how the contribution will interact in the system. It is composed of tree main attributes (category, priority and sign) that are explained below.

This page discusses:

What Kind of Features are Used?

The input data for Functional Shape Design are an existing styling surface and a flag that sets either positive or negative sides (Push & Pull).

The goal is to create functions that will push, pull and cut basic shape to fulfil functional specifications.

The default available categories are:

  • Cut
  • Protected zone
  • Contact
  • Stiffener.



Default priorities exist between these features. The higher priority is given to the cut, then the protected zone, the contact and at last the stiffener. This means that, if there is overlapping, a cut trims any other feature, a protected zone trims a contact or a stiffener and a contact trims a stiffener.

Tip: The creation order has no importance.

However, for design purpose, it may be useful that the priority of a feature be always higher than the priority of any other feature, including existing features and features to be created. Therefore you can define features with back and front priorities: a "back" feature will always have a low priority whereas a "front" feature will always have a high priority.

What are Function Modifiers?

A function modifier is a function that modifies an existing function. It alters selected features, more precisely their shapes, by adding or subtracting material from them.

When defining a function modifier, you have to choose the function you want to modify and the type of Boolean operation you want to perform to modify input function shapes:

  • Push: positive trim
  • Pull: negative Trim
  • Inner cut: inner split
  • Outer cut: outer split.

For more information about feature modifiers, see Functional Modeling Part User's Guide.

What are Contextual Functions?

This sub-topic presents the two kinds of functions that exist in the Functional Shape Design app:

  • Functional functions, i.e. functions that use context free inputs, for example, a generic function based on an external reference geometry.
  • Contextual functions, i.e. functions that operate an intermediate state of the structure, for example, a bead that runs on a surface that contains other functions.